Sony STR-DE635 recieiver won't power up

Discussion in 'Electronic Repair' started by ampapa, Oct 2, 2004.

  1. ampapa

    ampapa Guest

    First off I'd like to say, "Hello." to the group. I hope I can gain
    some knowledge from the group's collective input.

    I have a Sony STR-DE635 stereo receiver that will not turn on and I
    would like to investigate into maybe seeing if I can repair it. I
    found a set of schematics on this site which I believe will
    definitely help.(http://www.eserviceinfo.com/index.php?what=search2)

    I'm guessing but I think that the problem is related to the power
    supply? On p.13 of this .PDF manual it has an A/C and D/C schematic,
    this receiver has a seperate board for each. I probed the A/C board
    and found that it has voltage out to the "Digital" board of a little
    over 12 volts but when I try to test the pins on CNV902 I thought I
    should be getting appx. 110 A/C but only get appx. 2? CNV902 is a
    simple 2 wire connector leading directly to a transformer.

    My common sense is telling me that why would I need a transformaer
    the size of Kansas for only 2 volts A/C? So, I'm guessing this might
    have something to do with it? I could be in left field due to my lack
    of knowledge and inexperience, that's why I'm hoping you guy's/girl's
    can shed some light.

    Thanks for any suggestions or hints you can provide.
    ampapa, Oct 2, 2004
    #1
    1. Advertising

  2. ampapa

    Jerry G. Guest

    These sets can be very difficult to reliably and safely troubleshoot and
    service. The proper training, service experience, product training, and a
    solid background in electronics theory would be an asset to do service on
    these sets.

    In going by the way you are presenting your questions, I would suggest you
    give the unit out to an authorized service centre to have an estimate done
    for you.

    When servicing these sets, the main procedure is to verify all the voltages
    from the power supply. If there are some missing, then you must start to
    troubleshoot the unit from the point of loss, and go on from there. It is
    possible that there is a short somewhere, and has damaged the power supply,
    or some other components failed, and thus caused other types of damage.

    It is very common in these receivers that the output devices and their
    respective driver devices, become shorted. In this event, the power supply,
    and a number of other support components may be damaged. You will have to
    determine this.

    --

    Jerry G.
    ==========================


    "ampapa" <> wrote in message
    news:...
    First off I'd like to say, "Hello." to the group. I hope I can gain
    some knowledge from the group's collective input.

    I have a Sony STR-DE635 stereo receiver that will not turn on and I
    would like to investigate into maybe seeing if I can repair it. I
    found a set of schematics on this site which I believe will
    definitely help.(http://www.eserviceinfo.com/index.php?what=search2)

    I'm guessing but I think that the problem is related to the power
    supply? On p.13 of this .PDF manual it has an A/C and D/C schematic,
    this receiver has a seperate board for each. I probed the A/C board
    and found that it has voltage out to the "Digital" board of a little
    over 12 volts but when I try to test the pins on CNV902 I thought I
    should be getting appx. 110 A/C but only get appx. 2? CNV902 is a
    simple 2 wire connector leading directly to a transformer.

    My common sense is telling me that why would I need a transformaer
    the size of Kansas for only 2 volts A/C? So, I'm guessing this might
    have something to do with it? I could be in left field due to my lack
    of knowledge and inexperience, that's why I'm hoping you guy's/girl's
    can shed some light.

    Thanks for any suggestions or hints you can provide.
    Jerry G., Oct 2, 2004
    #2
    1. Advertising

  3. These models often have fuses sort of hidden under a circuit board attached
    to the transformer. If these fuses are blown you probably have a blown amp
    channel. Sometimes just the output transistors for a given channel are bad,
    sometimes there are other small parts bad. Occasionally a circuit mod is
    required to lessen the bias at startup.

    Mark Z.


    "ampapa" <> wrote in message
    news:...
    > First off I'd like to say, "Hello." to the group. I hope I can gain
    > some knowledge from the group's collective input.
    >
    > I have a Sony STR-DE635 stereo receiver that will not turn on and I
    > would like to investigate into maybe seeing if I can repair it. I
    > found a set of schematics on this site which I believe will
    > definitely help.(http://www.eserviceinfo.com/index.php?what=search2)
    >
    > I'm guessing but I think that the problem is related to the power
    > supply? On p.13 of this .PDF manual it has an A/C and D/C schematic,
    > this receiver has a seperate board for each. I probed the A/C board
    > and found that it has voltage out to the "Digital" board of a little
    > over 12 volts but when I try to test the pins on CNV902 I thought I
    > should be getting appx. 110 A/C but only get appx. 2? CNV902 is a
    > simple 2 wire connector leading directly to a transformer.
    >
    > My common sense is telling me that why would I need a transformaer
    > the size of Kansas for only 2 volts A/C? So, I'm guessing this might
    > have something to do with it? I could be in left field due to my lack
    > of knowledge and inexperience, that's why I'm hoping you guy's/girl's
    > can shed some light.
    >
    > Thanks for any suggestions or hints you can provide.
    Mark D. Zacharias, Oct 2, 2004
    #3
  4. ampapa

    ampapa Guest

    Jerry,

    Thanks for the response.

    I realize that I am not qualified or have any experience in
    electronics repair which is why I would deem this as a
    hobby/experiement and not a profession.

    Would it be outside the scope of this forum to ask if my logic in the
    orignal post was corect? Does in fact the transformer expect to see
    110v coming in from the A/C board?

    >"I probed the A/C board and found that it has voltage out to the

    "Digital" >board of a little over 12 volts but when I try to test the
    pins on CNV902 I >thought I should be getting appx. 110 A/C but only
    get appx. 2? CNV902 is a
    >simple 2 wire connector leading directly to a transformer."



    This in fact is what I am trying to establish.

    > When servicing these sets, the main procedure is to verify all the voltages
    > from the power supply.



    Thanks for any additional help you can give.

    AJM,



    "Jerry G." <> wrote in message news:<>...
    > These sets can be very difficult to reliably and safely troubleshoot and
    > service. The proper training, service experience, product training, and a
    > solid background in electronics theory would be an asset to do service on
    > these sets.
    >
    > In going by the way you are presenting your questions, I would suggest you
    > give the unit out to an authorized service centre to have an estimate done
    > for you.
    >
    > When servicing these sets, the main procedure is to verify all the voltages
    > from the power supply. If there are some missing, then you must start to
    > troubleshoot the unit from the point of loss, and go on from there. It is
    > possible that there is a short somewhere, and has damaged the power supply,
    > or some other components failed, and thus caused other types of damage.
    >
    > It is very common in these receivers that the output devices and their
    > respective driver devices, become shorted. In this event, the power supply,
    > and a number of other support components may be damaged. You will have to
    > determine this.
    >
    > --
    >
    > Jerry G.
    > ==========================
    >
    >
    > "ampapa" <> wrote in message
    > news:...
    > First off I'd like to say, "Hello." to the group. I hope I can gain
    > some knowledge from the group's collective input.
    >
    > I have a Sony STR-DE635 stereo receiver that will not turn on and I
    > would like to investigate into maybe seeing if I can repair it. I
    > found a set of schematics on this site which I believe will
    > definitely help.(http://www.eserviceinfo.com/index.php?what=search2)
    >
    > I'm guessing but I think that the problem is related to the power
    > supply? On p.13 of this .PDF manual it has an A/C and D/C schematic,
    > this receiver has a seperate board for each. I probed the A/C board
    > and found that it has voltage out to the "Digital" board of a little
    > over 12 volts but when I try to test the pins on CNV902 I thought I
    > should be getting appx. 110 A/C but only get appx. 2? CNV902 is a
    > simple 2 wire connector leading directly to a transformer.
    >
    > My common sense is telling me that why would I need a transformaer
    > the size of Kansas for only 2 volts A/C? So, I'm guessing this might
    > have something to do with it? I could be in left field due to my lack
    > of knowledge and inexperience, that's why I'm hoping you guy's/girl's
    > can shed some light.
    >
    > Thanks for any suggestions or hints you can provide.
    ampapa, Oct 2, 2004
    #4
  5. ampapa

    ampapa Guest

    Are you saying there would be a fuse physical under the board or just
    hidden by another board? This thing has 6 fuses and all checked out
    fine.

    If the A/C board isn't putting out the correct voltage to the
    transformer then certainly it's going to have problems. That's why I
    was hoping someone would be able to tell by the schematics if in fact
    the A/C board should be putting out 110, if not then what voltage
    should I be looking for on CNV902?

    Thanks.




    "Mark D. Zacharias" <> wrote in message news:<>...
    > These models often have fuses sort of hidden under a circuit board attached
    > to the transformer. If these fuses are blown you probably have a blown amp
    > channel. Sometimes just the output transistors for a given channel are bad,
    > sometimes there are other small parts bad. Occasionally a circuit mod is
    > required to lessen the bias at startup.
    >
    > Mark Z.
    >
    >
    > "ampapa" <> wrote in message
    > news:...
    > > First off I'd like to say, "Hello." to the group. I hope I can gain
    > > some knowledge from the group's collective input.
    > >
    > > I have a Sony STR-DE635 stereo receiver that will not turn on and I
    > > would like to investigate into maybe seeing if I can repair it. I
    > > found a set of schematics on this site which I believe will
    > > definitely help.(http://www.eserviceinfo.com/index.php?what=search2)
    > >
    > > I'm guessing but I think that the problem is related to the power
    > > supply? On p.13 of this .PDF manual it has an A/C and D/C schematic,
    > > this receiver has a seperate board for each. I probed the A/C board
    > > and found that it has voltage out to the "Digital" board of a little
    > > over 12 volts but when I try to test the pins on CNV902 I thought I
    > > should be getting appx. 110 A/C but only get appx. 2? CNV902 is a
    > > simple 2 wire connector leading directly to a transformer.
    > >
    > > My common sense is telling me that why would I need a transformaer
    > > the size of Kansas for only 2 volts A/C? So, I'm guessing this might
    > > have something to do with it? I could be in left field due to my lack
    > > of knowledge and inexperience, that's why I'm hoping you guy's/girl's
    > > can shed some light.
    > >
    > > Thanks for any suggestions or hints you can provide.
    ampapa, Oct 2, 2004
    #5
  6. ampapa

    ampapa Guest

    Sorry if this is a double post.

    Mark, are you saying there might be a fuse literaly underneath a
    circuit board and not necessarily hidden from view by a circuit board?
    I checked about 5 or 6 fuses in this thing and all checked fine.

    My biggest problem is that when I read the schematic I can't tell if
    the transformer is supposed to be getting 110v from the A/C board on
    CNV902? If it is then I can trace it from there. That's my real
    dilema.

    The schematic can be found here
    (http://www.eserviceinfo.com/index.php?what=search2).

    Thanks,


    "Mark D. Zacharias" <> wrote in message news:<>...
    > These models often have fuses sort of hidden under a circuit board attached
    > to the transformer. If these fuses are blown you probably have a blown amp
    > channel. Sometimes just the output transistors for a given channel are bad,
    > sometimes there are other small parts bad. Occasionally a circuit mod is
    > required to lessen the bias at startup.
    >
    > Mark Z.
    >
    >
    > "ampapa" <> wrote in message
    > news:...
    > > First off I'd like to say, "Hello." to the group. I hope I can gain
    > > some knowledge from the group's collective input.
    > >
    > > I have a Sony STR-DE635 stereo receiver that will not turn on and I
    > > would like to investigate into maybe seeing if I can repair it. I
    > > found a set of schematics on this site which I believe will
    > > definitely help.(http://www.eserviceinfo.com/index.php?what=search2)
    > >
    > > I'm guessing but I think that the problem is related to the power
    > > supply? On p.13 of this .PDF manual it has an A/C and D/C schematic,
    > > this receiver has a seperate board for each. I probed the A/C board
    > > and found that it has voltage out to the "Digital" board of a little
    > > over 12 volts but when I try to test the pins on CNV902 I thought I
    > > should be getting appx. 110 A/C but only get appx. 2? CNV902 is a
    > > simple 2 wire connector leading directly to a transformer.
    > >
    > > My common sense is telling me that why would I need a transformaer
    > > the size of Kansas for only 2 volts A/C? So, I'm guessing this might
    > > have something to do with it? I could be in left field due to my lack
    > > of knowledge and inexperience, that's why I'm hoping you guy's/girl's
    > > can shed some light.
    > >
    > > Thanks for any suggestions or hints you can provide.
    ampapa, Oct 2, 2004
    #6
  7. If all the fuses are OK, then the power transformer probably isn't getting
    voltage from the turn-on relay. Does it click when you press the Power
    button? CNV902 gets no AC voltage to speak of til this relay fires. (I
    assume your voltmeter is set to measure AC voltage)

    Mark Z.


