Can you post some pictures of the system maybe someone can spot something that might of gotten missed. Did this just start happening randomly? I'd start with the very basics. Check your bios battery as I've had system either act dead or misbehave in some crazy ways. Also check your power supply to make sure you getting proper voltages on each rail. A failing power supply can cause the system to become flaky and hang and other random problems.

Yes, I will get some pics in the next day or so and post them. Thank you for the starting points also

Sorry for the delay and the picture quality.

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70ties technology, I dont even see a computer module in there, must be hidden somewhere deep inside

CheezyBroccoli wrote on 2024-04-29, 02:52:

All I’ve done is a visual for solder, capacitors, etc

Usually the electrolytics get better when heated, not worse, so it's a bit odd that the system seems to work fine only when cold. So the logic board is in the same case with the monitor? Could be some noise from the CRT system is upsetting the logic.

Resolder the flyback and perhaps the transformer and storage coil if the PSU is of the switching type. Test or replace electrolytic caps on the PSU and logic board(s) - don't skip the little ones, in fact these can dry out without any external signs. Be suspicious of any semiconductors that get hot but are not cooled (esp. if the PCB got discolored). I've seen zener diodes go bad in weird ways, and sometimes even the rectifier diodes go open.

If nothing seems to help it might be one of the logic chips being very marginal. CMOS ones usually work or not (that is - it's not temperature related). I don't have much experience with marginals NMOS/PMOS but TTLs can and will degrade over time. Especially the early ones (no letters or S series).