CMOS Battery PSA - mid 90s-early 2000s laptops affected!

3lectr1c

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May 15, 2022
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Anyone who has dealt with enough vintage macs knows of the horrors a battery leak can cause. Unfortunately, a whole new generation of vintage tech is now being affected in mass by this - laptops from the mid 90s-early 2000s.

The TLDR is that many laptops from many brands at the time used multi-cell NiMH rechargeable CMOS batteries manufactured by VARTA (yep, them again). These batteries are beginning to leak, really bad. They can range from 1-6 cells, and various capacities, but they will all leak.

Brands that I know used them: Apple, Dell, Toshiba, IBM, Sony/VAIO, and likely many others! There were a ton of now very-obscure manufacturers that are now long-defunct, many of which may have used these.

Apples specifically that have these: PowerBook 150, 2400, 3400.

I've personally ran into 4 of them myself, and all have been leaking to some degree.

1 - Dell Latitude CPi D300XT: Just beginning to leak, corrosion made its way down the connector.
2 - Dell Latitude CS 400XT: Leaking bad. Damage to the motherboard and keyboard. Motherboard was still working, but with minor IDE issues and inconsistent booting. Keyboard had multiple dead keys due to corrosion.
3 - Dell Latitude C610: Had been removed many years ago, upon checking up on it it had begun to leak. Another C610 I got for parts had no battery but corrosion on the battery connector pins, evidence of a previous minor leak.
4 - Apple PowerBook 3400c/200: Just beginning to leak, corrosion on the connector like before.

Many may have run into one of these before, realized it was leaking and removed it, but not known just how wide-spread these were in laptops of the time. Just about every Dell from the time had them, same with Toshiba, IBM used them in a few models, and I just learned of Sony's use of them today! This proves that if you've got any laptop from this time period, you need to check them to verify that they don't have these batteries, and remove them if they do. The time is now people! I've seen so many recent YouTube videos of people demoing these laptops working still with no knowledge of the time-bomb inside them. This is far worse than the Lithium batteries in old Macs, where you can still find plenty that haven't been damaged yet. I'd have to guess that after only 20 years, 90%+ of them have at least started to leak, and by the time they hit 30 years old, just about every laptop that used them will be damaged beyond repair.

Save your laptop before it's too late!!!
 

3lectr1c

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You can add Compaq and Texas Instruments laptops to the list. Found that compaq laptops used them myself and a guy on another forum said TI used them too. That just about covers every major brand…
 

Stinkerton18

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Aug 18, 2022
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I had a PB3400 who's power distribution board was ruined because of this. The leaking electrolytic from the batteries wicked right up and through the connecting wire. The laptops I've picked up since that's the first thing I do, yank the CMOS battery.
 

3lectr1c

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And yet, it still managed to do that to your unit, even though the battery is located on the whole other side of the computer on such long wires. Truly nasty stuff.

One thing I can safely say at this point is that just about every single laptop manufacturer used these at some point. Every one, with barely a single exception. Not every laptop did, but just about every brand did, at some point. If you have ANY vintage laptop, just check. Take it apart. It's not worth taking the chance.
 

mmu_man

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Jan 30, 2022
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Indeed I noticed the VAIO PCG-F707 I just got didn't only have the rubber feet that leaked, but also the CMOS battery that's well hidden inside the very front of the case, not even under the keyboard or some accessible place. I'll have to open it all to remote it…
 

3lectr1c

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May 15, 2022
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get 'er out!

I've pulled two vartas in the past week - one out of a Samsung SENS 800, and another out of a ThinkPad 770ED. Both leaking (of course), neither damaged much. 770ED's connector sustained some damage, SENS 800's didn't. Both survived.