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Erratic power-on behaviour O2 - WillumpieNL - 02-20-2019

After years (decades even) of drooling over cool SGI (and other "exotic" Unix hardware) equipment I lately decided to go for it and buy an O2 for cheap. It included a 1600SW display and original keyboard so it was quite a good deal. The owner didn't know what kind of O2 it was, but it turned out to be a 400mhz R12K with 1GB of RAM so that was a nice bonus as well. Only problem is: it wouldnt boot. But I saw that as a nice challenge anyway, kind of naive.

But the probleem seems kind of hard to diagnose right now. The machine instantly powers on when I plug in the power cord. After that I either get:
- red LED
- solid amber LED
- blinking amber LED
- green LED, no start-up chime
- green LED, start-up chime, blank display (but DOES sync)

The further down the list you go, the less I have seen it. Mostly red and amber LED's. What I have tried:
- remove all RAM and insert various combinations of 2
- reseated AND cleaned all components
- replaced PSU

No luck so far. I have also raised my question at the Discord channel where some said it is most likely a malfunctioning mainboard. Seemed quite plausible to me so I started earching for a replacement but that is harder than I thought. I can't find anyone (local) that has a spare R10K mainboard. But now I'm starting to question myself: might it be something else?  :huh:

I have, of course, read the manual and the troubleshooting diagram, so I know what the LED codes mean. But the fact that the errors aren't constant it makes me wonder what it could be.


RE: Erratic power-on behaviour O2 - jan-jaap - 02-20-2019

Howdie,

Did you try to fire it up with keyboard & mouse detached and a serial null modem cable (9600/n/8/1) attached to see if it would put out some more info on the serial console?

If POST fails it should normally print the reason on the serial console.


RE: Erratic power-on behaviour O2 - WillumpieNL - 02-20-2019

No, I have not. Will it also print this out over serial terminal with red or solid amber LED? Because that's what I get most of the times.


RE: Erratic power-on behaviour O2 - jan-jaap - 02-21-2019

(02-20-2019, 10:58 PM)WillumpieNL Wrote:  No, I have not. Will it also print this out over serial terminal with red or solid amber LED? Because that's what I get most of the times.

Normally yes, but if the CPU is severely broken all bets are off. Normally you get something along the lines of "replace CPU" or "cache failure" "INT controller failed etc etc."

But a failed disk can can cause all sorts of SCSI problems and the system won't complete POST. Just hook up a PC with putty and a null modem cable, select 9600/n/8/1 and fire up the O2.

Where in NL are you? I've got a known-good spare O2 R5000 mainboard for testing, but I'm not putting my own O2 / O2+ at risk.

PS: I guess you're the one on marktplaats.nl looking for an O2 mainboard?


RE: Erratic power-on behaviour O2 - WillumpieNL - 02-21-2019

(02-21-2019, 12:05 AM)jan-jaap Wrote:  
(02-20-2019, 10:58 PM)WillumpieNL Wrote:  No, I have not. Will it also print this out over serial terminal with red or solid amber LED? Because that's what I get most of the times.

Normally yes, but if the CPU is severely broken all bets are off. Normally you get something along the lines of "replace CPU" or "cache failure" "INT controller failed etc etc."

But a failed disk can can cause all sorts of SCSI problems and the system won't complete POST. Just hook up a PC with putty and a null modem cable, select 9600/n/8/1 and fire up the O2.

Where in NL are you? I've got a known-good spare O2 R5000 mainboard for testing, but I'm not putting my own O2 / O2+ at risk.

PS: I guess you're the one on marktplaats.nl looking for an O2 mainboard?
Ah, OK I'll fix myself a null modem cable then! Thanks.

Yes, that's me...  Wink  I live in Nijkerk btw.


RE: Erratic power-on behaviour O2 - dexter1 - 02-23-2019

Welcome Willumpie Smile

Your wide range of error results from your experiments suggest a (partial) broken CPU or Mainboard. It could be some trivial problem like broken solder joints, but fixing those on the CPU module f.i. would be very hard without a BGA solder facility.

I concur with Jan-Jaap that the only true approach will be swapping parts until it work.