blown fuse on fairly new Yamaha HTR 5790 receiver

Discussion in 'Electronic Repair' started by floydturbo@gmail.com, Oct 10, 2007.

  1. Guest

    One of the two main fuses blows instantly as soon as power is applied
    to receiver. I checked the main power supply caps 2@10,000uf and they
    were ok. I also checked the bridge rectifier and it was ok. When I
    remove the two power leads to the transformer it does not blow fuse.
    The main windings of the transformer are 1.0 ohm. The output
    transistors are each about 800 ohms at the speaker terminal (prior to
    relay).

    What else to check?????


    Thanks!!
     
    , Oct 10, 2007
    #1
    1. Advertising

  2. hr(bob) Guest

    On Oct 9, 7:27 pm, wrote:
    > One of the two main fuses blows instantly as soon as power is applied
    > to receiver. I checked the main power supply caps 2@10,000uf and they
    > were ok. I also checked the bridge rectifier and it was ok. When I
    > remove the two power leads to the transformer it does not blow fuse.
    > The main windings of the transformer are 1.0 ohm. The output
    > transistors are each about 800 ohms at the speaker terminal (prior to
    > relay).
    >
    > What else to check?????
    >
    > Thanks!!


    Disconnect all loads from the electrolytics, so you just have the
    transformer, diodes and capacitors in the circuit and see what
    happens. The diodes may test ok but break down under higher voltage
    than your tester applies.

    H. R. (Bob) Hofmann
     
    hr(bob) , Oct 10, 2007
    #2
    1. Advertising

  3. Jamie Guest

    wrote:

    > One of the two main fuses blows instantly as soon as power is applied
    > to receiver. I checked the main power supply caps 2@10,000uf and they
    > were ok. I also checked the bridge rectifier and it was ok. When I
    > remove the two power leads to the transformer it does not blow fuse.
    > The main windings of the transformer are 1.0 ohm. The output
    > transistors are each about 800 ohms at the speaker terminal (prior to
    > relay).
    >
    > What else to check?????
    >
    >
    > Thanks!!
    >


    To save your self some fuses and hassles, find
    your self a high wattage incandescent lamp rated
    for the line voltage your using (120v 200W) for
    example. Use that in place of the fuse until you can
    removed the solid short.
    WHen you say you removed the main windings? I can
    only assume you're referring to the primary side of the
    xformer?. If so, how about disconnecting the secondary
    sides?
    You may want to perform a short test to ground to see if you have
    a shorted xformer. The preferred method is to use a megga meter.

    Usual causes are arc's from lightning storms or over heating of the
    enamel if you do find a short to ground.
    --
    If disconnecting the secondary from the bridge removes the short,
    then try disconnecting the output supply that goes from the bridge and
    caps into the amp.

    Also, you may have a time delayed on or soft start circuit that may not
    be soft starting.

    P.S.
    Because a CAP or bridge test ok at DMM voltage levels does not mean
    they are good.


    --
    "I'm never wrong, once i thought i was, but was mistaken"
    Real Programmers Do things like this.
    http://webpages.charter.net/jamie_5
     
    Jamie, Oct 10, 2007
    #3
  4. Arfa Daily Guest

    "Jamie" <> wrote in message
    news:vpVOi.59$...
    > wrote:
    >
    >> One of the two main fuses blows instantly as soon as power is applied
    >> to receiver. I checked the main power supply caps 2@10,000uf and they
    >> were ok. I also checked the bridge rectifier and it was ok. When I
    >> remove the two power leads to the transformer it does not blow fuse.
    >> The main windings of the transformer are 1.0 ohm. The output
    >> transistors are each about 800 ohms at the speaker terminal (prior to
    >> relay).
    >>
    >> What else to check?????
    >>
    >>
    >> Thanks!!
    >>

