HP-41C - Memory lost

[rprosperi]

(02-01-2023 07:26 PM)AndiGer Wrote:  My guess - especially if it‘s a made in USA 41C and therefore holding the CPU by nuts - some corrosion under the I/O port or weakness of the „foam“ under the I/O port

Only the very early 41C units used nuts to retain the boards. I believe they switched to other methods before the end of 1979. Pretty sure Geoff Quickfall posted here some years ago with exact details.