Hello there, i’ve three mac portable that don’t work correctly. both three have been recapped. the first one was initially working, then i’ve tried it after some years and it wasn’t anymore… after some reboots i’ve managed to make it boot but crashed when a sound was played, then after some days it stopped again to work and now it displays a black screen everytime. the second one gives me the question mark screen but then it plays a very chirp sound. the third one doesn’t boot and displays usually this pattern on the screen. What should I try/test? I’m running out of ideas, cleaned the boards a few times but nothing… they are running off a new 6v 4.5a battery and i’ve even tried a 7.5v 1.5a charger but nothing changed. thanks a lot.
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Three Macintosh Portables that don’t work
- Thread starter MrBlanchet
- Start date
I’d add that on the third one the area between the video - 68HC and misc glu ics gets a bit warmer than the rest.
maybe @techknight @SuperSVGA have already seen some portables with these symptoms? The first one is a mistery. I suspect it’s the hybrid since it started to work for some days and then after i -miserably- tried to boot via the floppy reader it went black again.
With regard to your third example - I had a Portable recently where one of the three 74AC244 latch chips had failed, related to floppy drive function. I swapped it with one of the other two latch chips and immediately had a display similar to that and no chime. Therefore, I wonder if one of those latches is causing the problem with the glue logic. The location matches the area you said is getting warm.
update… the second one had a broken via, its now fixed
i’ve found a capacitor on the back (c60) that is broken in half. will replace it the next week. it’s only a bypass capacitor but it’s very suspicious.
I have a 5126 that I have been working on for weeks now. Looking forward to seeing if you get these working. Mine is getting a black screen, backlight works. I found a few broken traces and fixed them, found some weird voltages on some of the mosfets, replaced a couple. It’s just hard to work on when. I don’t have the skills, and don’t know what I’m supposed to even see on the voltages.
Whatever you can find out, thanks for sharing.
Whatever you can find out, thanks for sharing.
