68kMLA Classic Interface

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Dead Pismo
Posted by: Some_Person on 2022-01-17 13:11:27
I recently acquired a Pismo in excellent cosmetic condition, but it isn't working properly. When I first got it, it would chime, then the screen would briefly turn on, but then it would go out. Disconnecting the PRAM battery didn't change this, although I then discovered that if I removed the DVD drive, a horrible screeching noise would come from the machine while turned on (reinstalling the DVD drive would make the noise go away). I then tried reseating the RAM and CPU card, but now all that happens when I turn it on is that the fan whirs (no chime). Any ideas?
Posted by: joshc on 2022-01-17 23:55:47
I know you've probably checked it, but is the power adapter known good? Stable voltages? Have you got another you could try with?
Posted by: Some_Person on 2022-01-18 10:14:24
I know you've probably checked it, but is the power adapter known good? Stable voltages? Have you got another you could try with?
I actually haven't checked this. I only have one power adapter, an M4896, and no other machines I can test it with. Is there a straightforward way I can verify that it's working properly?
Posted by: 3lectr1cPPC on 2022-01-18 10:18:43
Check the voltages with a multimeter if you have one. If it’s outputting proper voltage it’s probably fine.
Posted by: Some_Person on 2022-01-18 17:52:04
Well... I think this thing is toast. I tried powering it up again, and although I got a chime and briefly a flickering screen, I also saw smoke come out of the modem port... sigh.
Posted by: 3lectr1cPPC on 2022-01-18 18:45:12
I'd take it apart and see what blew, who knows, maybe it's something repairable. If not, then at least you know where the fault is and you could replace whatever part went bad in the future to get a working machine. I still think you should take a voltage reading from the charger if you can, just to verify it isn't giving the Pismo too much voltage or anything (which could obviously blow something out).
Posted by: Some_Person on 2022-01-19 13:26:36
Think I've identified the problem. On the logic board, there's an inductor hanging in the air and a mosfet that also appears to be damaged.
Posted by: Some_Person on 2022-02-14 14:10:39
I bought a replacement logic board for this machine, but I am still having problems. The machine chimes, but the screen only briefly turns on before going dark. An external monitor behaves the same way. Any ideas?
Posted by: Johnnya101 on 2022-02-14 14:20:33
Did you ever test the power adapter?

Whatever is wrong seems like it kills the logic board.
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