T23 Intermittent CMOS Date/Time

[peternsomerset]

Hi,
I have had this intermittent problem for years.
Here is a brief history:
Bought T23 (very good condition) and found I had the problem also main battery was only 50%, changed both.
Problem did not seem so bad but developed again, and checked to find M/B CMOS socket had "lifted" slightly.
Re-soldered and problem persisted, assumed socket problem again so eventually replaced M/B!
Same problem again, its now got a lot worse but I am at a loss to know what could be wrong.

Any advice appreciated as I do not want to throw it away.

FWIW I am running a dual boot (grub) Fedora 9 and XP box but this should not be relevant!
CMOS battery checked OK at 3volts.

If there is a way to monitor this supply to the chip with the battery connected I would like to know!
I assume I would have to completely dismantle the case to do this?

The only thing I can think of. is that the actual plug/socket is not connected properly, but I am now clutching at straws!

Thanks

[rkawakami]

Welcome to thinkpads.com!

By changing both the battery and motherboard, it would seem like you have eliminated both causes for losing the system time. Are/were both CMOS batteries ones where the leads were welded to the battery? Or are the leads simply taped to the button battery? While a 3V reading usually indicates that there's enough current being provided, have you tried another (new) battery? I'm also guessing that you are getting the 270 or 271 boot error which would indicate that the BIOS has totally lost all of the time information, correct?

[peternsomerset]

Hi rkawakami,
In reply to your questions:
I cannot find my old battery atm so cannot say if it has welded wires, I did not realize they are sometimes supplied taped!!
The one fitted has an IBM number on the yellow plastic shrink cover, it seems welded but I need to check and confirm.

I have not yet bought/tried another battery - that was to be one of my next options if no there were no other suggestions!

Yes, these are the errors (mostly 271)

Thanks for the welcome

Regards

[peternsomerset]

Hi,

I just tried to to see if the battery was welded but it seems to have the yellow shrink wrap really stuck to the battery and as I do not want to destroy it (yet) I will wait to see if it goes wrong, if it does I will but a new battery before dissecting it!

Does anyone know if the battery is connected directly to the memory or are there some components in between!?

PS just tried it 3 times and it worked!

Thanks

[RealBlackStuff]

If your CMOS battery has the yellow shrinkwrap, and has the IBM P/N or FRU on it, the contacts are welded.
However, even if the battery shows 3V it may still be an old(er) battery, that could be shortly before its demise.
The few dollars or pounds that these batteries cost new, are a good investment to keep your lappy happy for a few more years again.

As nobody (outside of IBM) has ever seen any diagrams of the motherboards, it's unknown how these batteries connect to the chip that stores the date/time and other info.