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I used F258AD, not F258. They’re from Philips.

There’s no marking or anything on the chips, even under the microscope.

I checked all the vias underneath the battery — they're all good. But I'm not entirely sure the new F258s are installed the right way, since there were no markings on them.

I ordered a Din-8 to Serial cable, to see if I can get an error code.

Isn’t that concerning ?

I'll check that with the microscope, thanks !

I figured out it's a problem with the RAM. Zebra pattern is normal, it's because I have TI chips at UC6 and UC7.

Here’s the board now

I replaced Y2 (32 mhz) too, didn't change anything :-/

Just replaced UE8 with a known working one, no difference. I also remplaced the sixth F258, no difference as well.

I have an other battery bombed board, but in worse condition… However this one shows a simasimac pattern at startup, not the zebra pattern.

The 32 MHz one ? Or the 32.768 kHz ?

Everything’s okay here, is just a little bodge since one pad was slightly broken. I already checked for shorts.

I already heard about that. I need a serial to usb cable ? Since a get a sad mac, it means that the cpu is reading the ROM content, right ? But I don’t understand why I got the zebra pattern and not the simasimac or sad mac pattern. For me the video circuitry is good.

The reset and developper switches work both.

I recently bought a battery bombed SE/30, originally just to salvage some components from the logic board. However, the damage wasn’t too severe, so I decided to try repairing the board. I replaced five F258D chips with new ones, and there are no visibly broken traces. I also washed the board...

I was recently given a non-working Macintosh II power supply to repair and use with my Macintosh II board. Someone already recapped it correctly, and every capacitor has the correct value. It tries to start but immediately shuts off, and the fan doesn’t turn on. When I keep holding the power...

I found the issues : R5 wasn’t correctly soldered and damaged, which explained that it couldn’t turn on via the power button, and replacing Q2 fixed the shutdown issue.

When I manually inject 5V to Q2, it starts up, and when I manually inject 5V to pin 4 of the power button, it starts up as well.

I also replaced UJ18 and UI18 with brand new HC132 chips, but it made no difference.