    "ampapa" <> wrote in message
    news:...
    > Sorry if this is a double post.
    >
    > Mark, are you saying there might be a fuse literaly underneath a
    > circuit board and not necessarily hidden from view by a circuit board?
    > I checked about 5 or 6 fuses in this thing and all checked fine.
    >
    > My biggest problem is that when I read the schematic I can't tell if
    > the transformer is supposed to be getting 110v from the A/C board on
    > CNV902? If it is then I can trace it from there. That's my real
    > dilema.
    >
    > The schematic can be found here
    > (http://www.eserviceinfo.com/index.php?what=search2).
    >
    > Thanks,
    >
    >
    > "Mark D. Zacharias" <> wrote in message
    > news:<>...
    >> These models often have fuses sort of hidden under a circuit board
    >> attached
    >> to the transformer. If these fuses are blown you probably have a blown
    >> amp
    >> channel. Sometimes just the output transistors for a given channel are
    >> bad,
    >> sometimes there are other small parts bad. Occasionally a circuit mod is
    >> required to lessen the bias at startup.
    >>
    >> Mark Z.
    >>
    >>
    >> "ampapa" <> wrote in message
    >> news:...
    >> > First off I'd like to say, "Hello." to the group. I hope I can gain
    >> > some knowledge from the group's collective input.
    >> >
    >> > I have a Sony STR-DE635 stereo receiver that will not turn on and I
    >> > would like to investigate into maybe seeing if I can repair it. I
    >> > found a set of schematics on this site which I believe will
    >> > definitely help.(http://www.eserviceinfo.com/index.php?what=search2)
    >> >
    >> > I'm guessing but I think that the problem is related to the power
    >> > supply? On p.13 of this .PDF manual it has an A/C and D/C schematic,
    >> > this receiver has a seperate board for each. I probed the A/C board
    >> > and found that it has voltage out to the "Digital" board of a little
    >> > over 12 volts but when I try to test the pins on CNV902 I thought I
    >> > should be getting appx. 110 A/C but only get appx. 2? CNV902 is a
    >> > simple 2 wire connector leading directly to a transformer.
    >> >
    >> > My common sense is telling me that why would I need a transformaer
    >> > the size of Kansas for only 2 volts A/C? So, I'm guessing this might
    >> > have something to do with it? I could be in left field due to my lack
    >> > of knowledge and inexperience, that's why I'm hoping you guy's/girl's
    >> > can shed some light.
    >> >
    >> > Thanks for any suggestions or hints you can provide.
    Mark D. Zacharias, Oct 2, 2004
    #7
  8. ampapa

    ampapa Guest

    No click when I push the power button and I do have my voltmeter set
    to A/C.

    By looking at the schematic am I correct that the transformer should
    be seeing appx. 110v? or should I be looking for some other voltage
    being delivered to the transformer?

    Also, in order for the A/C board to "enable" the turn-on relay by the
    on/off switch then I should be seeing voltage coming back from the
    "Digital" board correct? I see the header that leads to the "Digital"
    board has 4 legs, GND, 12V, P_OFF and P.RY. Are these designations
    specific to the industry as to what they represent?


    Thanks for the help,



    "Mark D. Zacharias" <> wrote in message news:<>...
    > If all the fuses are OK, then the power transformer probably isn't getting
    > voltage from the turn-on relay. Does it click when you press the Power
    > button? CNV902 gets no AC voltage to speak of til this relay fires. (I
    > assume your voltmeter is set to measure AC voltage)
    >
    > Mark Z.
    >
    >
    > "ampapa" <> wrote in message
    > news:...
    > > Sorry if this is a double post.
    > >
    > > Mark, are you saying there might be a fuse literaly underneath a
    > > circuit board and not necessarily hidden from view by a circuit board?
    > > I checked about 5 or 6 fuses in this thing and all checked fine.
    > >
    > > My biggest problem is that when I read the schematic I can't tell if
    > > the transformer is supposed to be getting 110v from the A/C board on
    > > CNV902? If it is then I can trace it from there. That's my real
    > > dilema.
    > >
    > > The schematic can be found here
    > > (http://www.eserviceinfo.com/index.php?what=search2).
    > >
    > > Thanks,
    > >
    > >
    > > "Mark D. Zacharias" <> wrote in message
    > > news:<>...
    > >> These models often have fuses sort of hidden under a circuit board
    > >> attached
    > >> to the transformer. If these fuses are blown you probably have a blown
    > >> amp
    > >> channel. Sometimes just the output transistors for a given channel are
    > >> bad,
    > >> sometimes there are other small parts bad. Occasionally a circuit mod is
    > >> required to lessen the bias at startup.
    > >>
    > >> Mark Z.
    > >>
    > >>
    > >> "ampapa" <> wrote in message
    > >> news:...
    > >> > First off I'd like to say, "Hello." to the group. I hope I can gain
    > >> > some knowledge from the group's collective input.
    > >> >
    > >> > I have a Sony STR-DE635 stereo receiver that will not turn on and I
    > >> > would like to investigate into maybe seeing if I can repair it. I
    > >> > found a set of schematics on this site which I believe will
    > >> > definitely help.(http://www.eserviceinfo.com/index.php?what=search2)
    > >> >
    > >> > I'm guessing but I think that the problem is related to the power
    > >> > supply? On p.13 of this .PDF manual it has an A/C and D/C schematic,
    > >> > this receiver has a seperate board for each. I probed the A/C board
    > >> > and found that it has voltage out to the "Digital" board of a little
    > >> > over 12 volts but when I try to test the pins on CNV902 I thought I
    > >> > should be getting appx. 110 A/C but only get appx. 2? CNV902 is a
    > >> > simple 2 wire connector leading directly to a transformer.
    > >> >
    > >> > My common sense is telling me that why would I need a transformaer
    > >> > the size of Kansas for only 2 volts A/C? So, I'm guessing this might
    > >> > have something to do with it? I could be in left field due to my lack
    > >> > of knowledge and inexperience, that's why I'm hoping you guy's/girl's
    > >> > can shed some light.
    > >> >
    > >> > Thanks for any suggestions or hints you can provide.
    ampapa, Oct 3, 2004
    #8
  9. Measure from point 12V with respect to ground. I suspect your standby
    transformer is bad.

    Mark Z.


    "ampapa" <> wrote in message
    news:...
    > No click when I push the power button and I do have my voltmeter set
    > to A/C.
    >
    > By looking at the schematic am I correct that the transformer should
    > be seeing appx. 110v? or should I be looking for some other voltage
    > being delivered to the transformer?
    >
    > Also, in order for the A/C board to "enable" the turn-on relay by the
    > on/off switch then I should be seeing voltage coming back from the
    > "Digital" board correct? I see the header that leads to the "Digital"
    > board has 4 legs, GND, 12V, P_OFF and P.RY. Are these designations
    > specific to the industry as to what they represent?
    >
    >
    > Thanks for the help,
    >
    >
    >
    > "Mark D. Zacharias" <> wrote in message
    > news:<>...
    >> If all the fuses are OK, then the power transformer probably isn't
    >> getting
    >> voltage from the turn-on relay. Does it click when you press the Power
    >> button? CNV902 gets no AC voltage to speak of til this relay fires. (I
    >> assume your voltmeter is set to measure AC voltage)
    >>
    >> Mark Z.
    >>
    >>
    >> "ampapa" <> wrote in message
    >> news:...
    >> > Sorry if this is a double post.
    >> >
    >> > Mark, are you saying there might be a fuse literaly underneath a
    >> > circuit board and not necessarily hidden from view by a circuit board?
    >> > I checked about 5 or 6 fuses in this thing and all checked fine.
    >> >
    >> > My biggest problem is that when I read the schematic I can't tell if
    >> > the transformer is supposed to be getting 110v from the A/C board on
    >> > CNV902? If it is then I can trace it from there. That's my real
    >> > dilema.
    >> >
    >> > The schematic can be found here
    >> > (http://www.eserviceinfo.com/index.php?what=search2).
    >> >
    >> > Thanks,
    >> >
    >> >
    >> > "Mark D. Zacharias" <> wrote in message
    >> > news:<>...
    >> >> These models often have fuses sort of hidden under a circuit board
    >> >> attached
    >> >> to the transformer. If these fuses are blown you probably have a blown
    >> >> amp
    >> >> channel. Sometimes just the output transistors for a given channel are
    >> >> bad,
    >> >> sometimes there are other small parts bad. Occasionally a circuit mod
    >> >> is
    >> >> required to lessen the bias at startup.
    >> >>
    >> >> Mark Z.
    >> >>
    >> >>
    >> >> "ampapa" <> wrote in message
    >> >> news:...
    >> >> > First off I'd like to say, "Hello." to the group. I hope I can gain
    >> >> > some knowledge from the group's collective input.
    >> >> >
    >> >> > I have a Sony STR-DE635 stereo receiver that will not turn on and I
    >> >> > would like to investigate into maybe seeing if I can repair it. I
    >> >> > found a set of schematics on this site which I believe will
    >> >> > definitely help.(http://www.eserviceinfo.com/index.php?what=search2)
    >> >> >
    >> >> > I'm guessing but I think that the problem is related to the power
    >> >> > supply? On p.13 of this .PDF manual it has an A/C and D/C schematic,
    >> >> > this receiver has a seperate board for each. I probed the A/C board
    >> >> > and found that it has voltage out to the "Digital" board of a little
    >> >> > over 12 volts but when I try to test the pins on CNV902 I thought I
    >> >> > should be getting appx. 110 A/C but only get appx. 2? CNV902 is a
    >> >> > simple 2 wire connector leading directly to a transformer.
    >> >> >
    >> >> > My common sense is telling me that why would I need a transformaer
    >> >> > the size of Kansas for only 2 volts A/C? So, I'm guessing this might
    >> >> > have something to do with it? I could be in left field due to my
    >> >> > lack
    >> >> > of knowledge and inexperience, that's why I'm hoping you
    >> >> > guy's/girl's
    >> >> > can shed some light.
    >> >> >
    >> >> > Thanks for any suggestions or hints you can provide.
    Mark D. Zacharias, Oct 3, 2004
    #9
  10. ampapa

    ampapa Guest

    The "standby transformer" is that T902 on the schematic?

    I've got 13.5V on the header that leads to the "Digital" board.



