Replace Toshiba M55 CMOS battery

December 9, 2007 7:58 AM

Mrs. mysterious1der's laptop (M55-S331) won't keep time accurately. I've torn apart and repaired (board swaps, not actual board level repair) dozens of Dell laptops, but this is my first Toshiba. Lo and behold, the CMOS battery is soldered to the motherboard. Do I either have to unsolder it and resolder a new one, or get a new motherboard?

(Google seems quite proud of itself for finding results that match 4 out my 5 search terms, just not the critical one - M55)

posted by mysterious1der to computers & internet (5 answers total)

This seems to me like something that might be solved more easily with software, assuming by "won't keep time" you mean it's somewhat fast or slow. I know you can set the basic Windows clock to readjust itself to time via the internet - you might consider investigating a way to just have the clock check the time online at more frequent intervals. This might require some tweaking or a separate program, I'm not really sure, and of course it won't solve the problem if the clock is radically off so that as soon as it readjusts it's bad again...nor will it help much if the laptop spends significant amounts of time offline. Before you go messing with the CMOS battery and playing with solder, though, you might consider a little research into some software-forced adjustment instead.
posted by Rallon at 8:24 AM on December 9, 2007

What OS is it running? There are various time synchronization options at your disposal if this computer is able to get on the internet or able to talk to another computer on the lan that has correct time.

You can also change the interval to daily or every 12 hours or whatever you like. Heres how in windows xp.
posted by damn dirty ape at 9:14 AM on December 9, 2007

I agree with Rallon. If that won't work though, for whatever reason...the CMOS battery is pretty quick and easy to replace if you've soldered before. This is not, however, the place to learn soldering.

The other thing to check is if there is an integrated clock/battery on-board - - Dallas Semiconductor makes the most common ones. If you see a Dallas chip on board, replacing the CMOS battery won't help you.

Back to the software thing: if you run Windows XP, open up Regedit and stick w32tm /resync /rediscover in HKLM\Software\Microsoft\Windows\CurrentVersion\Run - - that will force it to synchronize on boot.
posted by rpaxton at 9:20 AM on December 9, 2007

What is the time difference on an average day? Does it run too slow, or too fast?

I use AboutTime as a startup application on an old Toshiba with a too slow running clock. It shuts itself down after the internal time is corrected.
posted by ijsbrand at 9:22 AM on December 9, 2007

I have the same problem, different laptop though (compaq presario 2267AP - windows XP SP2). I opened it up but couldn't even find a battery. The only other option i could find was to reinstall the bios throught he hp/compaq support website (I don't know heaps about computers but apparently some CMOS settings are run from flash memory or something Hopefully sopmeone will set me straight if i'm wrong. ) but after multiple tries to download the update the connection keeps timing out. I'm not a computer guru, so I don't really know what I'm doing anyway. perhaps you can find some help at the toshiba support pages?

I just update the time manually whenever I need it to auto update my anti-virus.
posted by robotot at 1:38 PM on December 9, 2007