HP-41CL setup troubleshooting


Hello HP-41CL fans,

I bought a 41CL circuit board about a year ago to Monte. I only found last month a fullnut (2422S...) able to receive this jewel.

This morning I read (again) the manual before proceeding, but in a relative hurry, I didn't test the donor. :/

Well, I did everything like everyone. I didn't overtight the screw, but put some rechargeable batteries instead of fresh ones (:/, again?) and started to setup the circuit board:

1. MEMORY LOST appeared normally;

2. After Backspace (<--), XEQ ALPHA MMUCLR ALPHA did apparently the job;

3. ALPHA YFNZ ALPHA XEQ ALPHA PLUG1L ALPHA did what it was supposed to (well I suppose too...);

4. When I operated XEQ ALPHA MMUEN ALPHA, display stopped with this 'XEQ MMUEN'. I think it lasted about 1 minute; then the 'U' began to fade and this fade stopped again at least 10 seconds; I tried to turn the calc off, but no key were responding.
I then decided to remove the battery pack because I suspected a low tension - and remembered I had another one fresher :/

After many different tests, I am at this time unable to do the CL board operate properly: it simply doesn't work anymore - or seems so.

The CV too. Back with the initial board, it doesn't work.
I trust the previous owner (a friend of mine) who sold me this CV knowing the aim of the operation.

I have two questions:

1. Is the CL board definitively out of order?

2. Did I do something wrong?

I don't want to disturb Monte about this - but maybe he is reading this... - and prefer to warn everyone about possible problems due to improper manipulations.

Any help would be very appreciated.



Quite a few things need to be working for the MEMORY LOST to appear, so I expect that the board is fine. The issue almost certainly is due to a bad connection somewhere between the battery and the CL board: where the batteries connect to the Port/Battery block, where the Port/Battery block connects to the main circuit board, or where the main circuit board connects to the CPU board. Since the display stays active, I would first suspect the connection between the main circuit board and the CL board.


Thank you Monte, I'll check in that direction.

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