    "Mark D. Zacharias" <> wrote in message news:<>...
    > Measure from point 12V with respect to ground. I suspect your standby
    > transformer is bad.
    >
    > Mark Z.
    >
    >
    > "ampapa" <> wrote in message
    > news:...
    > > No click when I push the power button and I do have my voltmeter set
    > > to A/C.
    > >
    > > By looking at the schematic am I correct that the transformer should
    > > be seeing appx. 110v? or should I be looking for some other voltage
    > > being delivered to the transformer?
    > >
    > > Also, in order for the A/C board to "enable" the turn-on relay by the
    > > on/off switch then I should be seeing voltage coming back from the
    > > "Digital" board correct? I see the header that leads to the "Digital"
    > > board has 4 legs, GND, 12V, P_OFF and P.RY. Are these designations
    > > specific to the industry as to what they represent?
    > >
    > >
    > > Thanks for the help,
    > >
    > >
    > >
    > > "Mark D. Zacharias" <> wrote in message
    > > news:<>...
    > >> If all the fuses are OK, then the power transformer probably isn't
    > >> getting
    > >> voltage from the turn-on relay. Does it click when you press the Power
    > >> button? CNV902 gets no AC voltage to speak of til this relay fires. (I
    > >> assume your voltmeter is set to measure AC voltage)
    > >>
    > >> Mark Z.
    > >>
    > >>
    > >> "ampapa" <> wrote in message
    > >> news:...
    > >> > Sorry if this is a double post.
    > >> >
    > >> > Mark, are you saying there might be a fuse literaly underneath a
    > >> > circuit board and not necessarily hidden from view by a circuit board?
    > >> > I checked about 5 or 6 fuses in this thing and all checked fine.
    > >> >
    > >> > My biggest problem is that when I read the schematic I can't tell if
    > >> > the transformer is supposed to be getting 110v from the A/C board on
    > >> > CNV902? If it is then I can trace it from there. That's my real
    > >> > dilema.
    > >> >
    > >> > The schematic can be found here
    > >> > (http://www.eserviceinfo.com/index.php?what=search2).
    > >> >
    > >> > Thanks,
    > >> >
    > >> >
    > >> > "Mark D. Zacharias" <> wrote in message
    > >> > news:<>...
    > >> >> These models often have fuses sort of hidden under a circuit board
    > >> >> attached
    > >> >> to the transformer. If these fuses are blown you probably have a blown
    > >> >> amp
    > >> >> channel. Sometimes just the output transistors for a given channel are
    > >> >> bad,
    > >> >> sometimes there are other small parts bad. Occasionally a circuit mod
    > >> >> is
    > >> >> required to lessen the bias at startup.
    > >> >>
    > >> >> Mark Z.
    > >> >>
    > >> >>
    > >> >> "ampapa" <> wrote in message
    > >> >> news:...
    > >> >> > First off I'd like to say, "Hello." to the group. I hope I can gain
    > >> >> > some knowledge from the group's collective input.
    > >> >> >
    > >> >> > I have a Sony STR-DE635 stereo receiver that will not turn on and I
    > >> >> > would like to investigate into maybe seeing if I can repair it. I
    > >> >> > found a set of schematics on this site which I believe will
    > >> >> > definitely help.(http://www.eserviceinfo.com/index.php?what=search2)
    > >> >> >
    > >> >> > I'm guessing but I think that the problem is related to the power
    > >> >> > supply? On p.13 of this .PDF manual it has an A/C and D/C schematic,
    > >> >> > this receiver has a seperate board for each. I probed the A/C board
    > >> >> > and found that it has voltage out to the "Digital" board of a little
    > >> >> > over 12 volts but when I try to test the pins on CNV902 I thought I
    > >> >> > should be getting appx. 110 A/C but only get appx. 2? CNV902 is a
    > >> >> > simple 2 wire connector leading directly to a transformer.
    > >> >> >
    > >> >> > My common sense is telling me that why would I need a transformaer
    > >> >> > the size of Kansas for only 2 volts A/C? So, I'm guessing this might
    > >> >> > have something to do with it? I could be in left field due to my
    > >> >> > lack
    > >> >> > of knowledge and inexperience, that's why I'm hoping you
    > >> >> > guy's/girl's
    > >> >> > can shed some light.
    > >> >> >
    > >> >> > Thanks for any suggestions or hints you can provide.
    ampapa, Oct 4, 2004
    #10
  11. Well, you need to check the standby voltages on the digital board. Q1205
    appears to be a 5 volt source.

    Mark Z.


    "ampapa" <> wrote in message
    news:...
    > The "standby transformer" is that T902 on the schematic?
    >
    > I've got 13.5V on the header that leads to the "Digital" board.
    >
    >
    >
    > "Mark D. Zacharias" <> wrote in message
    > news:<>...
    >> Measure from point 12V with respect to ground. I suspect your standby
    >> transformer is bad.
    >>
    >> Mark Z.
    >>
    >>
    >> "ampapa" <> wrote in message
    >> news:...
    >> > No click when I push the power button and I do have my voltmeter set
    >> > to A/C.
    >> >
    >> > By looking at the schematic am I correct that the transformer should
    >> > be seeing appx. 110v? or should I be looking for some other voltage
    >> > being delivered to the transformer?
    >> >
    >> > Also, in order for the A/C board to "enable" the turn-on relay by the
    >> > on/off switch then I should be seeing voltage coming back from the
    >> > "Digital" board correct? I see the header that leads to the "Digital"
    >> > board has 4 legs, GND, 12V, P_OFF and P.RY. Are these designations
    >> > specific to the industry as to what they represent?
    >> >
    >> >
    >> > Thanks for the help,
    >> >
    >> >
    >> >
    >> > "Mark D. Zacharias" <> wrote in message
    >> > news:<>...
    >> >> If all the fuses are OK, then the power transformer probably isn't
    >> >> getting
    >> >> voltage from the turn-on relay. Does it click when you press the Power
    >> >> button? CNV902 gets no AC voltage to speak of til this relay fires. (I
    >> >> assume your voltmeter is set to measure AC voltage)
    >> >>
    >> >> Mark Z.
    >> >>
    >> >>
    >> >> "ampapa" <> wrote in message
    >> >> news:...
    >> >> > Sorry if this is a double post.
    >> >> >
    >> >> > Mark, are you saying there might be a fuse literaly underneath a
    >> >> > circuit board and not necessarily hidden from view by a circuit
    >> >> > board?
    >> >> > I checked about 5 or 6 fuses in this thing and all checked fine.
    >> >> >
    >> >> > My biggest problem is that when I read the schematic I can't tell if
    >> >> > the transformer is supposed to be getting 110v from the A/C board on
    >> >> > CNV902? If it is then I can trace it from there. That's my real
    >> >> > dilema.
    >> >> >
    >> >> > The schematic can be found here
    >> >> > (http://www.eserviceinfo.com/index.php?what=search2).
    >> >> >
    >> >> > Thanks,
    >> >> >
    >> >> >
    >> >> > "Mark D. Zacharias" <> wrote in message
    >> >> > news:<>...
    >> >> >> These models often have fuses sort of hidden under a circuit board
    >> >> >> attached
    >> >> >> to the transformer. If these fuses are blown you probably have a
    >> >> >> blown
    >> >> >> amp
    >> >> >> channel. Sometimes just the output transistors for a given channel
    >> >> >> are
    >> >> >> bad,
    >> >> >> sometimes there are other small parts bad. Occasionally a circuit
    >> >> >> mod
    >> >> >> is
    >> >> >> required to lessen the bias at startup.
    >> >> >>
    >> >> >> Mark Z.
    >> >> >>
    >> >> >>
    >> >> >> "ampapa" <> wrote in message
    >> >> >> news:...
    >> >> >> > First off I'd like to say, "Hello." to the group. I hope I can
    >> >> >> > gain
    >> >> >> > some knowledge from the group's collective input.
    >> >> >> >
    >> >> >> > I have a Sony STR-DE635 stereo receiver that will not turn on and
    >> >> >> > I
    >> >> >> > would like to investigate into maybe seeing if I can repair it. I
    >> >> >> > found a set of schematics on this site which I believe will
    >> >> >> > definitely
    >> >> >> > help.(http://www.eserviceinfo.com/index.php?what=search2)
    >> >> >> >
    >> >> >> > I'm guessing but I think that the problem is related to the power
    >> >> >> > supply? On p.13 of this .PDF manual it has an A/C and D/C
    >> >> >> > schematic,
    >> >> >> > this receiver has a seperate board for each. I probed the A/C
    >> >> >> > board
    >> >> >> > and found that it has voltage out to the "Digital" board of a
    >> >> >> > little
    >> >> >> > over 12 volts but when I try to test the pins on CNV902 I thought
    >> >> >> > I
    >> >> >> > should be getting appx. 110 A/C but only get appx. 2? CNV902 is a
    >> >> >> > simple 2 wire connector leading directly to a transformer.
    >> >> >> >
    >> >> >> > My common sense is telling me that why would I need a
    >> >> >> > transformaer
    >> >> >> > the size of Kansas for only 2 volts A/C? So, I'm guessing this
    >> >> >> > might
    >> >> >> > have something to do with it? I could be in left field due to my
    >> >> >> > lack
    >> >> >> > of knowledge and inexperience, that's why I'm hoping you
    >> >> >> > guy's/girl's
    >> >> >> > can shed some light.
    >> >> >> >
    >> >> >> > Thanks for any suggestions or hints you can provide.
    Mark D. Zacharias, Oct 4, 2004
    #11
  12. ampapa

    ampapa Guest

    I've got 3 readings at the transistor Q1205, the center leg 13.53 and
    the 2 other legs 6.79 and 6.21 respectively. I think this is wrong,
    the schematic shows the "base" at 6.5v?



    "Mark D. Zacharias" <> wrote in message news:<>...
    > Well, you need to check the standby voltages on the digital board. Q1205
    > appears to be a 5 volt source.
    >
    > Mark Z.
    >
    >
    > "ampapa" <> wrote in message
    > news:...
    > > The "standby transformer" is that T902 on the schematic?
    > >
    > > I've got 13.5V on the header that leads to the "Digital" board.
    > >
    > >
    > >
    > > "Mark D. Zacharias" <> wrote in message
    > > news:<>...
    > >> Measure from point 12V with respect to ground. I suspect your standby
    > >> transformer is bad.
    > >>
    > >> Mark Z.
    > >>
    > >>
    > >> "ampapa" <> wrote in message
    > >> news:...
    > >> > No click when I push the power button and I do have my voltmeter set
    > >> > to A/C.
    > >> >
    > >> > By looking at the schematic am I correct that the transformer should
    > >> > be seeing appx. 110v? or should I be looking for some other voltage
    > >> > being delivered to the transformer?
    > >> >
    > >> > Also, in order for the A/C board to "enable" the turn-on relay by the
    > >> > on/off switch then I should be seeing voltage coming back from the
    > >> > "Digital" board correct? I see the header that leads to the "Digital"
    > >> > board has 4 legs, GND, 12V, P_OFF and P.RY. Are these designations
    > >> > specific to the industry as to what they represent?
    > >> >
    > >> >
    > >> > Thanks for the help,
    > >> >
    > >> >
    > >> >
    > >> > "Mark D. Zacharias" <> wrote in message
    > >> > news:<>...
    > >> >> If all the fuses are OK, then the power transformer probably isn't
    > >> >> getting
    > >> >> voltage from the turn-on relay. Does it click when you press the Power
    > >> >> button? CNV902 gets no AC voltage to speak of til this relay fires. (I
    > >> >> assume your voltmeter is set to measure AC voltage)
    > >> >>
    > >> >> Mark Z.
    > >> >>
    > >> >>
    > >> >> "ampapa" <> wrote in message
    > >> >> news:...
    > >> >> > Sorry if this is a double post.
    > >> >> >
    > >> >> > Mark, are you saying there might be a fuse literaly underneath a
    > >> >> > circuit board and not necessarily hidden from view by a circuit
    > >> >> > board?
    > >> >> > I checked about 5 or 6 fuses in this thing and all checked fine.
    > >> >> >
    > >> >> > My biggest problem is that when I read the schematic I can't tell if
    > >> >> > the transformer is supposed to be getting 110v from the A/C board on
    > >> >> > CNV902? If it is then I can trace it from there. That's my real
    > >> >> > dilema.
    > >> >> >
    > >> >> > The schematic can be found here
    > >> >> > (http://www.eserviceinfo.com/index.php?what=search2).
    > >> >> >
    > >> >> > Thanks,
    > >> >> >
    > >> >> >
    > >> >> > "Mark D. Zacharias" <> wrote in message
    > >> >> > news:<>...
    > >> >> >> These models often have fuses sort of hidden under a circuit board
    > >> >> >> attached
    > >> >> >> to the transformer. If these fuses are blown you probably have a
    > >> >> >> blown
    > >> >> >> amp
    > >> >> >> channel. Sometimes just the output transistors for a given channel
    > >> >> >> are
    > >> >> >> bad,
    > >> >> >> sometimes there are other small parts bad. Occasionally a circuit
    > >> >> >> mod
    > >> >> >> is
    > >> >> >> required to lessen the bias at startup.
    > >> >> >>
    > >> >> >> Mark Z.
    > >> >> >>
    > >> >> >>
    > >> >> >> "ampapa" <> wrote in message
    > >> >> >> news:...
    > >> >> >> > First off I'd like to say, "Hello." to the group. I hope I can
    > >> >> >> > gain
    > >> >> >> > some knowledge from the group's collective input.
    > >> >> >> >
    > >> >> >> > I have a Sony STR-DE635 stereo receiver that will not turn on and
    > >> >> >> > I
    > >> >> >> > would like to investigate into maybe seeing if I can repair it. I
    > >> >> >> > found a set of schematics on this site which I believe will
    > >> >> >> > definitely
    > >> >> >> > help.(http://www.eserviceinfo.com/index.php?what=search2)
    > >> >> >> >
    > >> >> >> > I'm guessing but I think that the problem is related to the power
    > >> >> >> > supply? On p.13 of this .PDF manual it has an A/C and D/C
    > >> >> >> > schematic,
    > >> >> >> > this receiver has a seperate board for each. I probed the A/C
    > >> >> >> > board
    > >> >> >> > and found that it has voltage out to the "Digital" board of a
    > >> >> >> > little
    > >> >> >> > over 12 volts but when I try to test the pins on CNV902 I thought
    > >> >> >> > I
    > >> >> >> > should be getting appx. 110 A/C but only get appx. 2? CNV902 is a
    > >> >> >> > simple 2 wire connector leading directly to a transformer.
    > >> >> >> >
    > >> >> >> > My common sense is telling me that why would I need a
    > >> >> >> > transformaer
    > >> >> >> > the size of Kansas for only 2 volts A/C? So, I'm guessing this
    > >> >> >> > might
    > >> >> >> > have something to do with it? I could be in left field due to my
    > >> >> >> > lack
    > >> >> >> > of knowledge and inexperience, that's why I'm hoping you
    > >> >> >> > guy's/girl's
    > >> >> >> > can shed some light.
    > >> >> >> >
    > >> >> >> > Thanks for any suggestions or hints you can provide.
    ampapa, Oct 4, 2004
    #12
  13. ampapa

    ampapa Guest

    I've got 3 readings at the transistor Q1205, the center leg 13.53 and
    the 2 other legs 6.79 and 6.21 respectively. I think this is wrong,
    the schematic shows the "base" at 6.5v?


