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!

Most likely the chipset bga balls.

Since it should be leaded solder a good flux, preheater, and hot air station might do the trick.

Obviously a reflow isn't as good as fresh solder but the degree of difficulty between a reflow and reball is too high for most casual solderers.

myne wrote on Today, 04:39:

Most likely the chipset bga balls.

Since it should be leaded solder a good flux, preheater, and hot air station might do the trick.

Obviously a reflow isn't as good as fresh solder but the degree of difficulty between a reflow and reball is too high for most casual solderers.

Agree, that is probably the only possible issue left if all the surface solder joints are pretty much now checked. Reflow is definitely worth the shot.

myne wrote on Today, 04:39:

Most likely the chipset bga balls.

Since it should be leaded solder a good flux, preheater, and hot air station might do the trick.

Obviously a reflow isn't as good as fresh solder but the degree of difficulty between a reflow and reball is too high for most casual solderers.

Would you apply flux around the edges of the chip and blow it underneath with the hot air gun as it liquifies?

Insomnia and ebay are a dangerous mix.

I just ordered an ASRock 775i65PE motherboard and 2 SL9KE 3.4GHZ P4 processors. I'm hoping one of the two will be stable at ~4.5 or so.

I really need to stay off ebay at 3:00AM. 🤣

Haha yeah, and when you wake up "oh no what did I do". I had a few moments of those...

I auto-transfer a set amount to my virtual wallet each month and that's my retro budget. I can spend it all in one month or save it up to buy something big but never exceed that amount. Once it's gone I'm off the shops until my next paycheck. I had to make that rule after I spent $500 on various e-junk in a matter of weeks but didn't really need any of it. 😁
Now I only buy things I really want.

asdf53 wrote on Today, 07:39:

myne wrote on Today, 04:39:

Most likely the chipset bga balls.

Since it should be leaded solder a good flux, preheater, and hot air station might do the trick.

Obviously a reflow isn't as good as fresh solder but the degree of difficulty between a reflow and reball is too high for most casual solderers.

Would you apply flux around the edges of the chip and blow it underneath with the hot air gun as it liquifies?

Yeah. But you won't have to blow it. Surface tension and capillary action will work their magic.
Recommend low/no clean flux

Thanks! I got it to work with a mild 365*C reflow on the southbridge. No preheating as I don't have one nor the means to get/DIY one.