Projection tv picture went out

Discussion in 'Electronic Repair' started by Chris, Jan 14, 2010.

  1. Chris

    Chris Guest

    I have an Akai PT5598HD 55 inch rear projection CRT television (made by
    Samsung). The other day, the screen suddenly went blank. Everything else
    (channel, input, sound, etc.) works perfect. Any self diagnosis/repair
    suggestions would be greatly appreciated.

    Thanks,

    Chris
     
    Chris, Jan 14, 2010
    #1
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  2. Chris

    Chris Guest

    "Meat Plow" wrote in message news:...
    > On Wed, 13 Jan 2010 20:16:16 -0800, "Chris" <>wrote:
    >
    >>I have an Akai PT5598HD 55 inch rear projection CRT television (made by
    >>Samsung). The other day, the screen suddenly went blank. Everything else
    >>(channel, input, sound, etc.) works perfect. Any self diagnosis/repair
    >>suggestions would be greatly appreciated.
    >>
    >>Thanks,
    >>
    >>Chris

    >
    > Unless you have some experience in electronic repair my only
    > suggestion is to have a professional look at it.
    >
    > One thing I'd like to ask is does the on screen display still work for
    > things like channel indicator or volume?


    No. Totally blank just like the set is turned off. I looked at the picture
    tubes and there is no orange glow. I have done minor electronic repairs.
    Also, I do HVAC, so I am well experienced in electrical
    troubleshooting/repairs. If I can positively identify the source of the
    problem, I can most likely do the repair. I'm willing to give it a shot
    before I pay someone $75 only to tell me that the repairs will exceed the
    cost of the tv.
     
    Chris, Jan 14, 2010
    #2
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  3. Chris

    circuit Guest

    Good luck with this. Maybe there is a way to determine what equivalent model
    Samsung chassis it is? Can you take some pictures of the insides showing the
    boards?



    "Chris" <> wrote in message
    news:mUw3n.7127$...
    >I have an Akai PT5598HD 55 inch rear projection CRT television (made by
    >Samsung). The other day, the screen suddenly went blank. Everything else
    >(channel, input, sound, etc.) works perfect. Any self diagnosis/repair
    >suggestions would be greatly appreciated.
    >
    > Thanks,
    >
    > Chris
     
    circuit, Jan 14, 2010
    #3
  4. Chris

    Sylvia Else Guest

    Chris wrote:
    > I have an Akai PT5598HD 55 inch rear projection CRT television (made by
    > Samsung). The other day, the screen suddenly went blank. Everything else
    > (channel, input, sound, etc.) works perfect. Any self diagnosis/repair
    > suggestions would be greatly appreciated.
    >
    > Thanks,
    >
    > Chris


    Just be aware, if you're not already, that CRTs have some particular
    safety issues. One of which is that they can give you a nasty electric
    shock long after the set's been turned off.

    Sylvia.
     
    Sylvia Else, Jan 17, 2010
    #4
  5. Chris

    Chris Guest

    "Sylvia Else" <> wrote in message
    news:0031b231$0$28425$...
    > Chris wrote:
    >> I have an Akai PT5598HD 55 inch rear projection CRT television (made by
    >> Samsung). The other day, the screen suddenly went blank. Everything else
    >> (channel, input, sound, etc.) works perfect. Any self diagnosis/repair
    >> suggestions would be greatly appreciated.
    >>
    >> Thanks,
    >>
    >> Chris

    >
    > Just be aware, if you're not already, that CRTs have some particular
    > safety issues. One of which is that they can give you a nasty electric
    > shock long after the set's been turned off.
    >
    > Sylvia.


    Thanks! I AM aware of this. But to clarify things, I have read that such
    components remain energized long after the set has been turned off. Mine has
    been unplugged for a week now. How long after being unplugged is a
    reasonable amount of time to insure all the energy is dissipated? My work
    schedule has precluded me from doing any further diagnosis since the problem
    began (last Saturday). However, once I start looking at (energizing) it
    again, I need to know how long I should wait after I unplug it to start
    probing around.

    To the other posters, I haven't responded since I haven't done anything else
    yet. But you will be the first to know when I do.

