After about 30 years of reliable service, my HP 41CX all of a sudden and out of the blue also developed symptoms that resemble the ones described here. First, no reaction to the ON button at all, just ten minutes after I had used it totally normally before; then, first, I thought the batteries were gone, though replacing them didn't bring any avail. Pressing the PRGM, <- and R/S switch at the same time led to 'clx' in the display, followed by a '0, 00'. Batteries out and in again led to variations of this behaviour,some times I could enter a single digit, mostly not, but did not lead further. One of the battery springs (the one of the inner pair where the plus pole of the cell sits) showed a small patch of oxidation which could be wiped away with a glass brush. No help though.
My HP41CX has always lived on my desk, no harsh environment, no pushes, no droppings. After reading the descriptions here, I reckon it as pretty probable that it needs the described contact care procedure. Are there any tutorials or descriptions on YouTube or somewhere helse that make things even easier than described here? Expecially the opening of the housing and the proper disassembly would be interesting.
And what do you folks recommend as a cleaning medium? Water? Iso-propanolol? Or?
Thanks a lot in advance, also for keeping and taking care of this website. I still remember the time that HP sent me a quarterly user magazine after I head purchased my first HP 65 (after the HP55, which was my first, then followed by an HP67). The HP41 CX is still unbeatable (except for comatic phases like now).
Ulli aka longkeeler.
Don't try to fix it if it is not broken. And IF it is broken, please keep your fingers away!