    >
    > To save your self some fuses and hassles, find
    > your self a high wattage incandescent lamp rated
    > for the line voltage your using (120v 200W) for
    > example. Use that in place of the fuse until you can
    > removed the solid short.
    > WHen you say you removed the main windings? I can
    > only assume you're referring to the primary side of the
    > xformer?. If so, how about disconnecting the secondary
    > sides?
    > You may want to perform a short test to ground to see if you have
    > a shorted xformer. The preferred method is to use a megga meter.
    >
    > Usual causes are arc's from lightning storms or over heating of the
    > enamel if you do find a short to ground.
    > --
    > If disconnecting the secondary from the bridge removes the short,
    > then try disconnecting the output supply that goes from the bridge and
    > caps into the amp.
    >
    > Also, you may have a time delayed on or soft start circuit that may not
    > be soft starting.
    >
    > P.S.
    > Because a CAP or bridge test ok at DMM voltage levels does not mean
    > they are good.
    >
    >
    > --
    > "I'm never wrong, once i thought i was, but was mistaken"
    > Real Programmers Do things like this.
    > http://webpages.charter.net/jamie_5
    >


    If you can lay hands on a variac, use that to power the unit. This kind of
    fault then becomes a breeze to locate (the basic cause of). If it turns out
    to be related to the output stages - and I'm not quite sure of what you are
    measuring to come up with your "800 ohms" figure - then how simple or not
    the *actual* problem is, is a whole new ball game with DC coupled amps like
    this ...

    Arfa
     
    Arfa Daily, Oct 10, 2007
    #4
  5. "Arfa Daily" <> wrote in message
    news:7C1Pi.12361$...
    >
    > "Jamie" <> wrote in
    > message news:vpVOi.59$...
    >> wrote:
    >>
    >>> One of the two main fuses blows instantly as soon as power is applied
    >>> to receiver. I checked the main power supply caps 2@10,000uf and they
    >>> were ok. I also checked the bridge rectifier and it was ok. When I
    >>> remove the two power leads to the transformer it does not blow fuse.
    >>> The main windings of the transformer are 1.0 ohm. The output
    >>> transistors are each about 800 ohms at the speaker terminal (prior to
    >>> relay).
    >>>
    >>> What else to check?????
    >>>
    >>>
    >>> Thanks!!
    >>>

    >>
    >> To save your self some fuses and hassles, find
    >> your self a high wattage incandescent lamp rated
    >> for the line voltage your using (120v 200W) for
    >> example. Use that in place of the fuse until you can
    >> removed the solid short.
    >> WHen you say you removed the main windings? I can
    >> only assume you're referring to the primary side of the
    >> xformer?. If so, how about disconnecting the secondary
    >> sides?
    >> You may want to perform a short test to ground to see if you have
    >> a shorted xformer. The preferred method is to use a megga meter.
    >>
    >> Usual causes are arc's from lightning storms or over heating of the
    >> enamel if you do find a short to ground.
    >> --
    >> If disconnecting the secondary from the bridge removes the short,
    >> then try disconnecting the output supply that goes from the bridge and
    >> caps into the amp.
    >>
    >> Also, you may have a time delayed on or soft start circuit that may not
    >> be soft starting.
    >>
    >> P.S.
    >> Because a CAP or bridge test ok at DMM voltage levels does not mean
    >> they are good.
    >>
    >>
    >> --
    >> "I'm never wrong, once i thought i was, but was mistaken"
    >> Real Programmers Do things like this.
    >> http://webpages.charter.net/jamie_5
    >>

    >
    > If you can lay hands on a variac, use that to power the unit. This kind of
    > fault then becomes a breeze to locate (the basic cause of). If it turns
    > out to be related to the output stages - and I'm not quite sure of what
    > you are measuring to come up with your "800 ohms" figure - then how simple
    > or not the *actual* problem is, is a whole new ball game with DC coupled
    > amps like this ...
    >
    > Arfa
    >


    I'm going to assume the typical.

