An internal battery is only for keeping settings, clock, etc. It has nothing to do with powering the camera.
Even if got a hold of the service manual, the likelihood of needing a part is high. Where would you buy such a part? You could buy another dead A345 for parts, but you can buy a used working A345 for less than $20.
Ordered Y screwdriver tool to open up the camera.
Is there an internal watch battery that is shot?
Batteries and contacts are ok.
Anyone have the PDF for the service manual?