T-42 AC Power to Battery Power Issue

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Deleau · #1 Post by **Deleau** » Fri May 11, 2007 11:29 am

Recently an interesting (really, troubling) issue has arose. My T-42 will only run in AC power. Whenever I unplug the AC power, the laptop shuts off. While the AC is not connected there is no battery light or anything.

Here's what is crazy...while on AC power, the battery shows up as being there, it has a charge; I can even 'condition' the battery (it is actually charging up right now as I type this). The battery is a few years old, and it is getting run down (I get less than an hour on a charge now...14.26 Wh full charge now, 47.52 Wh design, 272 cycle count), but it has always been able to switch over to battery.

Any ideas?

Thanks

#2 Post by **rkawakami** » Fri May 11, 2007 11:42 am

Two possible issues that I can see:

- weak/dead/defective battery
- power circuit problem on your motherboard

Suggest you obtain a different battery and see what it does with that one. If you get the identical "performance" out of the replacement battery, then I'd say you have a motherboard power problem. If the replacement battery functions normally, then your existing battery is defective.

You could also try your battery in another T4x system and see what happens there.

QLi · #3 Post by **QLi** » Fri May 11, 2007 11:47 am

Is there a fix if it's a power circuit problem or is a replacement board needed?

#4 Post by **rkawakami** » Fri May 11, 2007 11:55 am

"Easiest" fix is to replace the motherboard, if that's what the troubleshooting points to. Only if you have the electronics knowledge and proper equipment, does a component-level repair make sense. As the schematics are not available (to my knowledge) you would be "looking" for an obvious problem (burnt or loose part) or using a meter to test a few simple things (blown fuse, open connection). If you did manage to isolate the problem to a single component, you then have the problem of identifying what it is and where to get a replacement.

#5 Post by **richk** » Fri May 11, 2007 2:21 pm

I recently worked on a mothboard that had similar symptoms. When I finally gave up and pulled it out, I found evidence of a spill near the power jack. I played with it for too long (resoldering chips near the spill) before I threw it away.

Deleau · #6 Post by **Deleau** » Fri May 11, 2007 2:21 pm

Thanks. I certainly hope it is not an issue with replacing the MB...

Regardless, I've got a couple additional questions:

1.) What and where is the best place to get a replacement battery? (Sorry, if there are other posts; I will search later but any guidance is appreciated)

2.) Likewise, where is the best place to get a replacement motherboard (besides Lenovo)?

3.) Is there any way to test further whether it is a battery or circuit issue prior to getting a new battery?

Thanks again.

#7 Post by **richk** » Fri May 11, 2007 3:15 pm

The VERY best way to get a new battery is to borrow one from someone with a compatible machine. Any T40/r1/42/43 or R50/51/52 is OK. After that, you can get a used battery on eBay, but sometimes they don't work. It is generally OK if you buy from someone with good feedback. A local computer repair shop might have one you can try there, but sometimes they want some sort of fee to diagnose your problem.

The question on where to get a MB depends on whether you want to fix it yourself. You can get a used board on eBay. They are usually good, but sometimes there are problems. T40, 41 and 42 boards will all work in your machine, but you will lose features or speed if you go to a board from an older machine. I sell T40 boards and tell buyers the differences, but some sellers say they are all the same. What is the model number of yout machine? It can come from a sticker on the bottom, something like 2373-xxx. It can also be seen if you boot into the BIOS.

Deleau · #8 Post by **Deleau** » Fri May 11, 2007 5:11 pm

Well, regardless the battery is old enough and even after running the recondition tool, the full charge capacity is in the 14 range which is not much anyway, so I do not mind buying a quality replacement. Is buying a replacement from Lenovo the best way to go there or are there other places and/or brands that are better for a replacement?

Edit: I have T42 2378-FVU

#9 Post by **richk** » Fri May 11, 2007 6:05 pm

I would look for a new one online - cheaper than Lenovo. The battery might fix your problem, but the MB is as least as likely. If your MB is bad, are you sure you're going to fix it? If you decide the cost is too great, buying a new battery now is just an extra expense.

Deleau · #10 Post by **Deleau** » Fri May 11, 2007 8:01 pm

Well, within the last year I've upgraded the RAM to 2GB and upgraded the HDD to 100GB 7200RPM, so I'd rather not have to toss it away just yet. I've been eyeing a new T60 as it is, but I'd like to keep this one around for a while still.

T-42 AC Power to Battery Power Issue

T-42 AC Power to Battery Power Issue

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