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| 512k flup flup |
Posted by: imactheknife on 2023-11-10 19:21:04
Picked up some cheap non working macs. One is the 512k that i didn’t have in my collection. Pulled apart, tried logic board in another chassis, worked perfectly. So focused on analog. Blown fuse, so replaced. Nothing. Recapped what i could. Didnt have the 3.9uf 25v or the small axial caps. It now macs a flup flup noise but nothing else. Is the other caps the culprit? Or something else? Is this red cap a 3.9uf cap? |
Posted by: bibilit on 2023-11-10 23:33:22
Flup flup sound can be either the PSU trying to kick in and not being able to, or a bad solder joint or the Optoisolator |
Posted by: imactheknife on 2023-11-11 06:07:27
Flup flup sound can be either the PSU trying to kick in and not being able to, or a bad solder joint or the Optoisolator Ok, great. Which area is the optoisolator? Thanks! |
Posted by: desertrout on 2023-11-11 08:29:07
Ok, great. Which area is the optoisolator? Thanks! Right under the speaker - U3 |
Posted by: bigmessowires on 2023-11-11 09:31:56
From my understanding of it, flupping usually means you have a short-circuit somewhere. The PSU can't start up because it goes into instant overload. See the discussion beginning on page 117 here: https://vintageapple.org/macbooks/pdf/Macintosh_Repair_&_Upgrade_Secrets_1990.pdf |
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