    Chris
     
    Chris, Jan 18, 2010
    #5
  6. Chris

    Sylvia Else Guest

    Chris wrote:
    >
    > "Sylvia Else" <> wrote in message
    > news:0031b231$0$28425$...
    >> Chris wrote:
    >>> I have an Akai PT5598HD 55 inch rear projection CRT television (made
    >>> by Samsung). The other day, the screen suddenly went blank.
    >>> Everything else (channel, input, sound, etc.) works perfect. Any self
    >>> diagnosis/repair suggestions would be greatly appreciated.
    >>>
    >>> Thanks,
    >>>
    >>> Chris

    >>
    >> Just be aware, if you're not already, that CRTs have some particular
    >> safety issues. One of which is that they can give you a nasty electric
    >> shock long after the set's been turned off.
    >>
    >> Sylvia.

    >
    > Thanks! I AM aware of this. But to clarify things, I have read that such
    > components remain energized long after the set has been turned off. Mine
    > has been unplugged for a week now. How long after being unplugged is a
    > reasonable amount of time to insure all the energy is dissipated?


    Some of the material I've read indicates that charge gets embedded (for
    the want of a better word) into the glass, and leaks out over a period
    that can extend into months. So you can't assume that leaving it
    unplugged for a week solves the problem. If you're going near the tube,
    you need to discharge it, and you need to be aware that if you leave it
    for a while (a vague expression meaning I don't know how long), then you
    need to discharge it again.

    Descriptions of the extent of the problem range from "not really a
    problem at all" to "it can kill you". I don't know how to judge between
    them.

    Search Google for discharge +CRT

    Sylvia.
     
    Sylvia Else, Jan 18, 2010
    #6
  7. Chris

    Sylvia Else Guest

    wrote:
    > On Jan 18, 1:27 pm, "Chris" <> wrote:
    >> "Sylvia Else" <> wrote in message
    >>
    >> news:0031b231$0$28425$...
    >>
    >>> Chris wrote:
    >>>> I have an Akai PT5598HD 55 inch rear projection CRT television (made by
    >>>> Samsung). The other day, the screen suddenly went blank. Everything else
    >>>> (channel, input, sound, etc.) works perfect. Any self diagnosis/repair
    >>>> suggestions would be greatly appreciated.
    >>>> Thanks,
    >>>> Chris
    >>> Just be aware, if you're not already, that CRTs have some particular
    >>> safety issues. One of which is that they can give you a nasty electric
    >>> shock long after the set's been turned off.
    >>> Sylvia.

    >> Thanks! I AM aware of this. But to clarify things, I have read that such
    >> components remain energized long after the set has been turned off. Mine has
    >> been unplugged for a week now. How long after being unplugged is a
    >> reasonable amount of time to insure all the energy is dissipated? My work
    >> schedule has precluded me from doing any further diagnosis since the problem
    >> began (last Saturday). However, once I start looking at (energizing) it
    >> again, I need to know how long I should wait after I unplug it to start
    >> probing around.
    >>
    >> To the other posters, I haven't responded since I haven't done anything else
    >> yet. But you will be the first to know when I do.
    >>
    >> Chris

    >
    > Hard to believe a charge would still be there after a week but if is
    > was and you managed to discharge it through you, you'd be annoyed and
    > not dead. It's like touching a spark plug. Oh, you haven't done that
    > either? Of course you _could_ use a clip lead and screwdriver to
    > discharge it painlessly.


    While wearing protective eyewear, of course, incase you manage to
    implode the tube.

    Sylvia.
     
    Sylvia Else, Jan 18, 2010
    #7
  8. Chris

    Sofa Slug Guest

    Sylvia Else wrote:
    > Chris wrote:
    >>
    >> "Sylvia Else" <> wrote in message
    >> news:0031b231$0$28425$...
    >>> Chris wrote:
    >>>> I have an Akai PT5598HD 55 inch rear projection CRT television (made
    >>>> by Samsung). The other day, the screen suddenly went blank.
    >>>> Everything else (channel, input, sound, etc.) works perfect. Any
    >>>> self diagnosis/repair suggestions would be greatly appreciated.
    >>>>
    >>>> Thanks,
    >>>>
    >>>> Chris
    >>>
    >>> Just be aware, if you're not already, that CRTs have some particular
    >>> safety issues. One of which is that they can give you a nasty
    >>> electric shock long after the set's been turned off.
    >>>
    >>> Sylvia.

