Advice for a recalcitrant 29c

[teenix]

Just looking a bit deeper, at power on ROM0 executes initially, then ROM3 and DS1 are responsible for the Error display.

RAM register 46 in DS1 is tested for the 56 bit value 03493428400200 at power on. If this value is not there, then all RAM is cleared, that value is stored, and 'Error' is displayed

Assuming the battery is ok, on the next switched power cycle, that value will still be in RAM (assuming ROM and RAM are functioning OK) and the test will succeed, so RAM is not cleared and the calculator continues as normal.

cheers

Tony