WP 34S will not turn on

[jebem]

Thank you for sharing your good knowledge here, Barry.
Very detailed and useful and helpful information.

I didn't meant to contradict you with my post, but just complement it as i don't know what is the OP background knowledge in electronics. Indeed he mentioned to have used an external fixed 3V power supply but it is easy to have more than that applied to the machine depending on the quality or precision of the used equipment.

Again, thank you from my side.
I allways enjoy and learn from your posts.