    >>
    >> Thanks! I AM aware of this. But to clarify things, I have read that
    >> such components remain energized long after the set has been turned
    >> off. Mine has been unplugged for a week now. How long after being
    >> unplugged is a reasonable amount of time to insure all the energy is
    >> dissipated?

    >
    > Some of the material I've read indicates that charge gets embedded (for
    > the want of a better word) into the glass, and leaks out over a period
    > that can extend into months. So you can't assume that leaving it
    > unplugged for a week solves the problem. If you're going near the tube,
    > you need to discharge it, and you need to be aware that if you leave it
    > for a while (a vague expression meaning I don't know how long), then you
    > need to discharge it again.
    >
    > Descriptions of the extent of the problem range from "not really a
    > problem at all" to "it can kill you". I don't know how to judge between
    > them.
    >
    > Search Google for discharge +CRT


    How to discharge your CRT without damaging it or getting shocked:

    First, disconnect the TV from AC power!...

    Using a long wire clip lead, connect one end of a long lead 10k (2 watts
    or more) resistor to the CRT ground (usually there is a metal band
    around the CRT - use that or a connecting metal bracket as a ground - DO
    NOT use the PCB chassis ground). You will be using the other end of the
    resistor to discharge the CRT. A safe, easy way to accomplish this is to
    securely tape the resistor to the long end of a plastic coat hanger with
    masking or electrical tape, and use the other end of the hanger as a
    handle.

    With one hand, use a 12" plastic ruler to carefully pry up the edge of
    the high voltage "suction cup" on the CRT. Using your other hand, touch
    the end of the resistor on the hanger to the anode contacts under the
    cup. You will see a spark and hear a 'pop' when it discharges
    (alternately, you could just slide the resistor under the cup until it
    touches the contacts, but be careful not to scratch the conductive
    coating on the CRT). Hold the resistor against the contacts for a few
    seconds. Remove it and move the clip lead up to the other end of the
    resistor. Now, touch the end of the resistor to the contacts again so
    that you are directly shorting the CRT to ground.

    It's now safe to remove the anode cup from the CRT. While wearing safety
    glasses, you can use a screwdriver to carefully depress one of the
    contacts under the cup and then remove it, but be very careful not to
    scratch the conductive coating or damage the CRT when you do this. After
    you have removed the cup, short the exposed contact on the CRT to ground
    again just to be on the safe side. You will probably see a much smaller
    spark, if any.

    When you are ready to reconnect the CRT cable, short the contact on the
    CRT to ground once more first. The CRT may have recovered enough charge
    to zap you, so you want to short it out again just before you replace
    the cup.
     
    Sofa Slug, Jan 19, 2010
    #8
  9. Chris

    Chris Guest

    <> wrote in message
    news:...
    On Jan 18, 1:27 pm, "Chris" <> wrote:
    > "Sylvia Else" <> wrote in message
    >
    > news:0031b231$0$28425$...
    >
    > > Chris wrote:
    > >> I have an Akai PT5598HD 55 inch rear projection CRT television (made by
    > >> Samsung). The other day, the screen suddenly went blank. Everything
    > >> else
    > >> (channel, input, sound, etc.) works perfect. Any self diagnosis/repair
    > >> suggestions would be greatly appreciated.

    >
    > >> Thanks,

    >
    > >> Chris

    >
    > > Just be aware, if you're not already, that CRTs have some particular
    > > safety issues. One of which is that they can give you a nasty electric
    > > shock long after the set's been turned off.

    >
    > > Sylvia.

    >
    > Thanks! I AM aware of this. But to clarify things, I have read that such
    > components remain energized long after the set has been turned off. Mine
    > has
    > been unplugged for a week now. How long after being unplugged is a
    > reasonable amount of time to insure all the energy is dissipated? My work
    > schedule has precluded me from doing any further diagnosis since the
    > problem
    > began (last Saturday). However, once I start looking at (energizing) it
    > again, I need to know how long I should wait after I unplug it to start
    > probing around.
    >
    > To the other posters, I haven't responded since I haven't done anything
    > else
    > yet. But you will be the first to know when I do.
    >
    > Chris


    Hard to believe a charge would still be there after a week but if is
    was and you managed to discharge it through you, you'd be annoyed and
    not dead.

