Thenk you all, especially Matthias, for that detailed information and instructions.
I now have the similar problem with my PB740, and would like to start from the battery replacement.
Could anybody please recall how big is the battery slot actually? I found
this battery, it not that thick (3.8mm instead of 5), but 2mm longer than original one. Are that 2mm critical, or original battery somehow loose in the slot?
I'd like not to disassemble the device before replacement arrived, I've lost so many small parts from other devices already
Thank you!