HP-97 not Charging

[Geoff Quickfall]

Diagnosing over the internet is like trying to describe a new operating system over the phone without a computer.

For me, I check the following in order:

1. Any observable mechanical faults; leaky caps, burnt resistors, visible cold solder joints, oxidized solder joints (flat powdery grey (gray) look.

2. If no visible signs then the suspect circuit solder is reflowed.

3. If no success and in this case. Follow the voltage pathway starting at the HP 97 plug. Test on each side of the next component for voltage; capacitor, diode (of course only in one direction) until you find a zero voltage indication.

4) Use the HP 97 manual for test points and compare voltage requirements versus your indications.

5) it may be the first IC in line with the power supply.

And of course, let us know what you find!

Best of luck, geoff