    1. An amp channel is blown.
    2. The associated emitter resistor is not blown yet since the fuse blows.
    3. You can measure from the center leg of each emitter resistor to the
    collector tabs of the associated output transistors.
    4. When you find a channel where the emitter is shorted to one or both
    collectors, you've found your blown channel.
    5. There are often other parts bad as well, though the Yamaha amp channels
    are pretty easy. Often there is a resistor between the driver transistors
    which is burned - usually 220 ohms, and of course the drivers are suspect,
    the bias transistor could be bad OR HAVE BAD SOLDER CONNECTIONS which caused
    the failure in the first place, and there could be another resistor bad
    which feeds the B+ or B- voltage to a driver - usually 47 ohms.


    Mark Z.
     
    Mark D. Zacharias, Oct 10, 2007
    #5
  6. Guest

    On Oct 10, 4:15 am, "Mark D. Zacharias" <>
    wrote:
    > "Arfa Daily" <> wrote in message
    >
    > news:7C1Pi.12361$...
    >
    >
    >
    >
    >
    >
    >
    > > "Jamie" <> wrote in
    > > messagenews:vpVOi.59$...
    > >> wrote:

    >
    > >>> One of the two main fuses blows instantly as soon as power is applied
    > >>> to receiver. I checked the main power supply caps 2@10,000uf and they
    > >>> were ok. I also checked the bridge rectifier and it was ok. When I
    > >>> remove the two power leads to the transformer it does not blow fuse.
    > >>> The main windings of the transformer are 1.0 ohm. The output
    > >>> transistors are each about 800 ohms at the speaker terminal (prior to
    > >>> relay).

    >
    > >>> What else to check?????

    >
    > >>> Thanks!!

    >
    > >> To save your self some fuses and hassles, find
    > >> your self a high wattage incandescent lamp rated
    > >> for the line voltage your using (120v 200W) for
    > >> example. Use that in place of the fuse until you can
    > >> removed the solid short.
    > >> WHen you say you removed the main windings? I can
    > >> only assume you're referring to the primary side of the
    > >> xformer?. If so, how about disconnecting the secondary
    > >> sides?
    > >> You may want to perform a short test to ground to see if you have
    > >> a shorted xformer. The preferred method is to use a megga meter.

    >
    > >> Usual causes are arc's from lightning storms or over heating of the
    > >> enamel if you do find a short to ground.
    > >> --
    > >> If disconnecting the secondary from the bridge removes the short,
    > >> then try disconnecting the output supply that goes from the bridge and
    > >> caps into the amp.

    >
    > >> Also, you may have a time delayed on or soft start circuit that may not
    > >> be soft starting.

    >
    > >> P.S.
    > >> Because a CAP or bridge test ok at DMM voltage levels does not mean
    > >> they are good.

    >
    > >> --
    > >> "I'm never wrong, once i thought i was, but was mistaken"
    > >> Real Programmers Do things like this.
    > >>http://webpages.charter.net/jamie_5

    >
    > > If you can lay hands on a variac, use that to power the unit. This kind of
    > > fault then becomes a breeze to locate (the basic cause of). If it turns
    > > out to be related to the output stages - and I'm not quite sure of what
    > > you are measuring to come up with your "800 ohms" figure - then how simple
    > > or not the *actual* problem is, is a whole new ball game with DC coupled
    > > amps like this ...

    >
    > > Arfa

    >
    > I'm going to assume the typical.
    >
    > 1. An amp channel is blown.
    > 2. The associated emitter resistor is not blown yet since the fuse blows.
    > 3. You can measure from the center leg of each emitter resistor to the
    > collector tabs of the associated output transistors.
    > 4. When you find a channel where the emitter is shorted to one or both
    > collectors, you've found your blown channel.
    > 5. There are often other parts bad as well, though the Yamaha amp channels
    > are pretty easy. Often there is a resistor between the driver transistors
    > which is burned - usually 220 ohms, and of course the drivers are suspect,
    > the bias transistor could be bad OR HAVE BAD SOLDER CONNECTIONS which caused
    > the failure in the first place, and there could be another resistor bad
    > which feeds the B+ or B- voltage to a driver - usually 47 ohms.
    >
    > Mark Z.- Hide quoted text -
    >
    > - Show quoted text -


    I do have a variac, I am not sure how it really helps finds the fault,
    though. I have not determined yet whether the short is in the power
    supply board or the output transistors.
    Thanks
     
    , Oct 10, 2007
    #6
  7. Guest

    Ok, one step closer. I replaced the two 10,000uf 71v power supply
    caps with two 12,000uf 80v caps I had and now the fuse does NOT blow
    when I push the power button. But, I hear a relay click and the unit
    does still not power up.
     
