My HP67 Has Melted!!!

[Maximilian Hohmann]

Hello!

(03-20-2020 11:48 AM)Ignatz Wrote:  Any idea what went on there?

The only thing that can cause a battery to get that hot is a large current draw. A short circuit or an "almost short circuit". Or an excessive charging current. Or, as in your case, a combination of the two: First the calculator discharged it's battery rapidly and when you plugged in the charger, it rapidly charged the already hot battery thereby heating it up even more.

To start with I would look at the power supply circuitry in the calculator.

Regards
Max