    "Mark D. Zacharias" <> wrote in message news:<>...
    > Well, you need to check the standby voltages on the digital board. Q1205
    > appears to be a 5 volt source.
    >
    > Mark Z.
    >
    >
    > "ampapa" <> wrote in message
    > news:...
    > > The "standby transformer" is that T902 on the schematic?
    > >
    > > I've got 13.5V on the header that leads to the "Digital" board.
    > >
    > >
    > >
    > > "Mark D. Zacharias" <> wrote in message
    > > news:<>...
    > >> Measure from point 12V with respect to ground. I suspect your standby
    > >> transformer is bad.
    > >>
    > >> Mark Z.
    > >>
    > >>
    > >> "ampapa" <> wrote in message
    > >> news:...
    > >> > No click when I push the power button and I do have my voltmeter set
    > >> > to A/C.
    > >> >
    > >> > By looking at the schematic am I correct that the transformer should
    > >> > be seeing appx. 110v? or should I be looking for some other voltage
    > >> > being delivered to the transformer?
    > >> >
    > >> > Also, in order for the A/C board to "enable" the turn-on relay by the
    > >> > on/off switch then I should be seeing voltage coming back from the
    > >> > "Digital" board correct? I see the header that leads to the "Digital"
    > >> > board has 4 legs, GND, 12V, P_OFF and P.RY. Are these designations
    > >> > specific to the industry as to what they represent?
    > >> >
    > >> >
    > >> > Thanks for the help,
    > >> >
    > >> >
    > >> >
    > >> > "Mark D. Zacharias" <> wrote in message
    > >> > news:<>...
    > >> >> If all the fuses are OK, then the power transformer probably isn't
    > >> >> getting
    > >> >> voltage from the turn-on relay. Does it click when you press the Power
    > >> >> button? CNV902 gets no AC voltage to speak of til this relay fires. (I
    > >> >> assume your voltmeter is set to measure AC voltage)
    > >> >>
    > >> >> Mark Z.
    > >> >>
    > >> >>
    > >> >> "ampapa" <> wrote in message
    > >> >> news:...
    > >> >> > Sorry if this is a double post.
    > >> >> >
    > >> >> > Mark, are you saying there might be a fuse literaly underneath a
    > >> >> > circuit board and not necessarily hidden from view by a circuit
    > >> >> > board?
    > >> >> > I checked about 5 or 6 fuses in this thing and all checked fine.
    > >> >> >
    > >> >> > My biggest problem is that when I read the schematic I can't tell if
    > >> >> > the transformer is supposed to be getting 110v from the A/C board on
    > >> >> > CNV902? If it is then I can trace it from there. That's my real
    > >> >> > dilema.
    > >> >> >
    > >> >> > The schematic can be found here
    > >> >> > (http://www.eserviceinfo.com/index.php?what=search2).
    > >> >> >
    > >> >> > Thanks,
    > >> >> >
    > >> >> >
    > >> >> > "Mark D. Zacharias" <> wrote in message
    > >> >> > news:<>...
    > >> >> >> These models often have fuses sort of hidden under a circuit board
    > >> >> >> attached
    > >> >> >> to the transformer. If these fuses are blown you probably have a
    > >> >> >> blown
    > >> >> >> amp
    > >> >> >> channel. Sometimes just the output transistors for a given channel
    > >> >> >> are
    > >> >> >> bad,
    > >> >> >> sometimes there are other small parts bad. Occasionally a circuit
    > >> >> >> mod
    > >> >> >> is
    > >> >> >> required to lessen the bias at startup.
    > >> >> >>
    > >> >> >> Mark Z.
    > >> >> >>
    > >> >> >>
    > >> >> >> "ampapa" <> wrote in message
    > >> >> >> news:...
    > >> >> >> > First off I'd like to say, "Hello." to the group. I hope I can
    > >> >> >> > gain
    > >> >> >> > some knowledge from the group's collective input.
    > >> >> >> >
    > >> >> >> > I have a Sony STR-DE635 stereo receiver that will not turn on and
    > >> >> >> > I
    > >> >> >> > would like to investigate into maybe seeing if I can repair it. I
    > >> >> >> > found a set of schematics on this site which I believe will
    > >> >> >> > definitely
    > >> >> >> > help.(http://www.eserviceinfo.com/index.php?what=search2)
    > >> >> >> >
    > >> >> >> > I'm guessing but I think that the problem is related to the power
    > >> >> >> > supply? On p.13 of this .PDF manual it has an A/C and D/C
    > >> >> >> > schematic,
    > >> >> >> > this receiver has a seperate board for each. I probed the A/C
    > >> >> >> > board
    > >> >> >> > and found that it has voltage out to the "Digital" board of a
    > >> >> >> > little
    > >> >> >> > over 12 volts but when I try to test the pins on CNV902 I thought
    > >> >> >> > I
    > >> >> >> > should be getting appx. 110 A/C but only get appx. 2? CNV902 is a
    > >> >> >> > simple 2 wire connector leading directly to a transformer.
    > >> >> >> >
    > >> >> >> > My common sense is telling me that why would I need a
    > >> >> >> > transformaer
    > >> >> >> > the size of Kansas for only 2 volts A/C? So, I'm guessing this
    > >> >> >> > might
    > >> >> >> > have something to do with it? I could be in left field due to my
    > >> >> >> > lack
    > >> >> >> > of knowledge and inexperience, that's why I'm hoping you
    > >> >> >> > guy's/girl's
    > >> >> >> > can shed some light.
    > >> >> >> >
    > >> >> >> > Thanks for any suggestions or hints you can provide.
    ampapa, Oct 4, 2004
    #13
  14. I'd say that's close enough. You're going to have to see that the "5V" line
    makes it to the microprocessor, and at this point you're going to have to
    evaluate the reset line to the micro. Should toggle from ground to 5V when
    you plug in the cord.

    Mark Z.


    "ampapa" <> wrote in message
    news:...
    > I've got 3 readings at the transistor Q1205, the center leg 13.53 and
    > the 2 other legs 6.79 and 6.21 respectively. I think this is wrong,
    > the schematic shows the "base" at 6.5v?
    >
    >
    >
    > "Mark D. Zacharias" <> wrote in message
    > news:<>...
    >> Well, you need to check the standby voltages on the digital board. Q1205
    >> appears to be a 5 volt source.
    >>
    >> Mark Z.
    >>
    >>
    >> "ampapa" <> wrote in message
    >> news:...
    >> > The "standby transformer" is that T902 on the schematic?
    >> >
    >> > I've got 13.5V on the header that leads to the "Digital" board.
    >> >
    >> >
    >> >
    >> > "Mark D. Zacharias" <> wrote in message
    >> > news:<>...
    >> >> Measure from point 12V with respect to ground. I suspect your standby
    >> >> transformer is bad.
    >> >>
    >> >> Mark Z.
    >> >>
    >> >>
    >> >> "ampapa" <> wrote in message
    >> >> news:...
    >> >> > No click when I push the power button and I do have my voltmeter set
    >> >> > to A/C.
    >> >> >
    >> >> > By looking at the schematic am I correct that the transformer should
    >> >> > be seeing appx. 110v? or should I be looking for some other voltage
    >> >> > being delivered to the transformer?
    >> >> >
    >> >> > Also, in order for the A/C board to "enable" the turn-on relay by
    >> >> > the
    >> >> > on/off switch then I should be seeing voltage coming back from the
    >> >> > "Digital" board correct? I see the header that leads to the
    >> >> > "Digital"
    >> >> > board has 4 legs, GND, 12V, P_OFF and P.RY. Are these designations
    >> >> > specific to the industry as to what they represent?
    >> >> >
    >> >> >
    >> >> > Thanks for the help,
    >> >> >
    >> >> >
    >> >> >
    >> >> > "Mark D. Zacharias" <> wrote in message
    >> >> > news:<>...
    >> >> >> If all the fuses are OK, then the power transformer probably isn't
    >> >> >> getting
    >> >> >> voltage from the turn-on relay. Does it click when you press the
    >> >> >> Power
    >> >> >> button? CNV902 gets no AC voltage to speak of til this relay fires.
    >> >> >> (I
    >> >> >> assume your voltmeter is set to measure AC voltage)
    >> >> >>
    >> >> >> Mark Z.
    >> >> >>
    >> >> >>
    >> >> >> "ampapa" <> wrote in message
    >> >> >> news:...
    >> >> >> > Sorry if this is a double post.
    >> >> >> >
    >> >> >> > Mark, are you saying there might be a fuse literaly underneath a
    >> >> >> > circuit board and not necessarily hidden from view by a circuit
    >> >> >> > board?
    >> >> >> > I checked about 5 or 6 fuses in this thing and all checked fine.
    >> >> >> >
    >> >> >> > My biggest problem is that when I read the schematic I can't tell
    >> >> >> > if
    >> >> >> > the transformer is supposed to be getting 110v from the A/C board
    >> >> >> > on
    >> >> >> > CNV902? If it is then I can trace it from there. That's my real
    >> >> >> > dilema.
    >> >> >> >
    >> >> >> > The schematic can be found here
    >> >> >> > (http://www.eserviceinfo.com/index.php?what=search2).
    >> >> >> >
    >> >> >> > Thanks,
    >> >> >> >
    >> >> >> >
    >> >> >> > "Mark D. Zacharias" <> wrote in message
    >> >> >> > news:<>...
    >> >> >> >> These models often have fuses sort of hidden under a circuit
    >> >> >> >> board
    >> >> >> >> attached
    >> >> >> >> to the transformer. If these fuses are blown you probably have a
    >> >> >> >> blown
    >> >> >> >> amp
    >> >> >> >> channel. Sometimes just the output transistors for a given
    >> >> >> >> channel
    >> >> >> >> are
    >> >> >> >> bad,
    >> >> >> >> sometimes there are other small parts bad. Occasionally a
    >> >> >> >> circuit
    >> >> >> >> mod
    >> >> >> >> is
    >> >> >> >> required to lessen the bias at startup.
    >> >> >> >>
    >> >> >> >> Mark Z.
    >> >> >> >>
    >> >> >> >>
    >> >> >> >> "ampapa" <> wrote in message
    >> >> >> >> news:...
    >> >> >> >> > First off I'd like to say, "Hello." to the group. I hope I can
    >> >> >> >> > gain
    >> >> >> >> > some knowledge from the group's collective input.
    >> >> >> >> >
    >> >> >> >> > I have a Sony STR-DE635 stereo receiver that will not turn on
    >> >> >> >> > and
    >> >> >> >> > I
    >> >> >> >> > would like to investigate into maybe seeing if I can repair
    >> >> >> >> > it. I
    >> >> >> >> > found a set of schematics on this site which I believe will
    >> >> >> >> > definitely
    >> >> >> >> > help.(http://www.eserviceinfo.com/index.php?what=search2)
    >> >> >> >> >
    >> >> >> >> > I'm guessing but I think that the problem is related to the
    >> >> >> >> > power
    >> >> >> >> > supply? On p.13 of this .PDF manual it has an A/C and D/C
    >> >> >> >> > schematic,
    >> >> >> >> > this receiver has a seperate board for each. I probed the A/C
    >> >> >> >> > board
    >> >> >> >> > and found that it has voltage out to the "Digital" board of a
    >> >> >> >> > little
    >> >> >> >> > over 12 volts but when I try to test the pins on CNV902 I
    >> >> >> >> > thought
    >> >> >> >> > I
    >> >> >> >> > should be getting appx. 110 A/C but only get appx. 2? CNV902
    >> >> >> >> > is a
    >> >> >> >> > simple 2 wire connector leading directly to a transformer.
    >> >> >> >> >
    >> >> >> >> > My common sense is telling me that why would I need a
    >> >> >> >> > transformaer
    >> >> >> >> > the size of Kansas for only 2 volts A/C? So, I'm guessing this
    >> >> >> >> > might
    >> >> >> >> > have something to do with it? I could be in left field due to
    >> >> >> >> > my
    >> >> >> >> > lack
    >> >> >> >> > of knowledge and inexperience, that's why I'm hoping you
    >> >> >> >> > guy's/girl's
    >> >> >> >> > can shed some light.
    >> >> >> >> >
    >> >> >> >> > Thanks for any suggestions or hints you can provide.
    Mark D. Zacharias, Oct 5, 2004
    #14
  15. P.S.

