battery on PCB of a Fujifilm X-M1 camera -- not recharging

I posted a thread a few days ago about fixing a Fuji X-M1 that will not power on.

I disassembled the camera and isolated the PCB. You can see a picture of one of these at this website:

http://www.aliexpress.com/item/Free...a-PCB-XM1-Mainboard-For-Fuji/32232619616.html

I am sure that power from the main (BIG) battery of the camera is reaching the PCB.

The (TINY) battery on the PCB reads 0.44 volts. It is supposed to read 3 volts

It's labeled: MS414GE. It is a rechargeable battery. The website for this battery is:

http://www.sii.co.jp/en/me/datasheets/ms-rechargeable/ms414ge/

Is it likely that the camera fails to power on because this TINY battery is not working properly?

IF SO, is there any way I can test to see if this TINY battery is the problem?

It is obviously failing to recharge. But maybe that's not because the battery is defective but because of some other problem.

It is out of the question to buy a new PCB -- that would cost more than a used X-M1.

I would be grateful for any help.

A Lithium battery does not last forever, when it fails then it must be replaced. But a lithium battery is destroyed if it is discharged too low. Maybe the charging circuit is defective or maybe the circuit that disconnects the load on the battery when its voltage is low is defective.

audioguru said:

A Lithium battery does not last forever, when it fails then it must be replaced. But a lithium battery is destroyed if it is discharged too low. Maybe the charging circuit is defective or maybe the circuit that disconnects the load on the battery when its voltage is low is defective.

Click to expand...

Many thanks for the comment.

According to the guys who sell the MS414GE re-charging batteries, this internal battery is a >>RTC / SRAM Backup<< type battery.

https://www.avnet.com/shop/us/products/seiko-instruments/ms414ge-fl26e-3074457345625990705/

The battery is now completely dead. No voltage across the terminals.

I don't know if the charging circuit is working properly.

However I did the following as a test. I soldered two wires to the terminals of the PCB board which correspond to the +/- terminals of the battery. These wires were long enough to remain external to the camera after re-assembling the camera. I popped in the user battery (the external battery) and turned on the camera. The cameras did not power on (no surprise...).

Then I measured the voltage across the terminals (where the dead MS414GE battery is positioned in the PCB). The reading was 2.98 volts.

I suppose this means the the charging circuit is working properly.

However, it also stands to reason -- maybe I wrong -- that the failure of the MS414GE battery is not the problem that prevents the camera from powering on.

The tiny battery is probably not expensive. Buy a replacement battery and solder it in to try it.