IBM thinkpad 2647 CMOS battery failure ??

IBM thinkpad 2647 CMOS battery failure ??

Post by adyke » Tue, 17 Oct 2006 01:25:33

What kind of error messages result from a failed CMOS battery on a

I'm looing at a dead ThinkPad 2647 laptop. When I power it up I get
PCI errors and no I/O devices seem to be found.

When googling for the hardware manual to find out how to remove the
disk to recover data I'm reminded of the CMOS battery. It's been many
years since I saw a dead battery make a mobo lose it's mind and I
wonder if it's worth replacing the battery (It's an FRU) before I
declare the machine dead.

Comments ?

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IBM thinkpad 2647 CMOS battery failure ??

Post by BillW5 » Wed, 18 Oct 2006 04:42:11

Well I believe it depends on the BIOS manufacture and the version number
what it will do. Many desktops as well as laptops the clock will run
faster and faster as the battery gets weaker and weaker. Too weak and
the clock won't remember the time and date. And they will usually act
like you just hit restore to factory settings. Which will at least be
useable most of the time.

Can you get into the setup at all? If not, bummer! There are some
manufactures that play a dirty trick if the CMOS/Clock battery dies. As
they won't bootup at all. And I seem to recall the trick is to replace
the battery and then do a hardware reset (by jumping pins). Sorry I
can't be more helpful! :(



IBM thinkpad 2647 CMOS battery failure ??

Post by SMS » Wed, 18 Oct 2006 10:39:20

It's very rare for a CMOS battery failure to cause a problem like this.
The CMOS battery only powers the RTC/CMOS when the system is off AND the
battery is out AND the power is disconnected. On a desktop, with the
advent of ATX power supplies, the RTC/CMOS is powered by Vstby, as long
as the owner doesn't make the mistake of turning off a power strip that
the machine is plugged into.

Still, if you can find the CMOS battery it wouldn't hurt to replace it.