I have a HP41C that until recently has been operating without any issues. Recently I have been unable to utilize the "USER" mode of the calculator. When the "USER" button is pressed it appears to have no affect (does not indicate user mode on display). Not sure whether this is a hardware or software issue. All other buttons work properly. I have disassembled the device and internal components look to be in good condition (no corrosion). I have tried to reset the calculator but this did not seem to resolve the issue.
Any suggestions.....