HP42 Machine reset - what's going on

[Guenter Schink]

Recently I acquired an HP42S on TAS. It was rightfully announced as defect to show "Memory Reset" at arbitrary intervals.

The HP42S was only about 30EUR (33US$). That made me think, no risk no fun!

Unpacking the device and switching it on made it beep and show "Machine Reset" right away, so no surprise. Consequently the seller deserved a positive feedback, as the description was awfully exact.

First positive sign was, pressing between the display and the keyboard, made the noise stop and I could make the HP42S work as expected for a while. But then the nasty behaviour showed up again.

Asking the everything knowing WWW for "machine reset HP42S" I found a few threads, most of them at hpmuseum.org, specifically for this problem, but nothing was really enlightening.

Restarting the calc every now and then, putting it in coma mode, running it in almost endless loops, pressing it here and there, caressing its back, and what have you, made it obviously work, for what reason ever.

Now, for 4 days it worked flawlessly. Never showed the nasty "Machine Reset" again. I'm wondering: did my magic hands rectify the situation, was there some magic action I did, or will I simply have to wait for the next failure to occur?

Thanks for reading my report so far,
Günter