Posts: 130
Threads: 36
Joined: Jan 1970
Hi Jorge,
I'm assuming you realize that the HP25 is volatile, and if turned off, all registers and program memory are lost.
Otherwise, it sounds like a power continuity problem causing data to be lost, most likely the battery contacts...which need to be scrupulously clean in a woodstock. Also be sure the all contact points within the battery pack are clean also. And be sure not to connect the calculator to the AC adapter unless you're positive you have a good battery pack with good contact installed (this could over-voltage the machine). I personally never connect my machine to an AC adapter, period. With my 29C I sometimes have to "seat" the battery pack by pressing it in the direction as if to remove it, but stopping short of actually removing it.
Best Regards, Hal
Posts: 883
Threads: 17
Joined: Feb 2006
Enter a few program keystrokes. If, upon review the operations change back to 13 00, the RAM IC has failed. Unfortunately, the only replacement source is from another 25.