I have an old Texas Instruments pocket calculator, for fun decided to get it working again. It is strictly a NiCd powered calculator, no alkaline recommended.
The charger is the 9130, says output 6 VAC, 175 mA. Tested with unloaded output measures 9 VAC, with a 20k ohm per volt VOM. Before I crack open the power supply case, is this "correct?" I don't like the sound of AC charging NiCds. Should be some kind of filtering in there that might need repair.
The SR-50 takes 3 NiCds, no circuitry in the very basic battery pack, will use new NiCds. Maybe I should get a new charger. The battery pack is required for operation of the calculator.
What is a good way to test the charger under load?