    , Oct 10, 2007
    #7
  8. Arfa Daily Guest

    <> wrote in message
    news:...
    > Ok, one step closer. I replaced the two 10,000uf 71v power supply
    > caps with two 12,000uf 80v caps I had and now the fuse does NOT blow
    > when I push the power button. But, I hear a relay click and the unit
    > does still not power up.
    >
    >


    It's hard to say exactly what that implies, other than that one of the two
    caps was short circuit. I have to say though, that it is rare for large
    electros like those to fail short circuit. Have you tried measuring them to
    see if either is short ? Is it the standby relay that is clicking, or is
    there a delay before you hear the relay, and it is the output relays that
    you are hearing ? If the standby relay, does it drop straight back out ?
    This is what commonly happens on Yammies when there is an output fault. If
    it looks like there is an output fault, go with the good checking advice
    that Mark gave. He does a lot of these AV amps, and is well worth following
    for specific advice on them.

    Arfa
     
    Arfa Daily, Oct 10, 2007
    #8
  9. Guest

    On Oct 10, 8:56 am, "Arfa Daily" <> wrote:
    > <> wrote in message
    >
    > news:...
    >
    > > Ok, one step closer. I replaced the two 10,000uf 71v power supply
    > > caps with two 12,000uf 80v caps I had and now the fuse does NOT blow
    > > when I push the power button. But, I hear a relay click and the unit
    > > does still not power up.

    >
    > It's hard to say exactly what that implies, other than that one of the two
    > caps was short circuit. I have to say though, that it is rare for large
    > electros like those to fail short circuit. Have you tried measuring them to
    > see if either is short ? Is it the standby relay that is clicking, or is
    > there a delay before you hear the relay, and it is the output relays that
    > you are hearing ? If the standby relay, does it drop straight back out ?
    > This is what commonly happens on Yammies when there is an output fault. If
    > it looks like there is an output fault, go with the good checking advice
    > that Mark gave. He does a lot of these AV amps, and is well worth following
    > for specific advice on them.
    >
    > Arfa


    I believe it is the standby relay which is located on the circuit
    board right at the ac mains input. I believe my next step is to find
    the output transistor fault.
     
    , Oct 10, 2007
    #9
  10. PeterD Guest

    On Wed, 10 Oct 2007 15:56:27 GMT, "Arfa Daily"
    <> wrote:

    >
    ><> wrote in message
    >news:...
    >> Ok, one step closer. I replaced the two 10,000uf 71v power supply
    >> caps with two 12,000uf 80v caps I had and now the fuse does NOT blow
    >> when I push the power button. But, I hear a relay click and the unit
    >> does still not power up.
    >>
    >>

    >
    >It's hard to say exactly what that implies, other than that one of the two
    >caps was short circuit. I have to say though, that it is rare for large
    >electros like those to fail short circuit. Have you tried measuring them to
    >see if either is short ? Is it the standby relay that is clicking, or is
    >there a delay before you hear the relay, and it is the output relays that
    >you are hearing ? If the standby relay, does it drop straight back out ?
    >This is what commonly happens on Yammies when there is an output fault. If
    >it looks like there is an output fault, go with the good checking advice
    >that Mark gave. He does a lot of these AV amps, and is well worth following
    >for specific advice on them.
    >
    >Arfa
    >


    The OP may want to check the diodes in the bridge, one (or more?) may
    have blown with the bad caps, and the PS now is not delivering enough
    voltage to power (up) the unit.
     
