Onyx2 Deskside no longer sees any internal SCSI devices

[mgchristensen]

This one has me completely stumped. Previously working Onyx2 Deskside, on startup, no longer finds any internal SCSI devices on startup. I have swapped the IO6G with a second 100% functional Onyx2 (machine #2), still no drives found in machine #1, and the swapped IO6G works in machine #2. The system drive from #1 boots in #2, all other hard drives appear on startup in #2 and noe found in machine #1.

I am using a serial terminal to watch the boot process, and can see when the two SCSI buses are walked on both machines. I have not tried yet attaching a terminal to the diagnostic port and turning the key switch to the diagnostic position.

I cannot find any info specific to the Onyx2 midplane, but the Origin ™ and Onyx2™ Theory of Operations Manual (Document Number 007-3439-002) on pages 65 and 66 shows a picture of the Origen2000 midplane, which I am assuming is similar. It appears that the internal SCSI bus, including the far end termination, is contained entirely on the midplane. Diagram on page 70 shows that the internal SCSI bus on the front of the midplane connects to the IO6G SCSI controller via the white square connector at the top of the IO6G.

Schematics would be helpful, but I am sure such info has been lost to the mists of time, as SGI went through its changes and died.

Perhaps it is something so simple but so painful as broken connections on the midplane?

Any thoughts and feedback will be greatly appreciated. I can post any pictures or terminal output anyone might deem helpful.

Thanks!

 

[mgchristensen]

Additional info: I have been following the "resetenv" procedure found at wiki.preterhuman.net/Onyx2_diagnostics.

 

[Elf]

I basically agree with the speculation about the midplane; I wish I could say something more helpful but it's definitely one of those things that would have to be in front of you to examine

It might be worth trying some basics like contact cleaner, looking for broken or bent pins, and so on. Past that, not that I would suggest going out and getting one, but it might be one of those things where a SCSI analyzer would be very handy to look at things from both an electrical and protocol angle.