    ***************
    I found this: "The CRT attached to the flyback has an inherent capacitance
    which can hold a high voltage charge for up to a week or more after the
    power is switched off." http://en.wikipedia.org/wiki/Flyback_transformer

    **************

    It's like touching a spark plug. Oh, you haven't done that
    either? Of course you _could_ use a clip lead and screwdriver to
    discharge it painlessly. I look at your problem as a fantastic
    opportunity to get that NEW TV you've been looking at.



    ************
    I have considered a new tv, but since this one is not that old, and
    considering the cost of new, I prefer to repair it. Anyway, all three (red,
    blue, green) CRTs went out simultaneously. That tells me that it is probably
    something other than the CRTs; perhaps the flyback. What do you think?
     
    Chris, Jan 22, 2010
    #9
  10. Chris

    Chris Guest

    "Meat Plow" wrote in message news:...
    > On Thu, 14 Jan 2010 08:55:49 -0800, "Chris" <>wrote:
    >
    >>
    >>"Meat Plow" wrote in message news:...
    >>> On Wed, 13 Jan 2010 20:16:16 -0800, "Chris" <>wrote:
    >>>
    >>>>I have an Akai PT5598HD 55 inch rear projection CRT television (made by
    >>>>Samsung). The other day, the screen suddenly went blank. Everything else
    >>>>(channel, input, sound, etc.) works perfect. Any self diagnosis/repair
    >>>>suggestions would be greatly appreciated.
    >>>>
    >>>>Thanks,
    >>>>
    >>>>Chris
    >>>
    >>> Unless you have some experience in electronic repair my only
    >>> suggestion is to have a professional look at it.
    >>>
    >>> One thing I'd like to ask is does the on screen display still work for
    >>> things like channel indicator or volume?

    >>
    >>No. Totally blank just like the set is turned off. I looked at the picture
    >>tubes and there is no orange glow. I have done minor electronic repairs.
    >>Also, I do HVAC, so I am well experienced in electrical
    >>troubleshooting/repairs. If I can positively identify the source of the
    >>problem, I can most likely do the repair. I'm willing to give it a shot
    >>before I pay someone $75 only to tell me that the repairs will exceed the
    >>cost of the tv.

    >
    > Since you can obviously use a voltmeter you need to start with a print
    > of the power supply and voltage chart at certain test points. You
    > might plug the model number of the set into Google.com and see if
    > there are others who experienced the same/similar failure. Google also
    > might help to secure a schematic. I know by reading some Samsung
    > chassis had common faults for convergence processing components and
    > CRT leaks.
    >
    > You also might want to pull the chassis out and give it a good visual
    > in plenty of light, maybe something will show up. Visual inspection
    > was always my first step and often can narrow down your trouble
    > shooting steps. Heck it could be something as simple as an onboard
    > fuse or fusable link and those can be checked with minimal effort.
    >
    > Also certain models had built in error codes that made the power
    > indicator blink in certain patterns depending on thefault. Check into
    > that. Also check that the AC cord is supplying the set. I've seen
    > simple failures like this many times.


    Well, I finally broke down and sprung the 80 bucks, and had a tech come over
    this morning. He said the deflection board has to be replaced. He explained
    how relatively easy it was to do, and that with my experience, it should be
    no problem. Not to mention, will be significantly cheaper doing it myself.
    He also turned me on to a couple web sites that their own company uses for
    parts. I will have to wait until Monday to contact them since I am having
    limited luck finding the part online. In case anyone has a desire to help me
    locate it, the model info is at the beginning of this post. I have
    additional numbers if need be.

    Thanks
     
    Chris, Jan 24, 2010
    #10
  11. Chris

    Chris Guest

    May not need to take photos, but will if necessary. I know what the problem
    is as indicated in my other post today. I will try to locate the part
    Monday. But if I hit dead ends, I can post a photo.

