TI 545 EEprom

Trying to find out some antique lore.

I have a customer with a TI-545-1101 CPU. Every other week it looses it's program over the weekend. The battery is good, it just loses the program. I re-program and it's ok, I swap the CPU and the same thing happens.

I was thinking of trying a EEprom, this might help some.

Does any one know what the generic part number is for the eeprom?

Any other ideas??

google "TI-545 eprom"
siemens part # PPX:2587681-8022 for 545 128K

is it worth your time to try to find exactly what type of eeprom it is and where to buy ? not me.

Sounds like a power issue try putting the plc CPU on a UPS.
BTW 545-1101's are really really old. Good luck finding an EEProm