    If there's any history on this that I should know, now is definitely the
    time to say. For example if there was a lightning strike involved.


    Mark Z.




    "Mark D. Zacharias" <> wrote in message
    news:...
    > I'd say that's close enough. You're going to have to see that the "5V"
    > line makes it to the microprocessor, and at this point you're going to
    > have to evaluate the reset line to the micro. Should toggle from ground to
    > 5V when you plug in the cord.
    >
    > Mark Z.
    >
    >
    > "ampapa" <> wrote in message
    > news:...
    >> I've got 3 readings at the transistor Q1205, the center leg 13.53 and
    >> the 2 other legs 6.79 and 6.21 respectively. I think this is wrong,
    >> the schematic shows the "base" at 6.5v?
    >>
    >>
    >>
    >> "Mark D. Zacharias" <> wrote in message
    >> news:<>...
    >>> Well, you need to check the standby voltages on the digital board. Q1205
    >>> appears to be a 5 volt source.
    >>>
    >>> Mark Z.
    >>>
    >>>
    >>> "ampapa" <> wrote in message
    >>> news:...
    >>> > The "standby transformer" is that T902 on the schematic?
    >>> >
    >>> > I've got 13.5V on the header that leads to the "Digital" board.
    >>> >
    >>> >
    >>> >
    >>> > "Mark D. Zacharias" <> wrote in message
    >>> > news:<>...
    >>> >> Measure from point 12V with respect to ground. I suspect your standby
    >>> >> transformer is bad.
    >>> >>
    >>> >> Mark Z.
    >>> >>
    >>> >>
    >>> >> "ampapa" <> wrote in message
    >>> >> news:...
    >>> >> > No click when I push the power button and I do have my voltmeter
    >>> >> > set
    >>> >> > to A/C.
    >>> >> >
    >>> >> > By looking at the schematic am I correct that the transformer
    >>> >> > should
    >>> >> > be seeing appx. 110v? or should I be looking for some other voltage
    >>> >> > being delivered to the transformer?
    >>> >> >
    >>> >> > Also, in order for the A/C board to "enable" the turn-on relay by
    >>> >> > the
    >>> >> > on/off switch then I should be seeing voltage coming back from the
    >>> >> > "Digital" board correct? I see the header that leads to the
    >>> >> > "Digital"
    >>> >> > board has 4 legs, GND, 12V, P_OFF and P.RY. Are these designations
    >>> >> > specific to the industry as to what they represent?
    >>> >> >
    >>> >> >
    >>> >> > Thanks for the help,
    >>> >> >
    >>> >> >
    >>> >> >
    >>> >> > "Mark D. Zacharias" <> wrote in message
    >>> >> > news:<>...
    >>> >> >> If all the fuses are OK, then the power transformer probably isn't
    >>> >> >> getting
    >>> >> >> voltage from the turn-on relay. Does it click when you press the
    >>> >> >> Power
    >>> >> >> button? CNV902 gets no AC voltage to speak of til this relay
    >>> >> >> fires. (I
    >>> >> >> assume your voltmeter is set to measure AC voltage)
    >>> >> >>
    >>> >> >> Mark Z.
    >>> >> >>
    >>> >> >>
    >>> >> >> "ampapa" <> wrote in message
    >>> >> >> news:...
    >>> >> >> > Sorry if this is a double post.
    >>> >> >> >
    >>> >> >> > Mark, are you saying there might be a fuse literaly underneath a
    >>> >> >> > circuit board and not necessarily hidden from view by a circuit
    >>> >> >> > board?
    >>> >> >> > I checked about 5 or 6 fuses in this thing and all checked fine.
    >>> >> >> >
    >>> >> >> > My biggest problem is that when I read the schematic I can't
    >>> >> >> > tell if
    >>> >> >> > the transformer is supposed to be getting 110v from the A/C
    >>> >> >> > board on
    >>> >> >> > CNV902? If it is then I can trace it from there. That's my real
    >>> >> >> > dilema.
    >>> >> >> >
    >>> >> >> > The schematic can be found here
    >>> >> >> > (http://www.eserviceinfo.com/index.php?what=search2).
    >>> >> >> >
    >>> >> >> > Thanks,
    >>> >> >> >
    >>> >> >> >
    >>> >> >> > "Mark D. Zacharias" <> wrote in message
    >>> >> >> > news:<>...
    >>> >> >> >> These models often have fuses sort of hidden under a circuit
    >>> >> >> >> board
    >>> >> >> >> attached
    >>> >> >> >> to the transformer. If these fuses are blown you probably have
    >>> >> >> >> a
    >>> >> >> >> blown
    >>> >> >> >> amp
    >>> >> >> >> channel. Sometimes just the output transistors for a given
    >>> >> >> >> channel
    >>> >> >> >> are
    >>> >> >> >> bad,
    >>> >> >> >> sometimes there are other small parts bad. Occasionally a
    >>> >> >> >> circuit
    >>> >> >> >> mod
    >>> >> >> >> is
    >>> >> >> >> required to lessen the bias at startup.
    >>> >> >> >>
    >>> >> >> >> Mark Z.
    >>> >> >> >>
    >>> >> >> >>
    >>> >> >> >> "ampapa" <> wrote in message
    >>> >> >> >> news:...
    >>> >> >> >> > First off I'd like to say, "Hello." to the group. I hope I
    >>> >> >> >> > can
    >>> >> >> >> > gain
    >>> >> >> >> > some knowledge from the group's collective input.
    >>> >> >> >> >
    >>> >> >> >> > I have a Sony STR-DE635 stereo receiver that will not turn on
    >>> >> >> >> > and
    >>> >> >> >> > I
    >>> >> >> >> > would like to investigate into maybe seeing if I can repair
    >>> >> >> >> > it. I
    >>> >> >> >> > found a set of schematics on this site which I believe will
    >>> >> >> >> > definitely
    >>> >> >> >> > help.(http://www.eserviceinfo.com/index.php?what=search2)
    >>> >> >> >> >
    >>> >> >> >> > I'm guessing but I think that the problem is related to the
    >>> >> >> >> > power
    >>> >> >> >> > supply? On p.13 of this .PDF manual it has an A/C and D/C
    >>> >> >> >> > schematic,
    >>> >> >> >> > this receiver has a seperate board for each. I probed the A/C
    >>> >> >> >> > board
    >>> >> >> >> > and found that it has voltage out to the "Digital" board of a
    >>> >> >> >> > little
    >>> >> >> >> > over 12 volts but when I try to test the pins on CNV902 I
    >>> >> >> >> > thought
    >>> >> >> >> > I
    >>> >> >> >> > should be getting appx. 110 A/C but only get appx. 2? CNV902
    >>> >> >> >> > is a
    >>> >> >> >> > simple 2 wire connector leading directly to a transformer.
    >>> >> >> >> >
    >>> >> >> >> > My common sense is telling me that why would I need a
    >>> >> >> >> > transformaer
    >>> >> >> >> > the size of Kansas for only 2 volts A/C? So, I'm guessing
    >>> >> >> >> > this
    >>> >> >> >> > might
    >>> >> >> >> > have something to do with it? I could be in left field due to
    >>> >> >> >> > my
    >>> >> >> >> > lack
    >>> >> >> >> > of knowledge and inexperience, that's why I'm hoping you
    >>> >> >> >> > guy's/girl's
    >>> >> >> >> > can shed some light.
    >>> >> >> >> >
    >>> >> >> >> > Thanks for any suggestions or hints you can provide.

    >
    >
    Mark D. Zacharias, Oct 5, 2004
    #15
  16. ampapa

    ampapa Guest

    Mark, thanks for your help.

    "microprocessor" are you referring to the 8 pin IC1206?

    I'm a bit confused at Q1205 the base reading is 13.53v, why? Shouldn't
    that be more like 6.5v?

    One thing that keeps bugging me is the P_RY leg from the A/C board. Is
    this the return leg to the transformer on the A/C board? It's
    currently reading 0v.

    Also, before I flipped the "Digital" board over I noticed some red
    crayon looking markings around the 2 IC's 1205 and 1207. When I
    flipped the board over it looks as though they've been soldered on? I
    don't think this has been worked on, so I thought I would make mention
    seeing as we were in the area and it looked strange.





