HP21 problem

[PANAMATIK]

(12-18-2014 04:09 PM)MarkPalmer Wrote:  I'm sure most here already know this, but I see so many for sale with them being shown tested with all sorts of gibberish shown on the displays stating the calculator is non-functioning and it drives me crazy. Never operate a Woodstock series HP calculator being powered off the charger without a good set of rechargeable batteries installed in the calculator. Bad or no batteries at all while powered on with the charger can easily damage the IC's in this series of calculators.

-Mark-

Perhaps you don't know yet, because it is very new! See my post in "ACT available"

I made an ACT replacement chip for HP-21 and HP-25. You can repair your HP-21 now. It will work again after you charged without batteries and damaged the original ACT.

Bernhard