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help with Mac Plus vertical bars?

Posted by: asentientbot on 2026-03-10 17:19:37 Hi, My friend just got a Mac Plus, which was dusty but not obviously corroded anywhere; after cleaning and checking +5 V (4.98) and +12 V (12.15) rails, she powered it on and saw this: View attachment IMG_0797.mov With 1 MB and 4 MB of RAM from her SE/30, it shows these (respectively): All symptoms are consistent for the given RAM configuration, and she cleaned and tightened RAM/ROM sockets and tried swapping high/low ROMs to no effect. We've looked at this post which suggests bad RAM (unlikely given the above?), ROM, or the 6522 chip. It seems like a logic board rather than analogue board problem? Please advise -- any points on the board to check which would help indicate the issue? Are there other likely causes? Is replacing the 6522 or ROMs a reasonable next step? Does the consistent behavior with each amount of RAM tell us anything? Here's a photo of the logic board: Thanks!

Posted by: asentientbot on 2026-03-14 13:35:09 Just for anyone else who comes across this in future -- she went ahead and replaced the 6522 and now it's starting and showing a perfect flashing floppy icon!! It'll be a while before we can test further as the drive doesn't work, but a big step in the right direction ☺️

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