t42 not recharging battery after spill

[lynnja]

I spilled water on my T42 a while ago and it is working again. the only problem I had was that the battery seemed to be fried, so I bought a new one. While I can run the computer on the battery without the adapter, it does not recharge the battery when I plug it back in. Is this something that can be easily fixed?

Thanks,

[rkawakami]

If the water damage caused a part (or parts) on the motherboard to short out, then there's really no "easy" fix unless you are adept at working on electronic equipment and have the tools needed to test and replace those components. That's assuming you are talking about a component-level repair. A fuse could have blown or the battery charging controller IC may have been fried. You would have to identify if any of the components are damaged and then source their replacement(s).

There may also be some contamination left on the board, which if cleaned up, could restore your system to proper operation. Cleaning up any white powdery residue with isopropyl (rubbing) alcohol and a cotton swab might help. Some people have even recovered from a liquid spill by soaking the entire motherboard in an alcohol bath but I'd recommend only a selective area cleaning for now. In either case, allow the board to thoroughly dry before applying power.

The "easiest" way to fix the problem would be to replace the entire motherboard with a known good unit. However, this also has some risks since we are talking about a T4x system, which if it uses the ATI graphics processor, has some history of working loose from the motherboard and causing video and/or power-related problems.

[poshgeordie]

Adding to Ray's comments - have a look at my T4x Fuses Diagram and check F9 and F12.
F12 (10 Amps) will be the main battery supply fuse and I will probably need to be OK for both charging and running on battery.
The purpose of F9 (0.5 Amps) is less clear but will probably control a chip in the charging circuit chain somewhere.

If they are both OK, have a look at this very useful post which shows the components to check in the battery charger circuit.

This circuit diagram made by SMA is V useful in showing the major components used in the charging circuit.

The location of the ADP3806 chip referred to can be seen on my diagram.
Refer to the first one; the 24 pin chip is upright and to the left of "F7" logo, and just to the left of the elliptical hole under the logo.
The top of the chip is at 5 O'clock position from the top circular metal standoff on which the modem / bluetooth daughterboard is mounted.

It seems that a number of people have had success in tracing the fault through this post.

<Edit to add chip details

[lynnja]

Great info. Thanks Nick and Ray!

[laboye]

Hi. Did this fuse problem cause the ThinkPad to only power on if a battery is present? My T42 won't work with AC Power alone but works fine with only a battery or both. I have not tested to see if the battery charges or not, though. I'll update that info in my thread, which is here:

http://forum.thinkpads.com/viewtopic.php?f=2&t=76714

Thanks,

-Eddie

[lynnja]

No, mine doesnt need the battery in to power on. The battery has zero charge and I had it out and it only need the power adapter to turn on. It can run off a charged battery without the AC adapter also. but will not recharge a battery.