Took me 11 hours over two weekends to figure out one dead column on an IBM Model M

Reese Hart · 2026-10-27T20:20:04.784378+00:00

I picked up a Model M from a surplus sale at the university in Athens for $15, and it had one dead column of keys, the whole 4/5/R/T/F/G/V/B strip. I figured it was a dirty membrane or a loose ribbon, easy stuff. Nope. I pulled the case apart, cleaned every trace with isopropyl, reseated the controller ribbon three times, and it still would not type. I spent about 5 hours the first weekend testing with a multimeter and swapping in a spare controller from another board I had sitting around, and it made zero difference. Second weekend I finally traced it with the bolt mod guide and it turned out to be a cracked trace right at the ribbon connector, hairline crack you could barely see under a magnifier. I soldered a jumper wire across it, and it works now, but a job I planned for one afternoon ate 11 hours total. Is there a better way to test these traces before pulling the whole thing apart, like some cheap continuity trick you all use?

The Community Guide

Loading…

Took me 11 hours over two weekends to figure out one dead column on an IBM Model M | Bent Key Club - The Community Guide