HP15C CE - Battery problem

[Johnh]

Has anyone changed batteries on an HP15C CE?

Mine is a year old, running fine, but I identified the following issue when I opened up the battery compartment yesterday to (successfully) do firmware and VoyagerSave updates. This was actually the first time opening the battery compartment.

The idea per the manual is that you can switch off, replace the batteries one at a time, and when you switch on, data is still preserved. On mine, if I remove and quickly replace the battery nearest the centre, all data is lost, like a full reset. The outer battery near the corner is not providing charge to maintain data. This is with new, tested batteries. I can however, remove the corner battery and actually run the machine and it works ok

Testing without batteries with a meter reading resistance, there is no connection from the outer battery’s lower ‘-ve’ connection, to that of the centre battery, (test range 2M Ohms), and with one battery in place in the centre position, no voltages are detectable at the corner battery slot, and using alligator clip and leads to connect the second battery, no current measured flowing through it either.

I think my corner battery is just not connected to anything? And its not just lack of contact battery to calculator. The calc runs fine on one battery, but this can't be replaced without data loss.

Can anyone comment or confirm?

ive also posted about this while getting the cable connection to work, on this thread:
https://www.hpmuseum.org/forum/thread-22103.html

But this battery issue is more basic I think.