|HP 41CX locked in program mode|
Message #1 Posted by Steve Leibson on 2 Oct 2009, 7:37 p.m.
I have a friend who gave me his mint-looking HP41CX. He couldn't get it to work any more. These handhelds aren't my specialty but I had a look. The batteries were badly drained. Some so low they measured 60 mV of reverse polarity. I got some new N cells, put them in, and the calculator came up with "memory lost." That solves that, I thought.
Not so, in seconds, the 41CX went into program mode and became unresponsive to most keys. The run/stop key produces a display with one "0" on the left and two zeroes on the right, for as long as I hold down the run/stop key. I've taken out the batteries, shorted the battery terminals, opened the calculator, shorted the electrolytics, put it together again, run the resent sequences, tapped it lightly to reseat anything loose, and rattled my beads.
For a brief moment, I could enter a short sequence (2 enter 2 x) and got the right answer (4) and then the 41CX popped back into program mode. I'm suspecting a short in the keyboard. Probably the PRGM key.
Any clues as to what's happening and what's to be done? I've seen nothing like this in the archived forum stuff, but it may be too far back.