First post, by compgeke
First off, I'd like to thank oeuvre for linking me to this thing. Without him this would probably be heading to scrap already.
This is that Quad, wait, make that a Dual 486 box that was mentioned over in the ebay finds thread, original post here: Post 561732 .
I managed to grab it as the only bidder and picked it up a few days later. One thing I wasn't aware of was the sheer size of the thing, it's absolutely gigantic. Full dimensions are 29 inches tall, 32.5 inches deep and 7.75 inches wide. Total weight with the UPS is 110.9 pounds (I shit you not).
Getting it home in the back seat of a Toyota Avalon
So, the specs on this thing (when I got it):
Dual 486 with 2x 50 MHz 486 DX50s. That's right, DX50s.
Shoot, those are cache controllers not two more CPUs
What looks like 12x 4 MB RAM sticks. It has a total of 24 slots.
NCR 77C22 VGA Graphics onboard
Not sure what the 8088 does, but you can see the VGA controller above it
NCR Dual Channel SCSI Controller, not sure which model yet but it's based on the 53C700 chip
Buslogic BT-646S/D SCSI Controller, nothing hooked internally only being used for external SCSI. I stole this and threw it in my PS/2 P70.
no picture!
SMC 8013EP/A Ethernet Card. Stole this and threw it in my PS/2 P70 as it has native packet drivers. The P70's IBM LAN Adapter/A now resides in the NCR.
NCR MPCA/MCA Multiprotocol Communications Card
525 MB QIC Tape Drive
Toshiba XM-5301B 4x CD-ROM (dated '95, it's newer than the rest of the system).
Now, as to the problem with it. The ebay listing stated "Does not power on but in fair condition". They're not wrong, it won't turn on. If you try this is all you get: https://www.youtube.com/watch?v=79Un66hZxf4 . That's after removing a bad capacitor, before it did even less.
What's the deal with that? Why would it be doing that? Oh I dunno, only that the PSU has suffered a catastrophic failure. There's a choke that's been hot enough to burn the insulation off the wire, burn the paper beside it, delayer the bottom of the PCB and it arced over onto the casing. There's also a cap that was severely bloated, leaking and it apparently got hot enough to melt some wire insulation to it. Not good.
The observant will notice that's not the original fan. It wouldn't spin well, a video of that: https://www.youtube.com/watch?v=9uMxvRfavtU
As for what went wrong and fixing the PSU, I don't know. I can only hope the problem is that capacitor shorted (between 5V and ground as a filter cap) and it's what led to insane current draw through that choke and all the heat damage. The system itself doesn't have any noticeable ground faults or damage anywhere so I assume this is all localized to a PSU failure. The bad fan and cap probably didn't help anything. Unfortunately SMPS PSU repair is a bit above my ability but I'll try and see what I can do, I certainly don't want to break it more.
Anyway, here're some more pics of the system. For full res pictures see the imgur album here: http://imgur.com/a/0C2JM . Warning: Album has a lot of 1-2 MB+ pictures.
Yeah, I took this one with a different camera. Is it obvious?
All the SCSI devices connect via caddies into this backplane system. I'm very very very very thankful I got 4 HDD caddies plus the two external SCSI caddies and the floppy one with this.
There's a case closed switch and a "Use the UPS or no?" switch". The red\black unplugged cables with spade connectors are actually for the system clock\memory battery. It's a little 6V Lead Acid that goes there, http://i.imgur.com/FfIYQAP.jpg .