    "Mark D. Zacharias" <> wrote in message news:<>...
    > I'd say that's close enough. You're going to have to see that the "5V" line
    > makes it to the microprocessor, and at this point you're going to have to
    > evaluate the reset line to the micro. Should toggle from ground to 5V when
    > you plug in the cord.
    >
    > Mark Z.
    >
    >
    > "ampapa" <> wrote in message
    > news:...
    > > I've got 3 readings at the transistor Q1205, the center leg 13.53 and
    > > the 2 other legs 6.79 and 6.21 respectively. I think this is wrong,
    > > the schematic shows the "base" at 6.5v?
    > >
    > >
    > >
    > > "Mark D. Zacharias" <> wrote in message
    > > news:<>...
    > >> Well, you need to check the standby voltages on the digital board. Q1205
    > >> appears to be a 5 volt source.
    > >>
    > >> Mark Z.
    > >>
    > >>
    > >> "ampapa" <> wrote in message
    > >> news:...
    > >> > The "standby transformer" is that T902 on the schematic?
    > >> >
    > >> > I've got 13.5V on the header that leads to the "Digital" board.
    > >> >
    > >> >
    > >> >
    > >> > "Mark D. Zacharias" <> wrote in message
    > >> > news:<>...
    > >> >> Measure from point 12V with respect to ground. I suspect your standby
    > >> >> transformer is bad.
    > >> >>
    > >> >> Mark Z.
    > >> >>
    > >> >>
    > >> >> "ampapa" <> wrote in message
    > >> >> news:...
    > >> >> > No click when I push the power button and I do have my voltmeter set
    > >> >> > to A/C.
    > >> >> >
    > >> >> > By looking at the schematic am I correct that the transformer should
    > >> >> > be seeing appx. 110v? or should I be looking for some other voltage
    > >> >> > being delivered to the transformer?
    > >> >> >
    > >> >> > Also, in order for the A/C board to "enable" the turn-on relay by
    > >> >> > the
    > >> >> > on/off switch then I should be seeing voltage coming back from the
    > >> >> > "Digital" board correct? I see the header that leads to the
    > >> >> > "Digital"
    > >> >> > board has 4 legs, GND, 12V, P_OFF and P.RY. Are these designations
    > >> >> > specific to the industry as to what they represent?
    > >> >> >
    > >> >> >
    > >> >> > Thanks for the help,
    > >> >> >
    > >> >> >
    > >> >> >
    > >> >> > "Mark D. Zacharias" <> wrote in message
    > >> >> > news:<>...
    > >> >> >> If all the fuses are OK, then the power transformer probably isn't
    > >> >> >> getting
    > >> >> >> voltage from the turn-on relay. Does it click when you press the
    > >> >> >> Power
    > >> >> >> button? CNV902 gets no AC voltage to speak of til this relay fires.
    > >> >> >> (I
    > >> >> >> assume your voltmeter is set to measure AC voltage)
    > >> >> >>
    > >> >> >> Mark Z.
    > >> >> >>
    > >> >> >>
    > >> >> >> "ampapa" <> wrote in message
    > >> >> >> news:...
    > >> >> >> > Sorry if this is a double post.
    > >> >> >> >
    > >> >> >> > Mark, are you saying there might be a fuse literaly underneath a
    > >> >> >> > circuit board and not necessarily hidden from view by a circuit
    > >> >> >> > board?
    > >> >> >> > I checked about 5 or 6 fuses in this thing and all checked fine.
    > >> >> >> >
    > >> >> >> > My biggest problem is that when I read the schematic I can't tell
    > >> >> >> > if
    > >> >> >> > the transformer is supposed to be getting 110v from the A/C board
    > >> >> >> > on
    > >> >> >> > CNV902? If it is then I can trace it from there. That's my real
    > >> >> >> > dilema.
    > >> >> >> >
    > >> >> >> > The schematic can be found here
    > >> >> >> > (http://www.eserviceinfo.com/index.php?what=search2).
    > >> >> >> >
    > >> >> >> > Thanks,
    > >> >> >> >
    > >> >> >> >
    > >> >> >> > "Mark D. Zacharias" <> wrote in message
    > >> >> >> > news:<>...
    > >> >> >> >> These models often have fuses sort of hidden under a circuit
    > >> >> >> >> board
    > >> >> >> >> attached
    > >> >> >> >> to the transformer. If these fuses are blown you probably have a
    > >> >> >> >> blown
    > >> >> >> >> amp
    > >> >> >> >> channel. Sometimes just the output transistors for a given
    > >> >> >> >> channel
    > >> >> >> >> are
    > >> >> >> >> bad,
    > >> >> >> >> sometimes there are other small parts bad. Occasionally a
    > >> >> >> >> circuit
    > >> >> >> >> mod
    > >> >> >> >> is
    > >> >> >> >> required to lessen the bias at startup.
    > >> >> >> >>
    > >> >> >> >> Mark Z.
    > >> >> >> >>
    > >> >> >> >>
    > >> >> >> >> "ampapa" <> wrote in message
    > >> >> >> >> news:...
    > >> >> >> >> > First off I'd like to say, "Hello." to the group. I hope I can
    > >> >> >> >> > gain
    > >> >> >> >> > some knowledge from the group's collective input.
    > >> >> >> >> >
    > >> >> >> >> > I have a Sony STR-DE635 stereo receiver that will not turn on
    > >> >> >> >> > and
    > >> >> >> >> > I
    > >> >> >> >> > would like to investigate into maybe seeing if I can repair
    > >> >> >> >> > it. I
    > >> >> >> >> > found a set of schematics on this site which I believe will
    > >> >> >> >> > definitely
    > >> >> >> >> > help.(http://www.eserviceinfo.com/index.php?what=search2)
    > >> >> >> >> >
    > >> >> >> >> > I'm guessing but I think that the problem is related to the
    > >> >> >> >> > power
    > >> >> >> >> > supply? On p.13 of this .PDF manual it has an A/C and D/C
    > >> >> >> >> > schematic,
    > >> >> >> >> > this receiver has a seperate board for each. I probed the A/C
    > >> >> >> >> > board
    > >> >> >> >> > and found that it has voltage out to the "Digital" board of a
    > >> >> >> >> > little
    > >> >> >> >> > over 12 volts but when I try to test the pins on CNV902 I
    > >> >> >> >> > thought
    > >> >> >> >> > I
    > >> >> >> >> > should be getting appx. 110 A/C but only get appx. 2? CNV902
    > >> >> >> >> > is a
    > >> >> >> >> > simple 2 wire connector leading directly to a transformer.
    > >> >> >> >> >
    > >> >> >> >> > My common sense is telling me that why would I need a
    > >> >> >> >> > transformaer
    > >> >> >> >> > the size of Kansas for only 2 volts A/C? So, I'm guessing this
    > >> >> >> >> > might
    > >> >> >> >> > have something to do with it? I could be in left field due to
    > >> >> >> >> > my
    > >> >> >> >> > lack
    > >> >> >> >> > of knowledge and inexperience, that's why I'm hoping you
    > >> >> >> >> > guy's/girl's
    > >> >> >> >> > can shed some light.
    > >> >> >> >> >
    > >> >> >> >> > Thanks for any suggestions or hints you can provide.
    ampapa, Oct 5, 2004
    #16
  17. comments inserted.


    "ampapa" <> wrote in message
    news:...
    > Mark, thanks for your help.
    >
    > "microprocessor" are you referring to the 8 pin IC1206?
    >


    It does appear that the reset pulse comes from IC 1206 pin 8. The
    microprocessor is IC 1201.


    > I'm a bit confused at Q1205 the base reading is 13.53v, why? Shouldn't
    > that be more like 6.5v?


    This is a somewhat unusual circuit,but that voltage certainly looks wrong.
    The transistor Q1205 might be shorted, and / or IC 1206 might be bad.
    Unfortunately, if this places 12 to 13 volts at the cathode of D1211 (1208)
    the microprocessor may very well be fried.


    >
    > One thing that keeps bugging me is the P_RY leg from the A/C board. Is
    > this the return leg to the transformer on the A/C board? It's
    > currently reading 0v.


    This line would probably toggle to 5v or so to turn on the relay if the
    receiver were working properly. It's not, so you see nothing here.


    >
    > Also, before I flipped the "Digital" board over I noticed some red
    > crayon looking markings around the 2 IC's 1205 and 1207. When I
    > flipped the board over it looks as though they've been soldered on? I
    > don't think this has been worked on, so I thought I would make mention
    > seeing as we were in the area and it looked strange.
    >


    Maybe some prior factory rework. I don't think I'd worry about it at this
    point, unless the work looks really sloppy or something's obviously wrong,
    like a wire hanging and shorting against something, etc.

    >
    >

    <snip>


    This repair is going nowhere fast. It would be nice to have another digital
    board to sub.

    Oh, well.


    Mark Z.
    Mark D. Zacharias, Oct 5, 2004
    #17
  18. ampapa

    ampapa Guest

    Mark,

    I spoke with my friend this afternonn and this was a refurb from the
    factory his sister used to work for a Sony call center, but until
    recently the receiver was working fine. He was having a on/off issue,
    no lightning strike.

    I mistyped earlier the 2 IC's that looked like they were replaced are
    IC1205 and IC1501 as well as D1207 and D1206. I tested the diodes with
    my DMM it has a diode test and they appear to be O.K. (tested one
    direction then flipped leads). I'm not sure how to test the IC's?

    I took some readings on the 2 IC's (IC1025 and IC1501) and was getting
    ..25v on leg 1 on both and 0v on the other legs. I also checked IC1206
    and here is how it layed out, definitely out of wack...

    8 - 1.6v
    7 - 1.25v
    6 - 6.76v
    5 - 0
    4 - .35
    3 - 1.83
    2 - 2.37
    1 - 13.53

    I wasn't sure what to test on IC1201 did you want me to look at the
    reset pin 90 for 5v?

    My biggest understanding issue is how do I determine the flow on the
    schematic?

    "This repair is going nowhere fast. It would be nice to have another
    digital
    board to sub."

    My posts take forever to show up on the forum is there a way to speed
    it up??? As far as another board I don't think I can find one? do you
    know anyone selling them, cost, etc.


    AJM,


    "Mark D. Zacharias" <> wrote in message news:<>...
    > P.S.
    >
    > If there's any history on this that I should know, now is definitely the
    > time to say. For example if there was a lightning strike involved.
    >
    >
    > Mark Z.
    >
    >
    >
    >
    > "Mark D. Zacharias" <> wrote in message
    > news:...
    > > I'd say that's close enough. You're going to have to see that the "5V"
    > > line makes it to the microprocessor, and at this point you're going to
    > > have to evaluate the reset line to the micro. Should toggle from ground to
    > > 5V when you plug in the cord.
    > >
    > > Mark Z.
    > >
    > >
    > > "ampapa" <> wrote in message
    > > news:...
    > >> I've got 3 readings at the transistor Q1205, the center leg 13.53 and
    > >> the 2 other legs 6.79 and 6.21 respectively. I think this is wrong,
    > >> the schematic shows the "base" at 6.5v?
    > >>
    > >>
    > >>
    > >> "Mark D. Zacharias" <> wrote in message
    > >> news:<>...
    > >>> Well, you need to check the standby voltages on the digital board. Q1205
    > >>> appears to be a 5 volt source.
    > >>>
    > >>> Mark Z.
    > >>>
    > >>>
    > >>> "ampapa" <> wrote in message
    > >>> news:...
    > >>> > The "standby transformer" is that T902 on the schematic?
    > >>> >
    > >>> > I've got 13.5V on the header that leads to the "Digital" board.
    > >>> >
    > >>> >
    > >>> >
    > >>> > "Mark D. Zacharias" <> wrote in message
    > >>> > news:<>...
    > >>> >> Measure from point 12V with respect to ground. I suspect your standby
    > >>> >> transformer is bad.
    > >>> >>
    > >>> >> Mark Z.
    > >>> >>
    > >>> >>
    > >>> >> "ampapa" <> wrote in message
    > >>> >> news:...
    > >>> >> > No click when I push the power button and I do have my voltmeter
    > >>> >> > set
    > >>> >> > to A/C.
    > >>> >> >
    > >>> >> > By looking at the schematic am I correct that the transformer
    > >>> >> > should
    > >>> >> > be seeing appx. 110v? or should I be looking for some other voltage
    > >>> >> > being delivered to the transformer?
    > >>> >> >
    > >>> >> > Also, in order for the A/C board to "enable" the turn-on relay by
    > >>> >> > the
    > >>> >> > on/off switch then I should be seeing voltage coming back from the
    > >>> >> > "Digital" board correct? I see the header that leads to the
    > >>> >> > "Digital"
    > >>> >> > board has 4 legs, GND, 12V, P_OFF and P.RY. Are these designations
    > >>> >> > specific to the industry as to what they represent?
    > >>> >> >
    > >>> >> >
    > >>> >> > Thanks for the help,
    > >>> >> >
    > >>> >> >
    > >>> >> >
    > >>> >> > "Mark D. Zacharias" <> wrote in message
    > >>> >> > news:<>...
    > >>> >> >> If all the fuses are OK, then the power transformer probably isn't
    > >>> >> >> getting
    > >>> >> >> voltage from the turn-on relay. Does it click when you press the
    > >>> >> >> Power
    > >>> >> >> button? CNV902 gets no AC voltage to speak of til this relay
    > >>> >> >> fires. (I
    > >>> >> >> assume your voltmeter is set to measure AC voltage)
    > >>> >> >>
    > >>> >> >> Mark Z.
    > >>> >> >>
    > >>> >> >>
    > >>> >> >> "ampapa" <> wrote in message
    > >>> >> >> news:...
    > >>> >> >> > Sorry if this is a double post.
    > >>> >> >> >
    > >>> >> >> > Mark, are you saying there might be a fuse literaly underneath a
    > >>> >> >> > circuit board and not necessarily hidden from view by a circuit
    > >>> >> >> > board?
    > >>> >> >> > I checked about 5 or 6 fuses in this thing and all checked fine.
    > >>> >> >> >
    > >>> >> >> > My biggest problem is that when I read the schematic I can't
    > >>> >> >> > tell if
    > >>> >> >> > the transformer is supposed to be getting 110v from the A/C
    > >>> >> >> > board on
    > >>> >> >> > CNV902? If it is then I can trace it from there. That's my real
    > >>> >> >> > dilema.
    > >>> >> >> >
    > >>> >> >> > The schematic can be found here
    > >>> >> >> > (http://www.eserviceinfo.com/index.php?what=search2).
    > >>> >> >> >
    > >>> >> >> > Thanks,
    > >>> >> >> >
    > >>> >> >> >
    > >>> >> >> > "Mark D. Zacharias" <> wrote in message
    > >>> >> >> > news:<>...
    > >>> >> >> >> These models often have fuses sort of hidden under a circuit
    > >>> >> >> >> board
    > >>> >> >> >> attached
    > >>> >> >> >> to the transformer. If these fuses are blown you probably have
    > >>> >> >> >> a
    > >>> >> >> >> blown
    > >>> >> >> >> amp
    > >>> >> >> >> channel. Sometimes just the output transistors for a given
    > >>> >> >> >> channel
    > >>> >> >> >> are
    > >>> >> >> >> bad,
    > >>> >> >> >> sometimes there are other small parts bad. Occasionally a
    > >>> >> >> >> circuit
    > >>> >> >> >> mod
    > >>> >> >> >> is
    > >>> >> >> >> required to lessen the bias at startup.
    > >>> >> >> >>
    > >>> >> >> >> Mark Z.
    > >>> >> >> >>
    > >>> >> >> >>
    > >>> >> >> >> "ampapa" <> wrote in message
    > >>> >> >> >> news:...
    > >>> >> >> >> > First off I'd like to say, "Hello." to the group. I hope I
    > >>> >> >> >> > can
    > >>> >> >> >> > gain
    > >>> >> >> >> > some knowledge from the group's collective input.
    > >>> >> >> >> >
    > >>> >> >> >> > I have a Sony STR-DE635 stereo receiver that will not turn on
    > >>> >> >> >> > and
    > >>> >> >> >> > I
    > >>> >> >> >> > would like to investigate into maybe seeing if I can repair
    > >>> >> >> >> > it. I
    > >>> >> >> >> > found a set of schematics on this site which I believe will
    > >>> >> >> >> > definitely
    > >>> >> >> >> > help.(http://www.eserviceinfo.com/index.php?what=search2)
    > >>> >> >> >> >
    > >>> >> >> >> > I'm guessing but I think that the problem is related to the
    > >>> >> >> >> > power
    > >>> >> >> >> > supply? On p.13 of this .PDF manual it has an A/C and D/C
    > >>> >> >> >> > schematic,
    > >>> >> >> >> > this receiver has a seperate board for each. I probed the A/C
    > >>> >> >> >> > board
    > >>> >> >> >> > and found that it has voltage out to the "Digital" board of a
    > >>> >> >> >> > little
    > >>> >> >> >> > over 12 volts but when I try to test the pins on CNV902 I
    > >>> >> >> >> > thought
    > >>> >> >> >> > I
    > >>> >> >> >> > should be getting appx. 110 A/C but only get appx. 2? CNV902
    > >>> >> >> >> > is a
    > >>> >> >> >> > simple 2 wire connector leading directly to a transformer.
    > >>> >> >> >> >
    > >>> >> >> >> > My common sense is telling me that why would I need a
    > >>> >> >> >> > transformaer
    > >>> >> >> >> > the size of Kansas for only 2 volts A/C? So, I'm guessing
    > >>> >> >> >> > this
    > >>> >> >> >> > might
    > >>> >> >> >> > have something to do with it? I could be in left field due to
    > >>> >> >> >> > my
    > >>> >> >> >> > lack
    > >>> >> >> >> > of knowledge and inexperience, that's why I'm hoping you
    > >>> >> >> >> > guy's/girl's
    > >>> >> >> >> > can shed some light.
    > >>> >> >> >> >
    > >>> >> >> >> > Thanks for any suggestions or hints you can provide.

