Tantalum Capacitors, what I've learned

[Dwight Sturrock]

(05-07-2021 04:42 PM)Dreato Wrote:  Why did these tantalum caps test good but still fail in the circuit? I don’t know. I do know that next time I open a classic or Woodstock series or HP97 calculator, the tants are all gonna be swapped.

Questions, comments or corrections are welcomed.
Best Regards,
Dave

I checked several capacitors with my Fluke on capacitance setting, also measuring across the capacitor with another meter. It looks like the Fluke uses a very low AC voltage (or pulsating DC) possibly <10 Hz. An oscilloscope could confirm this.

Meters sometimes give results different than real world scenarios. Sometimes the reason is the difference in voltage between the test equipment and the actual circuit.
Sometimes an oscilloscope can clear up some ambiguity depending on the measurement being made.