RetroVein wrote on 2026-05-20, 16:56:

Well, the motherboard I had the issue with is a late socket 3, so probably around the same age as yours socket 5, and very much free of any capacitor plague 😀

Yep, I checked your Lucky Star LS-486E rev.C2 motherboard in TRW site. And that's why I draw a parallel with my own similar experience with the two socket 5/7 motherboards of the similar age.

From my own experience the electrolytic capacitors used during '90s and backwards are all purpose (no low ESR, no ultra low ESR, no polymer capacitors) aluminium electrolytic capacitors and they last much longer, than the ones produced from the early 2000s until now (excluding the Chineese brands with the fake electrolyte formula from the early 2000s, which sometimes fail for a couple of months). If the capacitor is not visibly leaked or bulged, there's no need to be replaced just because it's "too old". Unfortunately dried electrolytic capacitors can not be determined just by eye and without desoldering and measuring of their electrical characteristics. But while used in normal working conditions most of the electrolytic capacitors from "Ok brands" can last and serve for more than 30 years.

Update. Just in case someone gets until this point.
After swapping the single SIMM module, the problem came back! Continuous fast beeps, same code 40 0D.
Now, even restoring the same SIMM module in the exact same socket, the motherboard doesn't work anymore.
If I find a solution, I'll post it. So far, it remains a mystery.

RetroVein wrote on 2026-06-04, 14:43:

Update. Just in case someone gets until this point. After swapping the single SIMM module, the problem came back! Continuous fas […]
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Update. Just in case someone gets until this point.
After swapping the single SIMM module, the problem came back! Continuous fast beeps, same code 40 0D.
Now, even restoring the same SIMM module in the exact same socket, the motherboard doesn't work anymore.
If I find a solution, I'll post it. So far, it remains a mystery.

Hi, I'm sorry that after solving the problem, you went back to the starting point, or even worse.
For my part, I could assume that the problematic RAM caused a failure (somewhere), in the past it happened to me with a VX that after changing RAM, the card no longer worked, unfortunately I never understood what went wrong, so if you can make it work, I would be quite interested to know what the solution is.

PC@LIVE wrote on 2026-06-04, 19:14:

after solving the problem

but the problem wasnt really solved, it just luckily randomly vanished

Since it happened after another plugging/unplugging session mechanical damage hypothesis got even stronger. I would start poking and bending things until it boots again, then look really closely at the last poked spot.