Hi, I have a 29c with rebuilt NiCd battery pack in place and the 29c is attached to a charger.
Even if battery is in place and charger attached, the 29c will usually power up and display "Error". A Clx and then the calculator works fine. If I turn the 29c off and then back on again in less than a minute or so, it retains values that had been stored before the power off, even under just battery power. However, if I turn the 29c off and let it sit powered down but with battery still in place and charger still attached, it displays "Error" again and the continuous memory contents are gone.
Otherwise, the 29c works fine.
Any experts know what might have failed on the 29c