    PeterD, Oct 10, 2007
    #10
  11. <> wrote in message
    news:...
    > Ok, one step closer. I replaced the two 10,000uf 71v power supply
    > caps with two 12,000uf 80v caps I had and now the fuse does NOT blow
    > when I push the power button. But, I hear a relay click and the unit
    > does still not power up.
    >
    >


    Sounds like the emitter resistor has now failed, so the fuse no longer
    blows...

    Mark Z.
     
    Mark D. Zacharias, Oct 11, 2007
    #11
  12. "Mark D. Zacharias" <> wrote in message
    news:xWdPi.1447$...
    >
    > <> wrote in message
    > news:...
    >> Ok, one step closer. I replaced the two 10,000uf 71v power supply
    >> caps with two 12,000uf 80v caps I had and now the fuse does NOT blow
    >> when I push the power button. But, I hear a relay click and the unit
    >> does still not power up.
    >>
    >>

    >
    > Sounds like the emitter resistor has now failed, so the fuse no longer
    > blows...
    >
    > Mark Z.
    >

    Of course, you could have a shorted filter cap, but this would be pretty
    unusual on a newer unit.

    mz
     
    Mark D. Zacharias, Oct 11, 2007
    #12
  13. James Sweet Guest


    > If you can lay hands on a variac, use that to power the unit. This kind of
    > fault then becomes a breeze to locate (the basic cause of). If it turns
    > out to be related to the output stages - and I'm not quite sure of what
    > you are measuring to come up with your "800 ohms" figure - then how simple
    > or not the *actual* problem is, is a whole new ball game with DC coupled
    > amps like this ...
    >



    Use a large incandescent lightbulb wired in series with the unit for
    testing. It's cheaper than a variac and in this case is a better solution.
    200-300W should do it.
     
    James Sweet, Oct 11, 2007
    #13
  14. Guest

    On Oct 10, 10:32 pm, "James Sweet" <> wrote:
    > > If you can lay hands on a variac, use that to power the unit. This kind of
    > > fault then becomes a breeze to locate (the basic cause of). If it turns
    > > out to be related to the output stages - and I'm not quite sure of what
    > > you are measuring to come up with your "800 ohms" figure - then how simple
    > > or not the *actual* problem is, is a whole new ball game with DC coupled
    > > amps like this ...

    >
    > Use a large incandescent lightbulb wired in series with the unit for
    > testing. It's cheaper than a variac and in this case is a better solution.
    > 200-300W should do it.


    Ok, I dug a bit deeper and found that the two center channel power
    transistors were shorted. I replaced them with the rear channel
    devices to see if it would work.
    The fuse no longer blows but the standby relay still kicks it out.
    The difference is that the display comes on momentarily and no fuse
    blowing.
    So either I have more issues on the center channel or the protection
    circuitry knows that the rear channel transistors are missing.
     
    , Oct 15, 2007
    #14
  15. James Sweet Guest

    <> wrote in message
    news:...
    > On Oct 10, 10:32 pm, "James Sweet" <> wrote:
    >> > If you can lay hands on a variac, use that to power the unit. This kind
    >> > of
    >> > fault then becomes a breeze to locate (the basic cause of). If it turns
    >> > out to be related to the output stages - and I'm not quite sure of what
    >> > you are measuring to come up with your "800 ohms" figure - then how
    >> > simple
    >> > or not the *actual* problem is, is a whole new ball game with DC
    >> > coupled
    >> > amps like this ...

    >>
    >> Use a large incandescent lightbulb wired in series with the unit for
    >> testing. It's cheaper than a variac and in this case is a better
    >> solution.
    >> 200-300W should do it.

    >
    > Ok, I dug a bit deeper and found that the two center channel power
    > transistors were shorted. I replaced them with the rear channel
    > devices to see if it would work.
    > The fuse no longer blows but the standby relay still kicks it out.
    > The difference is that the display comes on momentarily and no fuse
    > blowing.
    > So either I have more issues on the center channel or the protection
    > circuitry knows that the rear channel transistors are missing.
    >



    There's a good chance the latter is the case.
     