    > >
    > >
    ampapa, Oct 6, 2004
    #18
  19. I'm going to digest this for a bit and will post back later.

    Meanwhile, if you're posting through Google, they only add posts once or
    twice a day.


    Mark Z.


    "ampapa" <> wrote in message
    news:...
    > Mark,
    >
    > I spoke with my friend this afternonn and this was a refurb from the
    > factory his sister used to work for a Sony call center, but until
    > recently the receiver was working fine. He was having a on/off issue,
    > no lightning strike.
    >
    > I mistyped earlier the 2 IC's that looked like they were replaced are
    > IC1205 and IC1501 as well as D1207 and D1206. I tested the diodes with
    > my DMM it has a diode test and they appear to be O.K. (tested one
    > direction then flipped leads). I'm not sure how to test the IC's?
    >
    > I took some readings on the 2 IC's (IC1025 and IC1501) and was getting
    > .25v on leg 1 on both and 0v on the other legs. I also checked IC1206
    > and here is how it layed out, definitely out of wack...
    >
    > 8 - 1.6v
    > 7 - 1.25v
    > 6 - 6.76v
    > 5 - 0
    > 4 - .35
    > 3 - 1.83
    > 2 - 2.37
    > 1 - 13.53
    >
    > I wasn't sure what to test on IC1201 did you want me to look at the
    > reset pin 90 for 5v?
    >
    > My biggest understanding issue is how do I determine the flow on the
    > schematic?
    >
    > "This repair is going nowhere fast. It would be nice to have another
    > digital
    > board to sub."
    >
    > My posts take forever to show up on the forum is there a way to speed
    > it up??? As far as another board I don't think I can find one? do you
    > know anyone selling them, cost, etc.
    >
    >
    > AJM,
    >
    >
    > "Mark D. Zacharias" <> wrote in message
    > news:<>...
    >> P.S.
    >>
    >> If there's any history on this that I should know, now is definitely the
    >> time to say. For example if there was a lightning strike involved.
    >>
    >>
    >> Mark Z.
    >>
    >>
    >>
    >>
    >> "Mark D. Zacharias" <> wrote in message
    >> news:...
    >> > I'd say that's close enough. You're going to have to see that the "5V"
    >> > line makes it to the microprocessor, and at this point you're going to
    >> > have to evaluate the reset line to the micro. Should toggle from ground
    >> > to
    >> > 5V when you plug in the cord.
    >> >
    >> > Mark Z.
    >> >
    >> >
    >> > "ampapa" <> wrote in message
    >> > news:...
    >> >> I've got 3 readings at the transistor Q1205, the center leg 13.53 and
    >> >> the 2 other legs 6.79 and 6.21 respectively. I think this is wrong,
    >> >> the schematic shows the "base" at 6.5v?
    >> >>
    >> >>
    >> >>
    >> >> "Mark D. Zacharias" <> wrote in message
    >> >> news:<>...
    >> >>> Well, you need to check the standby voltages on the digital board.
    >> >>> Q1205
    >> >>> appears to be a 5 volt source.
    >> >>>
    >> >>> Mark Z.
    >> >>>
    >> >>>
    >> >>> "ampapa" <> wrote in message
    >> >>> news:...
    >> >>> > The "standby transformer" is that T902 on the schematic?
    >> >>> >
    >> >>> > I've got 13.5V on the header that leads to the "Digital" board.
    >> >>> >
    >> >>> >
    >> >>> >
    >> >>> > "Mark D. Zacharias" <> wrote in message
    >> >>> > news:<>...
    >> >>> >> Measure from point 12V with respect to ground. I suspect your
    >> >>> >> standby
    >> >>> >> transformer is bad.
    >> >>> >>
    >> >>> >> Mark Z.
    >> >>> >>
    >> >>> >>
    >> >>> >> "ampapa" <> wrote in message
    >> >>> >> news:...
    >> >>> >> > No click when I push the power button and I do have my voltmeter
    >> >>> >> > set
    >> >>> >> > to A/C.
    >> >>> >> >
    >> >>> >> > By looking at the schematic am I correct that the transformer
    >> >>> >> > should
    >> >>> >> > be seeing appx. 110v? or should I be looking for some other
    >> >>> >> > voltage
    >> >>> >> > being delivered to the transformer?
    >> >>> >> >
    >> >>> >> > Also, in order for the A/C board to "enable" the turn-on relay
    >> >>> >> > by
    >> >>> >> > the
    >> >>> >> > on/off switch then I should be seeing voltage coming back from
    >> >>> >> > the
    >> >>> >> > "Digital" board correct? I see the header that leads to the
    >> >>> >> > "Digital"
    >> >>> >> > board has 4 legs, GND, 12V, P_OFF and P.RY. Are these
    >> >>> >> > designations
    >> >>> >> > specific to the industry as to what they represent?
    >> >>> >> >
    >> >>> >> >
    >> >>> >> > Thanks for the help,
    >> >>> >> >
    >> >>> >> >
    >> >>> >> >
    >> >>> >> > "Mark D. Zacharias" <> wrote in message
    >> >>> >> > news:<>...
    >> >>> >> >> If all the fuses are OK, then the power transformer probably
    >> >>> >> >> isn't
    >> >>> >> >> getting
    >> >>> >> >> voltage from the turn-on relay. Does it click when you press
    >> >>> >> >> the
    >> >>> >> >> Power
    >> >>> >> >> button? CNV902 gets no AC voltage to speak of til this relay
    >> >>> >> >> fires. (I
    >> >>> >> >> assume your voltmeter is set to measure AC voltage)
    >> >>> >> >>
    >> >>> >> >> Mark Z.
    >> >>> >> >>
    >> >>> >> >>
    >> >>> >> >> "ampapa" <> wrote in message
    >> >>> >> >> news:...
    >> >>> >> >> > Sorry if this is a double post.
    >> >>> >> >> >
    >> >>> >> >> > Mark, are you saying there might be a fuse literaly
    >> >>> >> >> > underneath a
    >> >>> >> >> > circuit board and not necessarily hidden from view by a
    >> >>> >> >> > circuit
    >> >>> >> >> > board?
    >> >>> >> >> > I checked about 5 or 6 fuses in this thing and all checked
    >> >>> >> >> > fine.
    >> >>> >> >> >
    >> >>> >> >> > My biggest problem is that when I read the schematic I can't
    >> >>> >> >> > tell if
    >> >>> >> >> > the transformer is supposed to be getting 110v from the A/C
    >> >>> >> >> > board on
    >> >>> >> >> > CNV902? If it is then I can trace it from there. That's my
    >> >>> >> >> > real
    >> >>> >> >> > dilema.
    >> >>> >> >> >
    >> >>> >> >> > The schematic can be found here
    >> >>> >> >> > (http://www.eserviceinfo.com/index.php?what=search2).
    >> >>> >> >> >
    >> >>> >> >> > Thanks,
    >> >>> >> >> >
    >> >>> >> >> >
    >> >>> >> >> > "Mark D. Zacharias" <> wrote in message
    >> >>> >> >> > news:<>...
    >> >>> >> >> >> These models often have fuses sort of hidden under a circuit
    >> >>> >> >> >> board
    >> >>> >> >> >> attached
    >> >>> >> >> >> to the transformer. If these fuses are blown you probably
    >> >>> >> >> >> have
    >> >>> >> >> >> a
    >> >>> >> >> >> blown
    >> >>> >> >> >> amp
    >> >>> >> >> >> channel. Sometimes just the output transistors for a given
    >> >>> >> >> >> channel
    >> >>> >> >> >> are
    >> >>> >> >> >> bad,
    >> >>> >> >> >> sometimes there are other small parts bad. Occasionally a
    >> >>> >> >> >> circuit
    >> >>> >> >> >> mod
    >> >>> >> >> >> is
    >> >>> >> >> >> required to lessen the bias at startup.
    >> >>> >> >> >>
    >> >>> >> >> >> Mark Z.
    >> >>> >> >> >>
    >> >>> >> >> >>
    >> >>> >> >> >> "ampapa" <> wrote in message
    >> >>> >> >> >> news:...
    >> >>> >> >> >> > First off I'd like to say, "Hello." to the group. I hope I
    >> >>> >> >> >> > can
    >> >>> >> >> >> > gain
    >> >>> >> >> >> > some knowledge from the group's collective input.
    >> >>> >> >> >> >
    >> >>> >> >> >> > I have a Sony STR-DE635 stereo receiver that will not turn
    >> >>> >> >> >> > on
    >> >>> >> >> >> > and
    >> >>> >> >> >> > I
    >> >>> >> >> >> > would like to investigate into maybe seeing if I can
    >> >>> >> >> >> > repair
    >> >>> >> >> >> > it. I
    >> >>> >> >> >> > found a set of schematics on this site which I believe
    >> >>> >> >> >> > will
    >> >>> >> >> >> > definitely
    >> >>> >> >> >> > help.(http://www.eserviceinfo.com/index.php?what=search2)
    >> >>> >> >> >> >
    >> >>> >> >> >> > I'm guessing but I think that the problem is related to
    >> >>> >> >> >> > the
    >> >>> >> >> >> > power
    >> >>> >> >> >> > supply? On p.13 of this .PDF manual it has an A/C and D/C
    >> >>> >> >> >> > schematic,
    >> >>> >> >> >> > this receiver has a seperate board for each. I probed the
    >> >>> >> >> >> > A/C
    >> >>> >> >> >> > board
    >> >>> >> >> >> > and found that it has voltage out to the "Digital" board
    >> >>> >> >> >> > of a
    >> >>> >> >> >> > little
    >> >>> >> >> >> > over 12 volts but when I try to test the pins on CNV902 I
    >> >>> >> >> >> > thought
    >> >>> >> >> >> > I
    >> >>> >> >> >> > should be getting appx. 110 A/C but only get appx. 2?
    >> >>> >> >> >> > CNV902
    >> >>> >> >> >> > is a
    >> >>> >> >> >> > simple 2 wire connector leading directly to a transformer.
    >> >>> >> >> >> >
    >> >>> >> >> >> > My common sense is telling me that why would I need a
    >> >>> >> >> >> > transformaer
    >> >>> >> >> >> > the size of Kansas for only 2 volts A/C? So, I'm guessing
    >> >>> >> >> >> > this
    >> >>> >> >> >> > might
    >> >>> >> >> >> > have something to do with it? I could be in left field due
    >> >>> >> >> >> > to
    >> >>> >> >> >> > my
    >> >>> >> >> >> > lack
    >> >>> >> >> >> > of knowledge and inexperience, that's why I'm hoping you
    >> >>> >> >> >> > guy's/girl's
    >> >>> >> >> >> > can shed some light.
    >> >>> >> >> >> >
    >> >>> >> >> >> > Thanks for any suggestions or hints you can provide.
    >> >
    >> >
    Mark D. Zacharias, Oct 6, 2004
    #19
  20. ampapa

    ampapa Guest

    How can I post quicker so we can respond faster?

