Ti-58c: Strange behavior

[Doctor_Jacek]

Goodmorning everyone,

After connecting my T-58C to an external NiMh battery pack and arranging the foam on the keyboard, the calculator came back to life.

If I run 2nd-Pgm 01 Sbr = after 30 seconds the display shows a 1.

If I run Pi (3.14xx) STO 05, I turn off the machine then immediately turn it back on and run RCL 05 I get Pi.

Same behavior if I wait 15 minutes before turning it back on.

All this could suggest that the calculator is working properly.

But if I wait about 30/45 minutes (or more) and I repeat the command RCL 05 I get a meaningless and non Pi number.

What could be the cause of this operation?

Could it be the electrolytic capacitor?

Regards