8600 not booting

[weckart]

I recently acquired an 8600/250. It has approx 160MB of RAM, all the VRAM banks filled and external LaCie SCSI CDROM/JAZ/HDD units. The internal SCSI HDD was removed. Problem is, the unit does not boot. The power button glows green and the fans spin up but nothing more happens.

I have tried reseating all of the RAM and the CPU card. Nothing looks corroded or blown. The logic board looks ok. I have tried resetting the CUDA and the logic board. The PRAM battery still hold a charge. I also tried disconnecting the SCSI and floppy cables inside to see if I could get the bare logic board to respond. Apart from being filthy inside, it is in pretty good nick. I still cannot get a chime out of this.

The previous owner assures me it booted and ran fine before he packaged it up and he had only opened it up to put in RAM in the past. I have cleaned it up as much as I can without totally disassembling the PSU but still cannot get a peep out of it. Is there anything I have missed?

 

[bunnspecial]

Bad RAM and/or oxidized RAM contacts can be a persistent source of problems in these computers.

As a starting point, I'd suggest removing all of the RAM in either "Bank A" or "Bank B" and then trying to boot. If you still don't get anywhere, take it down to a single stick of RAM and try booting. If you still get nowhere, move it around or try a different stick. If you can get it booting with one stick, you can then start adding the others back in one-by-one.

 

[weckart]

I did the RAM shuffle. I even tried booting without RAM to see if I would get an error beep and.. nothing. This leads me to think there must be something up with the CPU card or the logic board unless there is anything else I could try.

 

[bunnspecial]

Here's a stupid question that I hope you'll forgive me for asking, but is the speaker connected?

 

[weckart]

Here's a stupid question that I hope you'll forgive me for asking, but is the speaker connected?

Not stupid and I considered that there might have been an issue there. I checked and it looked intact from what I could see. All the cables to the logic board are ok and not frayed/bent/missing. I tried sticking in a VGA card from my B/W and the monitor does not detect any signal activity at all. Seems like no power or otherwise is getting to the PCI ports.

Running out of ideas but the logic board shouldn't die just like that. The only thing I can think of is that the CPU daughtercard was left in situ as it was in transit, which probably wasn't the smartest thing to do. The contacts look OK and there is perhaps a mm or two of play on either side for the daughterboard bank although it seems decently parked and did not work itself loose during shipping. I tried very gently rocking the board with the power on to see if it would spark some life into the unit but nada.

 

[bunnspecial]

You can always try the old stand-by of scrubbing the CPU card contacts with a pencil eraser followed by cleaning with denatured alcohol.

Then, insert and remove it from the slot 5 or 10 times.

 

[weckart]

Yup. Did that. The contacts looked pristine. I ran the 8600 for a quarter of an hour and the cpu got warm to the touch. Not sure if this means much but my hunch is something is up with the logic board. I even tried booting up without the daughter card and I got the same result. No beeps. No automatic switching off. Nothing that gives me any idea what is up. Pretty frustrating.

 

[bunnspecial]

Do you have any 604E cards you could try in it? That would at least(maybe) narrow it down to a CPU or logic board problem.

Also, do you have the L2 Cache DIMM? If so, you might try removing that.

Sorry if I'm tossing out stuff you've already tried-this is just the only way I know sometimes to troubleshoot OWR Macs. They're a ton of fun when they work, but can be nerve wracking when they don't.

 

[weckart]

Nope. Unfortunately this is the only OWR desktop I own, so am limited in spare parts. As far as I know, the cache slot was never used on the 8600. Mine is suitably empty. Keep throwing out ideas. It is often the barmiest that provides the key.