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Thread: Dead STV: some questions on components

  1. #1
    Paris-Dakar Rally Driver
    Dakar 2003

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    icon32.gif Dead STV: some questions on components

    Hi All,
    Between a pile of junk I recently obtained, I found a SEGA STV.

    Now, this board is probably junk for several reasons, but I don't like the idea of not at least trying to save it

    1) The board suffered water damage, it's not severe but it's all across the board. Probably left in the open for some time after it was tossed away for other issues. I cleaned it up with an ultrasonic bath. Came out well.
    2) The power led is dead. This screams overvoltage problem to me, which is probably what killed the board in the first place.
    3) When board is powered up, it presents a solid black screen. Test switch pressed at startup produces no result
    4) IC24, 25 and 27 get suspiciously hot when the board is turned on.
    5) Bus terminator is installed in the correct place
    6) Reflowed the two SH2 cpus, that did not change a thing.
    7) Checked the BIOS ic, and it's sane (verified that the MD5 matches a good dump).
    8) I can also see brief activity on the enable pin of said BIOS before the machine hangs (with all the data pins in high impedance state). So it's not totally dead.

    I was wondering about the ICs at position 24, 25 and 27: they're hot enough for me to avoid putting a finger on them for more than 5 seconds. They're marked with code HM524165CTT17S, can't find any info on them, beside the obvious thing that they're ram ICs: anyone knows something about them?
    Do they run hot on working boards?
    Anyone know their pin configuration?

    I'd like to search for replacements, but can't find much with that code.

  2. #2
    Tung's Hair Stylist
    segasonicfan's Avatar
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    4) IC24, 25 and 27 get suspiciously hot when the board is turned on.
    its time to make morning toast
    they're hot enough for me to avoid putting a finger on them for more than 5 seconds.
    and eggs
    trying to save it
    your efforts are valiant, but this sounds permafried. Power LED issue and heat indicates dead short on power rails and multiple blown ICs...
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  3. #3
    Paris-Dakar Rally Driver
    Dakar 2003

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    Yeah, I put the board in the pile named "for spares" a while ago. Also found too many corroded vias to be fixable. The short is not so evident though, a new led replacing the burnt one works fine. Probably this board was killed by over voltage.

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