| My device was sitting untouched, counting away at a low rate food experiment, when it suddenly began chirping, occasionally accompanied by high pitched beeping. Rebooting, factory-resetting, battery removal did not help.
Next thing was that the battery readout via my GeigerLog became only zero volts,
2018-01-28 09:33:04 DEBUG getVOLT: raw: 
but multimeter says 4.1V, though the counting still worked.
Next thing was that the counter's time was advancing only 2 sec for every 10 sec that passed:
2018-01-29 11:53:05 DEBUG Counter Time: 2018-01-29 11:41:06, Deltatime:719.0 sec
2018-01-29 11:53:15 DEBUG Counter Time: 2018-01-29 11:41:08, Deltatime:727.0 sec
2018-01-29 11:53:25 DEBUG Counter Time: 2018-01-29 11:41:09, Deltatime:736.0 sec
2018-01-29 11:53:35 DEBUG Counter Time: 2018-01-29 11:41:11, Deltatime:744.0 sec
and now the timer has stopped working completely, frozen at 2018-01-29 12:24:59:
2018-01-31 10:36:54 DEBUG Counter Time: 2018-01-29 12:24:59, Deltatime:166315.0 sec
2018-01-31 10:36:57 DEBUG Counter Time: 2018-01-29 12:24:59, Deltatime:166318.0 sec
2018-01-31 10:37:00 DEBUG Counter Time: 2018-01-29 12:24:59, Deltatime:166321.0 sec
2018-01-31 10:37:03 DEBUG Counter Time: 2018-01-29 12:24:59, Deltatime:166324.0 sec
It is still counting, and can be logged with GeigerLog in the Logging mode, but of course the history is complete nonsense, as the counter's DateTime-tag is always the same.
The only good news is it has stopped chirping and beeping
Has anyone noticed that kind of defects before?