Amiga 1200 losing time

[Captain Nemo]

My old Amiga 1200 is occasionally losing time. I replaced the RTC battery about a year ago so this shouldn't be the problem. When it first happened it lost a few hours, but most recently it went back to June 1996! As I say this has only happened twice in the last few weeks. The RTC is part of a Hawk RAM expansion board. I've left the Amiga switched off since Tuesday afternoon and will switch on again tomorrow morning (roughly 36 hours down time) to see if the problem happens again. I will probably change the battery just in case this is the cause. Could there be anything else causing this problem?
 
Thanks.
 
Nemo

[Captain Nemo]

Thanks, that could be it. I just powered it up after about 36 hours turned off and the time is correct. It's a strange one.
 
Nemo

[Captain Nemo]

It's certainly looking like that is possibly the problem. I'll see how it goes.
 
Thanks.
 
Nemo

[Captain Nemo]

Thanks for the replies.
 
Had the A1200 powered down for three and a half days then powered up and the clock has reset itself to 01.54, 20 June 1996, which is the date the Workbench partition was written to disk.
 
I'll buy a new battery today and see if that cures the problem. The current battery has only been in there about a year though and I'm told they should last about two years (CR2032 type battery). I suppose it could be a duff one.
 
Nemo

[Captain Nemo]

I've just replaced the battery with a new one. I checked the battery contacts and they appear to be good. I'll keep you posted.
 
EDIT: I measured the offload voltage of the old battery with a multimeter and it showed 2.96v. I understand that a fresh battery should be around 3.2v.
 
Nemo

[Captain Nemo]

Looks like it was a defective battery. Had the A1200 switch off for three and a half days then powered up and the time is still correct with the new battery installed.
 
Thanks for your help on this issue.
 
Nemo