    "circuit" <> wrote in message
    news:hio7tp$dp4$...
    > Good luck with this. Maybe there is a way to determine what equivalent
    > model
    > Samsung chassis it is? Can you take some pictures of the insides showing
    > the
    > boards?
    >
    >
    >
    > "Chris" <> wrote in message
    > news:mUw3n.7127$...
    >>I have an Akai PT5598HD 55 inch rear projection CRT television (made by
    >>Samsung). The other day, the screen suddenly went blank. Everything else
    >>(channel, input, sound, etc.) works perfect. Any self diagnosis/repair
    >>suggestions would be greatly appreciated.
    >>
    >> Thanks,
    >>
    >> Chris

    >
     
    Chris, Jan 24, 2010
    #11
  12. Chris

    Chris Guest

    "Sansui Samari" <> wrote in message
    news:...
    On Jan 18, 5:47 pm, Sofa Slug <> wrote:
    > Sylvia Else wrote:
    > > Chris wrote:

    >
    > >> "Sylvia Else" <> wrote in message
    > >>news:0031b231$0$28425$...
    > >>> Chris wrote:
    > >>>> I have an Akai PT5598HD 55 inch rear projection CRT television (made
    > >>>> by Samsung). The other day, the screen suddenly went blank.
    > >>>> Everything else (channel, input, sound, etc.) works perfect. Any
    > >>>> self diagnosis/repair suggestions would be greatly appreciated.

    >
    > >>>> Thanks,

    >
    > >>>> Chris

    >
    > >>> Just be aware, if you're not already, that CRTs have some particular
    > >>> safety issues. One of which is that they can give you a nasty
    > >>> electric shock long after the set's been turned off.

    >
    > >>> Sylvia.

    >
    > >> Thanks! I AM aware of this. But to clarify things, I have read that
    > >> such components remain energized long after the set has been turned
    > >> off. Mine has been unplugged for a week now. How long after being
    > >> unplugged is a reasonable amount of time to insure all the energy is
    > >> dissipated?

    >
    > > Some of the material I've read indicates that charge gets embedded (for
    > > the want of a better word) into the glass, and leaks out over a period
    > > that can extend into months. So you can't assume that leaving it
    > > unplugged for a week solves the problem. If you're going near the tube,
    > > you need to discharge it, and you need to be aware that if you leave it
    > > for a while (a vague expression meaning I don't know how long), then you
    > > need to discharge it again.

    >
    > > Descriptions of the extent of the problem range from "not really a
    > > problem at all" to "it can kill you". I don't know how to judge between
    > > them.

    >
    > > Search Google for discharge +CRT

    >
    > How to discharge your CRT without damaging it or getting shocked:
    >
    > First, disconnect the TV from AC power!...
    >
    > Using a long wire clip lead, connect one end of a long lead 10k (2 watts
    > or more) resistor to the CRT ground (usually there is a metal band
    > around the CRT - use that or a connecting metal bracket as a ground - DO
    > NOT use the PCB chassis ground). You will be using the other end of the
    > resistor to discharge the CRT. A safe, easy way to accomplish this is to
    > securely tape the resistor to the long end of a plastic coat hanger with
    > masking or electrical tape, and use the other end of the hanger as a
    > handle.
    >
    > With one hand, use a 12" plastic ruler to carefully pry up the edge of
    > the high voltage "suction cup" on the CRT. Using your other hand, touch
    > the end of the resistor on the hanger to the anode contacts under the
    > cup. You will see a spark and hear a 'pop' when it discharges
    > (alternately, you could just slide the resistor under the cup until it
    > touches the contacts, but be careful not to scratch the conductive
    > coating on the CRT). Hold the resistor against the contacts for a few
    > seconds. Remove it and move the clip lead up to the other end of the
    > resistor. Now, touch the end of the resistor to the contacts again so
    > that you are directly shorting the CRT to ground.
    >
    > It's now safe to remove the anode cup from the CRT. While wearing safety
    > glasses, you can use a screwdriver to carefully depress one of the
    > contacts under the cup and then remove it, but be very careful not to
    > scratch the conductive coating or damage the CRT when you do this. After
    > you have removed the cup, short the exposed contact on the CRT to ground
    > again just to be on the safe side. You will probably see a much smaller
    > spark, if any.
    >
    > When you are ready to reconnect the CRT cable, short the contact on the
    > CRT to ground once more first. The CRT may have recovered enough charge
    > to zap you, so you want to short it out again just before you replace
    > the cup.


    I'm glad to see someone explaining this in english. I started working
    on televisions eons ago, before the internet, as a kid, and it took
    me forever to figure out how to ground out the crt without killing it,
    me, or other circuitry.

    **************

    I finally located the "no longer available" deflection board for my tv.
    Ordered it today. Will post the results when I get it replaced.
     
    Chris, Jan 27, 2010
    #12
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