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I previously requested 12C calculators for reverse engineering to improve the accuracy of Nonpareil, and thanks to the generosity of folks here (especially Mark), I have been able to start that work. I think it would also help if I could get one or more spare 41C/CV/CX logic boards. I don't want anyone to sacrifice working calculators for this, but if anyone has a spare board (perhaps as a result of installing Monte's 41CL upgrade board) which they're willing to sell, please let me know.

The plan is to build a custom Nut PC board for reverse-engineering purposes, physically much larger than the 41 board, but containing most of the components from it, along with additional sockets and connectors for convenient logic analyzer and oscilloscope probing, and connecting custom interface hardware.

Thanks!
Eric

I have a spare 41CX board. Unfortunately, the time functions do not appear to be functioning...

e.g. SETIME/SETDATE executes normally, but executing TIME/DATE, the display only shows 12:00AM and 1/1/1970 MON respectively.

PM sent.

(03-14-2023 02:38 PM)Mark H. Shin Wrote: [ -> ]I have a spare 41CX board. Unfortunately, the time functions do not appear to be functioning...

e.g. SETIME/SETDATE executes normally, but executing TIME/DATE, the display only shows 12:00AM and 1/1/1970 MON respectively.

The problem might just be a failure of the crystal, or the connection to it. Of course it could be the timer chip, but I think the crystal is a more likely failure.

One might reasonably expect that if the crystal failed, the time could be set and read back, and just not increment. However, almost everything inside the timer chip needs the crystal working, so I suspect that the crystal is probably necessary even just to set the time and reading it back.

Thank you for all the boards you've provided in support of my reverse-engineering work!