What are these weird voltage readings?

hello rickcostel,

there can be many reasons of that behawior. You need to go back to basics. Remove the motherboard from the case and plug in the bench power supply. On the basis of the current load indicator, many interesting conclusions can be drawn.

In your attached video I can see some interesting instruments like Hakko-203 and Quick Air Station. This proves that you have a lot of experience and you will certainly cope with such a simple puzzle. Fingers crossed :-)

Hello. I have problem don't turn On. Check main board connector battery shorted. But last time sellphone working, how too find problem ? Something schematic diagram board elements. Thanks