    "Mark D. Zacharias" <> wrote in message news:<>...
    > I'm going to digest this for a bit and will post back later.
    >
    > Meanwhile, if you're posting through Google, they only add posts once or
    > twice a day.
    >
    >
    > Mark Z.
    >
    >
    > "ampapa" <> wrote in message
    > news:...
    > > Mark,
    > >
    > > I spoke with my friend this afternonn and this was a refurb from the
    > > factory his sister used to work for a Sony call center, but until
    > > recently the receiver was working fine. He was having a on/off issue,
    > > no lightning strike.
    > >
    > > I mistyped earlier the 2 IC's that looked like they were replaced are
    > > IC1205 and IC1501 as well as D1207 and D1206. I tested the diodes with
    > > my DMM it has a diode test and they appear to be O.K. (tested one
    > > direction then flipped leads). I'm not sure how to test the IC's?
    > >
    > > I took some readings on the 2 IC's (IC1025 and IC1501) and was getting
    > > .25v on leg 1 on both and 0v on the other legs. I also checked IC1206
    > > and here is how it layed out, definitely out of wack...
    > >
    > > 8 - 1.6v
    > > 7 - 1.25v
    > > 6 - 6.76v
    > > 5 - 0
    > > 4 - .35
    > > 3 - 1.83
    > > 2 - 2.37
    > > 1 - 13.53
    > >
    > > I wasn't sure what to test on IC1201 did you want me to look at the
    > > reset pin 90 for 5v?
    > >
    > > My biggest understanding issue is how do I determine the flow on the
    > > schematic?
    > >
    > > "This repair is going nowhere fast. It would be nice to have another
    > > digital
    > > board to sub."
    > >
    > > My posts take forever to show up on the forum is there a way to speed
    > > it up??? As far as another board I don't think I can find one? do you
    > > know anyone selling them, cost, etc.
    > >
    > >
    > > AJM,
    > >
    > >
    > > "Mark D. Zacharias" <> wrote in message
    > > news:<>...
    > >> P.S.
    > >>
    > >> If there's any history on this that I should know, now is definitely the
    > >> time to say. For example if there was a lightning strike involved.
    > >>
    > >>
    > >> Mark Z.
    > >>
    > >>
    > >>
    > >>
    > >> "Mark D. Zacharias" <> wrote in message
    > >> news:...
    > >> > I'd say that's close enough. You're going to have to see that the "5V"
    > >> > line makes it to the microprocessor, and at this point you're going to
    > >> > have to evaluate the reset line to the micro. Should toggle from ground
    > >> > to
    > >> > 5V when you plug in the cord.
    > >> >
    > >> > Mark Z.
    > >> >
    > >> >
    > >> > "ampapa" <> wrote in message
    > >> > news:...
    > >> >> I've got 3 readings at the transistor Q1205, the center leg 13.53 and
    > >> >> the 2 other legs 6.79 and 6.21 respectively. I think this is wrong,
    > >> >> the schematic shows the "base" at 6.5v?
    > >> >>
    > >> >>
    > >> >>
    > >> >> "Mark D. Zacharias" <> wrote in message
    > >> >> news:<>...
    > >> >>> Well, you need to check the standby voltages on the digital board.
    > >> >>> Q1205
    > >> >>> appears to be a 5 volt source.
    > >> >>>
    > >> >>> Mark Z.
    > >> >>>
    > >> >>>
    > >> >>> "ampapa" <> wrote in message
    > >> >>> news:...
    > >> >>> > The "standby transformer" is that T902 on the schematic?
    > >> >>> >
    > >> >>> > I've got 13.5V on the header that leads to the "Digital" board.
    > >> >>> >
    > >> >>> >
    > >> >>> >
    > >> >>> > "Mark D. Zacharias" <> wrote in message
    > >> >>> > news:<>...
    > >> >>> >> Measure from point 12V with respect to ground. I suspect your
    > >> >>> >> standby
    > >> >>> >> transformer is bad.
    > >> >>> >>
    > >> >>> >> Mark Z.
    > >> >>> >>
    > >> >>> >>
    > >> >>> >> "ampapa" <> wrote in message
    > >> >>> >> news:...
    > >> >>> >> > No click when I push the power button and I do have my voltmeter
    > >> >>> >> > set
    > >> >>> >> > to A/C.
    > >> >>> >> >
    > >> >>> >> > By looking at the schematic am I correct that the transformer
    > >> >>> >> > should
    > >> >>> >> > be seeing appx. 110v? or should I be looking for some other
    > >> >>> >> > voltage
    > >> >>> >> > being delivered to the transformer?
    > >> >>> >> >
    > >> >>> >> > Also, in order for the A/C board to "enable" the turn-on relay
    > >> >>> >> > by
    > >> >>> >> > the
    > >> >>> >> > on/off switch then I should be seeing voltage coming back from
    > >> >>> >> > the
    > >> >>> >> > "Digital" board correct? I see the header that leads to the
    > >> >>> >> > "Digital"
    > >> >>> >> > board has 4 legs, GND, 12V, P_OFF and P.RY. Are these
    > >> >>> >> > designations
    > >> >>> >> > specific to the industry as to what they represent?
    > >> >>> >> >
    > >> >>> >> >
    > >> >>> >> > Thanks for the help,
    > >> >>> >> >
    > >> >>> >> >
    > >> >>> >> >
    > >> >>> >> > "Mark D. Zacharias" <> wrote in message
    > >> >>> >> > news:<>...
    > >> >>> >> >> If all the fuses are OK, then the power transformer probably
    > >> >>> >> >> isn't
    > >> >>> >> >> getting
    > >> >>> >> >> voltage from the turn-on relay. Does it click when you press
    > >> >>> >> >> the
    > >> >>> >> >> Power
    > >> >>> >> >> button? CNV902 gets no AC voltage to speak of til this relay
    > >> >>> >> >> fires. (I
    > >> >>> >> >> assume your voltmeter is set to measure AC voltage)
    > >> >>> >> >>
    > >> >>> >> >> Mark Z.
    > >> >>> >> >>
    > >> >>> >> >>
    > >> >>> >> >> "ampapa" <> wrote in message
    > >> >>> >> >> news:...
    > >> >>> >> >> > Sorry if this is a double post.
    > >> >>> >> >> >
    > >> >>> >> >> > Mark, are you saying there might be a fuse literaly
    > >> >>> >> >> > underneath a
    > >> >>> >> >> > circuit board and not necessarily hidden from view by a
    > >> >>> >> >> > circuit
    > >> >>> >> >> > board?
    > >> >>> >> >> > I checked about 5 or 6 fuses in this thing and all checked
    > >> >>> >> >> > fine.
    > >> >>> >> >> >
    > >> >>> >> >> > My biggest problem is that when I read the schematic I can't
    > >> >>> >> >> > tell if
    > >> >>> >> >> > the transformer is supposed to be getting 110v from the A/C
    > >> >>> >> >> > board on
    > >> >>> >> >> > CNV902? If it is then I can trace it from there. That's my
    > >> >>> >> >> > real
    > >> >>> >> >> > dilema.
    > >> >>> >> >> >
    > >> >>> >> >> > The schematic can be found here
    > >> >>> >> >> > (http://www.eserviceinfo.com/index.php?what=search2).
    > >> >>> >> >> >
    > >> >>> >> >> > Thanks,
    > >> >>> >> >> >
    > >> >>> >> >> >
    > >> >>> >> >> > "Mark D. Zacharias" <> wrote in message
    > >> >>> >> >> > news:<>...
    > >> >>> >> >> >> These models often have fuses sort of hidden under a circuit
    > >> >>> >> >> >> board
    > >> >>> >> >> >> attached
    > >> >>> >> >> >> to the transformer. If these fuses are blown you probably
    > >> >>> >> >> >> have
    > >> >>> >> >> >> a
    > >> >>> >> >> >> blown
    > >> >>> >> >> >> amp
    > >> >>> >> >> >> channel. Sometimes just the output transistors for a given
    > >> >>> >> >> >> channel
    > >> >>> >> >> >> are
    > >> >>> >> >> >> bad,
    > >> >>> >> >> >> sometimes there are other small parts bad. Occasionally a
    > >> >>> >> >> >> circuit
    > >> >>> >> >> >> mod
    > >> >>> >> >> >> is
    > >> >>> >> >> >> required to lessen the bias at startup.
    > >> >>> >> >> >>
    > >> >>> >> >> >> Mark Z.
    > >> >>> >> >> >>
    > >> >>> >> >> >>
    > >> >>> >> >> >> "ampapa" <> wrote in message
    > >> >>> >> >> >> news:...
    > >> >>> >> >> >> > First off I'd like to say, "Hello." to the group. I hope I
    > >> >>> >> >> >> > can
    > >> >>> >> >> >> > gain
    > >> >>> >> >> >> > some knowledge from the group's collective input.
    > >> >>> >> >> >> >
    > >> >>> >> >> >> > I have a Sony STR-DE635 stereo receiver that will not turn
    > >> >>> >> >> >> > on
    > >> >>> >> >> >> > and
    > >> >>> >> >> >> > I
    > >> >>> >> >> >> > would like to investigate into maybe seeing if I can
    > >> >>> >> >> >> > repair
    > >> >>> >> >> >> > it. I
    > >> >>> >> >> >> > found a set of schematics on this site which I believe
    > >> >>> >> >> >> > will
    > >> >>> >> >> >> > definitely
    > >> >>> >> >> >> > help.(http://www.eserviceinfo.com/index.php?what=search2)
    > >> >>> >> >> >> >
    > >> >>> >> >> >> > I'm guessing but I think that the problem is related to
    > >> >>> >> >> >> > the
    > >> >>> >> >> >> > power
    > >> >>> >> >> >> > supply? On p.13 of this .PDF manual it has an A/C and D/C
    > >> >>> >> >> >> > schematic,
    > >> >>> >> >> >> > this receiver has a seperate board for each. I probed the
    > >> >>> >> >> >> > A/C
    > >> >>> >> >> >> > board
    > >> >>> >> >> >> > and found that it has voltage out to the "Digital" board
    > >> >>> >> >> >> > of a
    > >> >>> >> >> >> > little
    > >> >>> >> >> >> > over 12 volts but when I try to test the pins on CNV902 I
    > >> >>> >> >> >> > thought
    > >> >>> >> >> >> > I
    > >> >>> >> >> >> > should be getting appx. 110 A/C but only get appx. 2?
    > >> >>> >> >> >> > CNV902
    > >> >>> >> >> >> > is a
    > >> >>> >> >> >> > simple 2 wire connector leading directly to a transformer.
    > >> >>> >> >> >> >
    > >> >>> >> >> >> > My common sense is telling me that why would I need a
    > >> >>> >> >> >> > transformaer
    > >> >>> >> >> >> > the size of Kansas for only 2 volts A/C? So, I'm guessing
    > >> >>> >> >> >> > this
    > >> >>> >> >> >> > might
    > >> >>> >> >> >> > have something to do with it? I could be in left field due
    > >> >>> >> >> >> > to
    > >> >>> >> >> >> > my
    > >> >>> >> >> >> > lack
    > >> >>> >> >> >> > of knowledge and inexperience, that's why I'm hoping you
    > >> >>> >> >> >> > guy's/girl's
    > >> >>> >> >> >> > can shed some light.
    > >> >>> >> >> >> >
    > >> >>> >> >> >> > Thanks for any suggestions or hints you can provide.
    > >> >
    > >> >
    ampapa, Oct 6, 2004
    #20
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