Hi;
Renato pointed out a common procedure that, in most cases, work perfectly well.
But as you have a [MEMORY@@@@@@] display, intended to be a disguised [MEMORY LOST], I must warn about the possibility that you may also have cold soldering OR bad contact in some chips.
I have a fullnut 41C that does not work anylonger, and I surelly detected one ROM (ID 1LE908) that is faulty and, when installed in other calculators, shows the following problem:
- if you hold any of key you'll have a brief [CLX @ @ @] and [NULL @ ]
- if you use any key normally, it generates a [NONEXISTENT] message.
If you have the 1LA701 RAM as a fulty IC, [MEMORY LOST ] is displayed constantly, and you'll see a brief blinking (should see it in some twisted angles against reflected light), one for each second (1 Hz).
If yours is a halfnutt, nothing of what's written above applies.
I would like to help, if I kow how.
Success.
Luiz C. Vieira (Brazil)