    James Sweet, Oct 15, 2007
    #15
  16. Arfa Daily Guest

    "James Sweet" <> wrote in message
    news:VXNQi.979$GM2.581@trndny02...
    >
    > <> wrote in message
    > news:...
    >> On Oct 10, 10:32 pm, "James Sweet" <> wrote:
    >>> > If you can lay hands on a variac, use that to power the unit. This
    >>> > kind of
    >>> > fault then becomes a breeze to locate (the basic cause of). If it
    >>> > turns
    >>> > out to be related to the output stages - and I'm not quite sure of
    >>> > what
    >>> > you are measuring to come up with your "800 ohms" figure - then how
    >>> > simple
    >>> > or not the *actual* problem is, is a whole new ball game with DC
    >>> > coupled
    >>> > amps like this ...
    >>>
    >>> Use a large incandescent lightbulb wired in series with the unit for
    >>> testing. It's cheaper than a variac and in this case is a better
    >>> solution.
    >>> 200-300W should do it.

    >>
    >> Ok, I dug a bit deeper and found that the two center channel power
    >> transistors were shorted. I replaced them with the rear channel
    >> devices to see if it would work.
    >> The fuse no longer blows but the standby relay still kicks it out.
    >> The difference is that the display comes on momentarily and no fuse
    >> blowing.
    >> So either I have more issues on the center channel or the protection
    >> circuitry knows that the rear channel transistors are missing.
    >>

    >
    >
    > There's a good chance the latter is the case.
    >

    Agreed. This is common for Yammies, and is a most frustrating characteristic
    when you want to just check that all the other channels work before putting
    in a firm quote. I have one sitting up the corner of the workshop waiting
    for transistors right now, that does exactly as you describe, with the bad
    ones removed. You will be quite lucky if there are no issues other than bad
    output transistors on your originally faulty channel.

    Arfa
     
    Arfa Daily, Oct 16, 2007
    #16
  17. Guest

    On Oct 15, 4:57 pm, "Arfa Daily" <> wrote:
    > "James Sweet" <> wrote in message
    >
    > news:VXNQi.979$GM2.581@trndny02...
    >
    >
    >
    >
    >
    > > <> wrote in message
    > >news:...
    > >> On Oct 10, 10:32 pm, "James Sweet" <> wrote:
    > >>> > If you can lay hands on a variac, use that to power the unit. This
    > >>> > kind of
    > >>> > fault then becomes a breeze to locate (the basic cause of). If it
    > >>> > turns
    > >>> > out to be related to the output stages - and I'm not quite sure of
    > >>> > what
    > >>> > you are measuring to come up with your "800 ohms" figure - then how
    > >>> > simple
    > >>> > or not the *actual* problem is, is a whole new ball game with DC
    > >>> > coupled
    > >>> > amps like this ...

    >
    > >>> Use a large incandescent lightbulb wired in series with the unit for
    > >>> testing. It's cheaper than a variac and in this case is a better
    > >>> solution.
    > >>> 200-300W should do it.

    >
    > >> Ok, I dug a bit deeper and found that the two center channel power
    > >> transistors were shorted. I replaced them with the rear channel
    > >> devices to see if it would work.
    > >> The fuse no longer blows but the standby relay still kicks it out.
    > >> The difference is that the display comes on momentarily and no fuse
    > >> blowing.
    > >> So either I have more issues on the center channel or the protection
    > >> circuitry knows that the rear channel transistors are missing.

    >
    > > There's a good chance the latter is the case.

