IBM ThinkPad R40 CMOS Battery

[ThinkPad560X]

My ThinkPad R40 CMOS battery doesn't want to hold the time/date and have to keep entering bios to adjust it every time I attempt to turn it on. I replaced it with a brand new one and It still isn't holding.

[rkawakami]

Verify the following:

- measure the voltage of the battery at the pins on the (tiny) connector; it should be 3V DC or slightly above
- inspect the socket on the motherboard to see if it is loose or damaged
- insure that the connector is firmly pushed into the socket on the motherboard; it's keyed to only go in one way so you should not have to press all that hard

[ajkula66]

I don't recall whether that applies to R40, but I do remember that R3x ThinkPads used a different CMOS battery from all the others, probably because they were built by Acer, as was R40.

You may want to verify that you have the correct battery first...

[Bikerbob]

So did you solve this?

I have the exact problem on the same model machine.

I have replaced the battery.. opened the old one.. just to make sure I was using the same battery.. yep.. no issues.

SO do I have to pull the main board and do some reflow on the battery pins?

James

[ThinkPad560X]

No I still have to keep my R40 connected to the AC Adapter at all times or I will have to keep entering bios and set time and date every time. Its anyoing. I even replaced the CMOS battery on it.

[Bikerbob]

Yep, same with this machine, I know the battery is good, I have tested it, the old battery was not good.. I assume it must be a solder joint.. I really dont want to take the board out just for that..

Funny how even a good main battery does not keep the cmos eh? YOu need the AC to keep it. I would have thought that it would draw from the main.. if not hooked up to the ac.

wish there was some kind of circuit test that could be done to see if the pins are connected to what they need to be.

James

[ThinkPad560X]

I got a brand new main Battery for my ThinkPad R40 and the Battery charge light is amber yellow for charging. The battery Maxi shows 0% and doesn't charge the battery. And the new CMOS battery don't work. Every time I have the laptop off the AC and plug it in. It brings up the Time and Date Error and have to enter the time and date everytime unless I keep it pluged into the AC at all times.

The Same problem goes for my ThinkPad G40 but the CMOS battery is fine. main battery don't charge but shows the amber charge light. and there both new batterys.

[RealBlackStuff]

Are those batteries original IBM/Lenovo stock, or cheap Chinese knock-offs?

[ThinkPad560X]

My R40 is IBM and the G40 is I think an energizer