Help... Cmos Batt Dead

[kyjet]

Hi guys. My M571 v7a is losing time. I changed to a Seiko 3v CR2132 Lithium batt and it seems to work fine for 2 days until the last weekend. When I boot up, I get this error message - CMOS Batt Low. But it's a brand new batt ! I can only think of 2 scenarios - either the new batt is "old" or there's something wrong with my mobo. I even tried to reseat the batt but same problem.

As a result of the above, I lost all my CMOS settings. Does anyone have their settings written down ? I have the following :-

- Off board sound (Realtek) and video card (Savage 4)
- 2 HDDs (Seagate)
- 2 CD-ROMs (I have 2, why not ?)
- PC133 128 MB RAM (Hyundai)
- AMD k62 500 (Yes, running at 500)
- Internal 56k modem (Connexant)
- PnP Network card (Myson)

By the way, I recently installed Win2k Pro and re-arranged my HDDs, placing the faster HDD as master instead as slave (stupid of me !). I don't know if that makes a difference.

Anyone, please helpppppp.

Cheers - kyjet sydney

[jim chase]

On the outside chance that you got a bad battery I would try another.

If it goes dead again I would be looking at doing something like done at this link http://www.rason.org/Projects/cmosbatt/cmosbatt.htm unless you have a warranty on the M/B.

The CMOS optimal settings should be a good starting place and then redetect the drives unless optimal sets the drive detection to Auto (I prefer detecting the drives).

Jim

[brad]

Good work Jim. That's a typical basic diagram of the trickle charger used on most mobos of the genre, works the same way as the mobo circuit and will do the job as well.

If the diode opens, the battery doesn't get a charge at all. If it shorts, the battery gets a charge when the system is on, but it will discharge through the psu and MANY other mobo paths when the system is off.

I can't remember what the Dxx diode id# on the mobo is, but it is among the group of diodes near the twin-AT style power connectors. Not too hard to find which one may be bad with a DMM.

Brad

[mike fischer]

I had a m571 which started by loosing time, then cmos settings, then reqiured multiple trys to boot
until it would not boot. I attributed it to the cheap capacitors, and after sitting in the junk box corrosion started appearing on the top of one of the caps. I haven't changed it yet but if I do - I will replace all of them in the p/s section.
DigiKey has suitable replacements of a real brand - approx the same uf value and same physical dimensions.

[kyjet]

Hi. Thanks to all who responded to my cry for help. I tested my new batt and found that it's ok. I gave the batt a good polish and stuff bits of paper around the cmos batt holder so that the metal contacts are "tighter" around the batt. Whola, works like a charm. But still losing time though. Don't mind losing time as long as my mobo works ! By the way, Win2k is GREAT !!

Cheers

kyjet sydney