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730Re: Reviving my OSI C2OEM

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  • relayer
    Jun 17, 2005
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      I think I managed to short something out. There's no observable
      damage, but now I'm not getting any response or boot prompt on the

      I found my boot disks and was trying to get the thing running. The
      disk would just spin and spin after hitting "D" at the boot prompt and
      a boot disk in the drive. The head wouldn't even move from the first
      track (although the drive did seek to the starting track).

      I wanted to switch drives and noticed there were jumpers on the drive
      circuit board, at least on one of the drives. The other drive had wire
      wrapped jumpers from strange locations, so I couldn't really swap them
      yet. While I had the drives out to clean, etc., I saw after a time the
      terminal screen throwing out a continuous stream of garbage
      characters. I didn't realize I had it on. The C2 was off and
      unplugged, but the RS-232 connector was still hooked up to the C2. I
      turned off the terminal and finished up with the drives. I go to turn
      everything on and notice no terminal response, just the cursor. I hit
      the white button several times to no avail. Then I noticed that two
      boards 'may' have been touching. Apparently the last owner didn't
      believe in bolting down the ends of the boards. I probably shorted out
      the 505 board against the 535 board.

      I suppose troubleshooting is in order now. I'll need to break out my
      oscilloscope and find a service manual. Hopefully, I didn't blow out a
      rare component. I probably fried the U1A 6820 UART.
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