Resurrecting an Advantech PCA-6157

Stinkerton18

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Aug 18, 2022
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For those who aren't familiar with the Advantech PCA-6157, it's a Socket 7 Single Board computer with 4 72-pin SIMM slots, no onboard video, ISA and PCI backplane compatibility. I don't remember the exact spec name but it's pretty common/standard with the 16-bit ISA connectors first, followed by the PCI ones inline. I picked it up at our local e-waste facility as an unknown. It was missing RAM, CPU, the BIOS EEPROM (??), and the AMIKEY-2 keyboard controller (?!?!??). Why both the EEPROM and the keyboard controller? I don't know, just guessing someone nabbed them as spares for a different project of theirs. I figured a replacement EEPROM, keyboard controller, and it should be good to go.

I managed to get the BIOS file directly from Advantech (their customer support is amazing for even responding to my inquiry and providing the file), attached if anyone else is interested. Yes I did also send it to TheRetroWeb as they didn't have it yet. Flashed this onto an SST39SF010A chip, verirfied the flash took and the chip contents matched those of the bin file, popped said chip into the BIOS socket on the SBC, transferred a Pentium 120Mhz CPU and RAM from a working socket 7 board, plugged the SBC into a known good backplane, hit the switch and.....nothing.

POST card, in either an ISA or PCI slot, shows nothing either, just - across all four segmented LED displays. The backplane does have LEDs for the different rails and other than -5v (ATX PSU), the rest are present. I don't have a replacement keyboard controller in yet, that socket is still empty. There is a single Diagnostic LED on the SBC itself that did light up, CPU gets a tad warm but nothing else is really getting warm or "hot burny shorty shorty".

Correct me if I'm wrong but...can the lack of a keyboard controller actually prevent an x86 PC from even POSTing? I would expect the board to complete the POST, then err cause "no keyboard".
 

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jdmcs

TinkerDifferent Board DoP&G
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Oct 28, 2021
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Central Virginia
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Most x86 computers will start to POST with a missing keyboard controller; however, I would expect that it will hang fairly early. The keyboard controller usually controls the A20 gate, and that’s usually a fatal error when the BIOS is unable to control it (as that prevents proper access to memory above 1MB).