In this TI-66, memory contents were randomly altered. Every attempt to read from memory yielded a different result, at all program/registry locations. Examination of the circuit revealed that the memory is an obsolete off-the-shelf chip: a Toshiba 5514 C-MOS chip with 1kx4 bits of capacity. I was able to acquire replacement chips from a UK supplier and repair this calculator; it now works like new.
Bad memory in TI-66 (case 1)
