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HP-21 malfunction - Printable Version

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HP-21 malfunction - Moggul - 11-14-2019 02:40 PM

I recently acquired an HP-21 and am trying to resurrect it.

The battery pack was in very bad shape so when connected to the charger the display was erratic, showing a flickering 0 in the rightmost digit. After installing fresh rechargeable batteries the display showed a single strong 0, and now it shows all 0s without any flickering (see pic sequence). This is both when connected to the charger and when powered by the batteries alone.

[attachment=7812] [attachment=7813] [attachment=7814] [attachment=7815]

Is the calculator resurrectable or should I go the Panamatik route?


RE: HP-21 malfunction - Harald - 11-14-2019 03:10 PM

This is almost certainly a dead ACT. A PANAMATIK kit is the best solution.

RE: HP-21 malfunction - Steve Simpkin - 11-14-2019 03:49 PM

Connecting the charger with a bad battery pack (or no batter pack installed) is one of the quickest way to damage one of the HP-2X (Woodstock) or HP-3X (Spice) series calculators. Many collectors charge the batteries externally (or use non-rechargeable batteries) just to be on the safe side.

RE: HP-21 malfunction - ignazio - 11-15-2019 12:09 PM

PM sent.