Maybe C6, C7 and C10 are for similar function and therefore with similar capacity? If you have no better quesses, maybe it's worth to measure those 3 capacitors out for a hint.

GigAHerZ wrote on 2026-03-03, 12:46:

Maybe C6, C7 and C10 are for similar function and therefore with similar capacity? If you have no better quesses, maybe it's worth to measure those 3 capacitors out for a hint.

Unfortunately the vinegar and IPA I doused the card in to neutralize and clean the extensive battery damage erased all markings that may have still remained on these ceramics. Even if I remove them, I do not have the tools to measure their capacitance 🙁

I can recommend the cheapest "Multi-function Tester - TC1" as component tester or "Zoyi ZT-102L" multimeter with capacitance and inductance measurement capabilities for quick checks like this. Each cost well under 20€ from china. 😀

GigAHerZ wrote on 2026-03-03, 13:22:

I can recommend the cheapest "Multi-function Tester - TC1" as component tester or "Zoyi ZT-102L" multimeter with capacitance and inductance measurement capabilities for quick checks like this. Each cost well under 20€ from china. 😀

I'll add it to my shopping list, but that won't happen too soon so for now I'm still waiting to see if anyone has this board 😁

appiah4 wrote on 2026-03-03, 13:23:

GigAHerZ wrote on 2026-03-03, 13:22:

I can recommend the cheapest "Multi-function Tester - TC1" as component tester or "Zoyi ZT-102L" multimeter with capacitance and inductance measurement capabilities for quick checks like this. Each cost well under 20€ from china. 😀

I'll add it to my shopping list, but that won't happen too soon so for now I'm still waiting to see if anyone has this board 😁

The design is close to the 286/386 boards that were recycled across.
Probably other boards have the same components.
I'll check mine to see if there's a match.

Personally I love this minimal design boards, they look halfway into the future glimpsing back at the 8086 era.
Nostalgia 😀

Nobody seems to have chimed in in a few days, I'll just try my chances with a 22pf ceramic capacitor and see how it goes 😁

I also desoldered the corroded KBC socket and managed to destroy the ground terminal, so I'll have to bodge that to the PSU ground directly..

The battery terminals are also completely eaten away and gone so I had to remake the terminals and bodge them to where they need to go etc. It's not going to be super pretty, but I'm thinking it might actually get somewhere. Fingers crossed..

I'll post photos of the end result tonight 😀

P.S. I'm expecting a few more caps to go Kaboom! to be honest. Nothing appears shorted, but knowing my luck with tantalums a few more of them are liable to give up the ghost 😁

Ok, so replacing the damaged caps resulted in 2 more tantalums on the -12V rail and 1 tantalum on the 12V rail to go kaboom, so I went ahead and replaced all tantalums on the +/-12V rails.

The result is a bit sad. The board fires up but the POST analyzer gets stuck at 67 after staying at 65 for a bit. This is a 1993 AMI BIOS. I have found conflicting information about what 67 is but it appears to be Initializing KBC.

The KBC socket was incredibly corroded, I replaced the socket and I may have damaged something while doing that, or may have missed a damage that needed reparing. I'm not sure how to go about troubleshooting it now, though 🙁

The KBC is a MEGATRENDS MEGA-KB-H-WP which is, apparently, a clone of [ur=https://tvsat.com.pl/PDF/W/W83C42P_win.pdf]Winbond W83C42[/url].

I had to break out the scope and realized some Data lines were low.. a lot of continuity checks and some spagetthi bodges later, happy ending. 🥳

It would seem I destroyed the terminal on a few pins while desoldering the corrodes socket.. Oh well. Not gonna win beauty contests, but it has character and works. 😎