HP41.org

Hi,

After many years of happy use - my HP41C has finally decided not to work . It was bought new in the 1980's and the serial number is 2030A00264. I replaced the batteries with a new set and it will not switch on at all. For a while with the older batteries it was switching on with some trouble but now does not respond at all.
Any help would be greatly appreciated!

I don't know what the solution is, but I've heard http://fixthatcalc.com/ does an outstanding job of fixing them.

Thanks - it looks like a good company. It is difficult though to know what might be wrong and therefore whether an HP specific chip has died or that the on/off key is dead. They say they cannot repair these faults

The on/off switch is repairable, but it's rather drastic "surgery". Are your battery contacts in good condition ?, i.e. not corroded to any extent ?

If you're willing to disassemble the calculator yourself there are a couple of things you can try :
1. Just behind all switches there is a small hole through the circuit board, try a squirting a small amount of good quality circuit board cleaner into the hole, then "exercise" the key a little. Let it dry before reassembling.
2. Clean all the contacts with a good circuit board cleaner and reassemble.

Just make sure the circuit board cleaner is the type that leave no residue.

Cheers,
John