CharlieFoxtrot wrote on Yesterday, 17:38:

PcBytes wrote on Yesterday, 17:24:

CharlieFoxtrot wrote on Yesterday, 15:26:

That sounds like something that could be relatively easily repairable, though. Cracked solder joint on the chip legs or some components.

I've resoldered all SMDs that are between those ICs. Same behaviour.

Damn. Have you checked it under the microscope if there is some cracked SMD cap or resistor there besides reflowing the solder joints? It may be difficult to see those with a naked eye. It definitely sounds like there is a contact issue of some sort that prevents it from powering on.

I swapped all SMDs from another P3B with a snapped socket. Same behaviour. All SMDs are fine, checked under microscope as well.

It could be a hairline crack on a PCB trace.

Kahenraz wrote on Yesterday, 23:03:

It could be a hairline crack on a PCB trace.

Tinned all traces I could find to eliminate that possibility. Still the same outcome.

justin1985 wrote on 2025-07-11, 21:15:

Correct! It's not as dramatic as the sliding cover on the towers, but it's great to see IBM went to the trouble of fitting a damping mechanism - press the dimple and it very gently rolls open.

Thank you very much for going through the trouble, sir! Good luck with your gem!