    >
    > Agreed. This is common for Yammies, and is a most frustrating characteristic
    > when you want to just check that all the other channels work before putting
    > in a firm quote. I have one sitting up the corner of the workshop waiting
    > for transistors right now, that does exactly as you describe, with the bad
    > ones removed. You will be quite lucky if there are no issues other than bad
    > output transistors on your originally faulty channel.
    >
    > Arfa- Hide quoted text -
    >
    > - Show quoted text -


    I got it back together tonight. I used the presence transistors and
    placed them in the surround channel locations. I substituted an
    mjl1302a for the 2sa1492 and a mjl3281a for the 2sc3856.
    The case size for the mjl is larger than the original so I figured
    they would be ok in the open air since they were not used.
    It worked fine for over an hour and then the two mjls burned up. I
    could not figure out how to get zone2/zone3 off the display so that is
    probably why they failed. I guess I will order the correct ones that
    fit and all should be fine.
     
    , Oct 16, 2007
    #17
  18. Guest

    On Oct 15, 4:57 pm, "Arfa Daily" <> wrote:
    > "James Sweet" <> wrote in message
    >
    > news:VXNQi.979$GM2.581@trndny02...
    >
    >
    >
    >
    >
    > > <> wrote in message
    > >news:...
    > >> On Oct 10, 10:32 pm, "James Sweet" <> wrote:
    > >>> > If you can lay hands on a variac, use that to power the unit. This
    > >>> > kind of
    > >>> > fault then becomes a breeze to locate (the basic cause of). If it
    > >>> > turns
    > >>> > out to be related to the output stages - and I'm not quite sure of
    > >>> > what
    > >>> > you are measuring to come up with your "800 ohms" figure - then how
    > >>> > simple
    > >>> > or not the *actual* problem is, is a whole new ball game with DC
    > >>> > coupled
    > >>> > amps like this ...

    >
    > >>> Use a large incandescent lightbulb wired in series with the unit for
    > >>> testing. It's cheaper than a variac and in this case is a better
    > >>> solution.
    > >>> 200-300W should do it.

    >
    > >> Ok, I dug a bit deeper and found that the two center channel power
    > >> transistors were shorted. I replaced them with the rear channel
    > >> devices to see if it would work.
    > >> The fuse no longer blows but the standby relay still kicks it out.
    > >> The difference is that the display comes on momentarily and no fuse
    > >> blowing.
    > >> So either I have more issues on the center channel or the protection
    > >> circuitry knows that the rear channel transistors are missing.

    >
    > > There's a good chance the latter is the case.

    >
    > Agreed. This is common for Yammies, and is a most frustrating characteristic
    > when you want to just check that all the other channels work before putting
    > in a firm quote. I have one sitting up the corner of the workshop waiting
    > for transistors right now, that does exactly as you describe, with the bad
    > ones removed. You will be quite lucky if there are no issues other than bad
    > output transistors on your originally faulty channel.
    >
    > Arfa- Hide quoted text -
    >
    > - Show quoted text -


    I disconnected the power to the zone2/zone3 board which I do not plan
    on using and now it is working fine again and powering on
     
    , Oct 16, 2007
    #18
    1. Advertising

Want to reply to this thread or ask your own question?

It takes just 2 minutes to sign up (and it's free!). Just click the sign up button to choose a username and then you can ask your own questions on the forum.
Similar Threads
  1. Mark
    Replies:
    5
    Views:
    1,037
  2. Spaguetty

    TROUBLE YAMAHA HTR 5790

    Spaguetty, Oct 11, 2007, in forum: Electronic Repair
    Replies:
    1
    Views:
    514
    Mark D. Zacharias
    Oct 12, 2007
  3. Spaguetty

    NEED SCHEMATIC YAMAHA HTR 5790 OR 5890 "URGENT"

    Spaguetty, Oct 11, 2007, in forum: Electronic Repair
    Replies:
    0
    Views:
    558
    Spaguetty
    Oct 11, 2007
  4. bbutterfield

    Yamaha AV receiver HTR-5790 will not power up

    bbutterfield, Oct 26, 2009, in forum: Electronics Repair
    Replies:
    1
    Views:
    1,553
  5. Man-wai Chang

    Fuse: fast blown vs slow blown

    Man-wai Chang, May 31, 2011, in forum: Electronic Basics
    Replies:
    59
    Views:
    4,100
    Winston
    Jun 4, 2011
Loading...

Share This Page