HP35 problem with a calculator, maybe due to a faulty charger

[aurelio]

(03-21-2021 11:07 AM)teenix Wrote:  

(03-21-2021 10:19 AM)aurelio Wrote:  Thank you Tony, CPU boards swapping was the first thing that came to my mind, but I also thought about the risk, however minimal, of being then with two 35 opened and, even worse, both not working...
Thanks for the advice, I measured the voltage and read, with my 8.5 V multimeter, where it should be from scheme 8.2, but I do not know the accuracy of my instrument and the tolerance allowed.
I measured on test points what I could measure with the multimeter i.e. Vss = 6.49 (expected value 6 V) and Vgg = -12.94 (expected value -12 V), what do you think of these results?

I think they are pretty good.

cheers

Tony

Well, if the voltage on test point is the one expected it means maybe that the PSU works properly, so what would be the next step in the troubleshooting?
What does it mean that if I use any of the numeric keyes, the calculator turns off, while clicking on the functions the display shows numbers that vary, from time to time, with different criteria?