HP-97S 'Proto' ?

[Alexanderpentagon]

(08-19-2023 03:27 PM)TellyS Wrote:  I have an HP 97S that i think is an original. It was not working, so I replaced all ICs (with the exception of the one that was HP custom ROM) and the calculator worked great. I have attached some before/after pictures, if they help. These are from the top board. I don't remember why I did not take any pictures of the second board. Maybe a left that one alone.

Anyway, included for reference. And I also have the replacement IC list, if ever needed.

From Your photos I can see You have a release B of PCB , I Have a A2 reiease... so it's compatible with my 'proto' /pre-series theory.
Thank You