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Plasma service manuals, no PS or syscon schematics?

Discussion in 'Electronic Repair' started by jango2, Jun 14, 2007.

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  1. jango2

    jango2 Guest

    Hi folks,
    How come plasma service manuals come without a power supply and syscon
    schematic ? I paid 25 US$ and i'm told manufacturers never publish PS
    schematics in the service manual. Incidentally the TV i'm trying to
    fix is a Hitachi 42PD7800TA Plasma display panel. The ps is made by
    Murata MPF7415. The Murata website offers no info on the ps either. I
    guess thats understandable ...OEM.
    Symptom: Set clicks on (relay sound) some supplies are available, 30
    volts measured at 35, Vs and Va are both very low ( 5 volts instead of
    63) and then the set clicks off (protect?)
    The power control pin of the ps seems to recognise 0.05 volts as an on
    signal. If i disconnect that then the set wont turn on at all. The set
    trips within 2 seconds from power on. Any clues? The manual i've got
    is 16 Mb. Does anyone here have the full manual? How big is it? Even
    the syscon section is missing from the manual.
  2. The manufacturers don't want you to repair the boards. They want you to
    buy a replacement board at a ridiculous price or replace the whole TV.
    The service manual should be enough to help you determine which board is
    defective and then it's up to you to find a replacement, and hope that
    the plasma panel is not loading down the PS and blow it again.
  3. ....Also, if you know which board is defective you can often find and
    replace the defective components - if they are available.
    I've seen custom hybrid power modules that are not available to anyone
    but the board manfacturer in some sets.
  4. Guest

    As a last resort you can try to email the manufacturer of the ps
    unit and ask them for the schematics, some out there will willingly
    supply the information, I have done that with a bestec supply a few
    years ago, first of all they sent it in taiwanese but after another
    email asking for it in english they sent that 1 to me too.
    Good luck.
  5. jango2

    jango2 Guest

    Damn X and Y sus schematics are missing too. I got 4 shorted IGBTs so
    far GT30G131. I refuse to let this deter me. I'm a chip level repair
    technician and i will NOT be made redundant. screw you Hitachi.
  6. jango2

    jango2 Guest

    I forgot to state the shorted IGBTs are on the Ysus board, PS seems ok
    when i disconnect vs and va from load (xsus ,ysus)
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