68kMLA Classic Interface

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Troubleshooting a broken M0110A Keyboard?
Posted by: dv- on 2025-10-09 10:21:34
Anybody have (or know where I can get) wiring diagrams for a Mac Plus Extended keyboard?

I have one that's just a doorstop; other keyboards work fine with the same Plus / cable, but this one does nothing. I'm specifically curious about how to test that big microcontroller. (Would I need, like, an oscilloscope app?)

The contacts grid seems to check out alright, so I think the traces on the board are ok (a few scuffs and scratches but continuity is good.)

I replaced the two barrel caps; the resistors checked out ok, per my multimeter. Resoldered everything else just 'cuz.

I've read that if they're unplugged/plugged back in during operation, or used with an incorrectly wired headset cable, they can very rarely get fried - is there any deeper info on what happens when that occurs?

TIA
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