Dead HP 35

[krazyk]

Just unpacked my in storage Lab Power Supply

Set the voltage to 3.8 Volts and set the current limit to 500mA and......

Suddenly Vcc jumped straight up to 8.15 Volts.

Vss still seems a little low at about 5.75 Volts and Vgg was 11.8 Volts

So finally the voltages seem okay eliminating the power supply components from being a problem.

Still no display and of course I now have a live readout of current flowing on the Lab PSU at 45mAmps.

Sorry Teenix but I should have unpacked this Lab Power Supply right from the start really as its just so useful now. Very occassionally when I handled the calculator the current jumped to around 300mA which was interesting. It may have been indicating a lack of continuity somewhere.

I have checked all of the gold connectors from the keyboard pcb but one appears slightly broken but well ABOVE the hole. I will try and post a picture tomorrow.

I am wondering whether it is an issue with power on reset as I had an Apple II motherboard fail to do that years ago. This might explain the 45 mA current usage. The engine of the calculator hasnt STARTED.

Kris