(Topic ID: 40272)

Sega White Star sound problem

By Inkochnito

11 years ago


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  • 30 posts
  • 11 Pinsiders participating
  • Latest reply 4 years ago by nibre
  • Topic is favorited by 4 Pinsiders

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    #1 11 years ago

    I've got a problem with a Sega White Star board.
    The sound section doesn't work right.
    The volume plays at 100% at setting 1 and is off at setting 0.
    The sound is so loud it's ear defning and distorted.
    I've changed the TDA1543 and the LM833 with no result.
    Anything I should look at now?

    Peter
    www.inkochnito.nl

    #2 11 years ago

    Noboby knows more about this system?
    This should really be documented more in the pinwiki.

    #5 11 years ago

    Yes, the sound stays at 100% at 1 or 13 or whatever setting accept for 0 being off.

    I'll ask if the board came from another game.

    Thanks for your help.
    I'll let you know how it turns out.

    Peter

    2 weeks later
    #14 11 years ago

    I was talking about a Whitestar CPU/Sound I Board.
    The board came out of a Monopoly and was placed in a Starship Troopers.
    I know now that the upgrade was indeed only for Whitestar CPU/Sound II Boards.
    So this info did not apply to me.

    I just ordered a new 74LS74 for U25 and 2 new TDA2030A for U101 and U102.
    They are not that expencive, but I would hate to mess up the board.

    #16 11 years ago

    Great to see something good come out of this.

    2 weeks later
    #19 11 years ago
    Quoted from viperrwk:

    But Peter, did you solve your problem?
    I'm wondering given your symptoms and the symptoms of the bad emulation on the WSII boards that perhaps your problem is a bad BSMT2000? Or perhaps a bad sound RAM at U4.
    viperrwk

    The problem is not solved with the change of U25 and the U101 & U102.
    Can a bad sound ram cause this kind of a problem?

    #21 11 years ago

    What I would like to know are the various functions of the individual chips.
    From what I have learned so far:
    U25 - 74LS74 function: ?
    U26 - TDA1543 function: translating digital to analog sounds.
    U30 - LM833 function: pre amplifier
    U101 &U102 function: end stage amplifier
    That's it so far.
    There are more chips that regulate the sound, but I'm not sure which ones does what.
    U23 and U24 must do something with sound too, as it is the input for U25 and it looks like these are in series with each other.
    Maybe for playing 2 sounds simultainious?
    U19 is a PAL16L8 and I haven't got a clu as to what this one is doing.
    Now where is volume regulated?

    Peter

    1 week later
    -1
    #22 10 years ago

    Problem has not been solved.
    The machine (with the board) has been sold "as is".
    Too bad, I'll guess we'll never know.

    I did learn that a PAL are programmable logic chips.
    These are mentioned on the PinWiki site.
    The puzzle remains.

    7 months later
    #23 10 years ago

    I've got an e-mail from someone who talked to Stern about this problem.
    He said to change R110 (33K 1/2watt) and R106 (10K 1/4 watt).
    That should fix the 100% volume problem.

    I would like to hear if anyone has tried this fix and if it works or not.

    #25 10 years ago

    I've been reading this document http://thepaisleys.com/paisleypinball/monopoly/eliminate_backbox_hum_and_buzz.htm
    and it realy makes sence....
    If R110 or R106 are broken, it would turn up the volume to 100% without being able to regulate it digitaly.
    The lower the value for R110 and R106, the lower the analog volume.
    With the digital volume you can turn up the volume again, giving you more control.

    6 years later
    #28 4 years ago

    Just try it.
    It 5 cents of parts...

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