Main channel: This expanded Mac 512k came from the college Steve Jobs went to
Added 2025-06-30 21:33:25 +0000 UTCHello my patrons! Next up on the main channel I've moved to the 16bit era with a sad Mac 512k. There's nothing too complex about this repair, but it was a fun diversion and a fun exercise to think through the fault and figure out exactly which chips were causing our issue. On top of that, the exact fault was a curious one, one I hadn't personally run into before. So sit back and enjoy some light hearted troubleshooting of a classic Macintosh.
Thanks for all the support!
Direct link: https://youtu.be/YRwh6NcrltY
Comments
Static or ESD is not really possible on a board inside the machine. This could just be a failure mode of the way Sanyo made these chips. DRAM from Japan back then was nascent and they were still learning how to make the chips reliably.
Adrian's Digital Basement
2025-07-01 15:26:37 +0000 UTCSo those failed RAM chips essentially all had the highest address pin go bad? I wonder if the board got zapped with static or something to cause that.
Brad Martin
2025-07-01 01:32:25 +0000 UTCNice 512Ke! Awesome RAM expansion board. Glad it’s all working-can’t wait to see the Plus!
Markintosh
2025-06-30 22:29:57 +0000 UTC
