Author Topic: Help Testing a Laptop PSU IC  (Read 7512 times)

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Offline CalebHansberry

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Help Testing a Laptop PSU IC
« on: November 15, 2014, 07:05:07 pm »
Hello, I really need help testing a laptop power supply. The laptop is a Lenovo IBM ThinkPad T60p, and what I believe is the PSU (can't be totally sure as I don't have a schematic which costs money) is a Toshiba TPC8109. The datasheet can be seen here: http://pdf.datasheetcatalog.com/datasheet/toshiba/2849.pdf

I have a multimeter and a/c adapter, and similar tool, if I need to test resistance, or do anything about running voltage through it, I dunno? Never tried anything like this before, but I really need to get this IC tested.


EDIT: It's significant to note that when running, this laptop states the battery level as being 99%, but it obviously will under no circumstances run without the charger; the battery isn't really at 99. Butt assorted battery programs say it is, which could be a good clue! Also, in BatteryMonitor, a good deal of information is "not available", like Charge Rate and Charge Cycles.
« Last Edit: November 17, 2014, 03:07:22 pm by CalebHansberry »
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Offline Vogtinator

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Re: Help Testing a Laptop PSU IC
« Reply #1 on: November 16, 2014, 07:54:37 am »
The "PSU" you linked to is just a MOSFET, no logic.
I'd assume that the battery (probably its controller) is broken.

Offline CalebHansberry

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Re: Help Testing a Laptop PSU IC
« Reply #2 on: November 17, 2014, 03:07:00 pm »
Haha, thanks for that much info at least, I wouldn't tell them apart. And very few people I know could either...
I don't think the battery is harmed, as I bought it on eBay working from a good seller... but I can't be 100% certain. Perhaps 80%.
Do you know of a way I can test to see if anything is wrong with the battery? I really gotta test either the motherboard or the battery *somehow*, or else I'd buy a new battery to see, and it'd not work, then I'd buy a new motherboard, and I don't have that much money for that. Surely there's a way to know which is at fault?
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Offline Vogtinator

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Re: Help Testing a Laptop PSU IC
« Reply #3 on: November 17, 2014, 03:10:48 pm »
It's most likely a proprietary protocol that's used to communicate between PSU and battery. Without this communication, the battery will not load or give much power.
You can try to measure battery voltage while it's plugged in. Some laptops also have some settings in its BIOS.

Offline CalebHansberry

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Re: Help Testing a Laptop PSU IC
« Reply #4 on: November 17, 2014, 11:49:12 pm »
Hmm, I'll try. If you have any suggestions as to how to try to measure the battery voltage that'd be fine, though I'll certainly try to do my own research. Will I accidentally blow up the battery if I somehow short it? (well prolly not since it prolly has no power) And if I succeeded in doing this - would that test the motherboard's ability to send power, or the battery?
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Offline Vogtinator

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Re: Help Testing a Laptop PSU IC
« Reply #5 on: November 18, 2014, 04:00:36 am »
Hmm, I'll try. If you have any suggestions as to how to try to measure the battery voltage that'd be fine, though I'll certainly try to do my own research. Will I accidentally blow up the battery if I somehow short it? (well prolly not since it prolly has no power)
It could have enough voltage to spark, so be careful.

Quote
And if I succeeded in doing this - would that test the motherboard's ability to send power, or the battery?
Just try to find the battery contacts for + and -. You can always test from which side the voltage is coming from using a diode.

Offline CalebHansberry

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Re: Help Testing a Laptop PSU IC
« Reply #6 on: January 29, 2015, 11:44:03 pm »
Hi, sorry I'm posting so late.

I measured + and -, and here's what I got: 9v sometimes when it's plugged in, but often 0v. Unplugged there was a chance it'd read 0.01V but prolly nothing. So, does this information help in determining whether the laptop or the battery is at fault?
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Offline Vogtinator

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Re: Help Testing a Laptop PSU IC
« Reply #7 on: January 30, 2015, 01:14:36 am »
It doesn't help much, a laptop's power circuit is a complex piece. Did you measure the supply while it's not plugged in?

Offline CalebHansberry

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Re: Help Testing a Laptop PSU IC
« Reply #8 on: January 31, 2015, 02:35:20 pm »
Could you rephrase what you mean? I did measure the pins on the laptop heading to the battery while the battery wasn't plugged in, which yielded 0V generally
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Offline Vogtinator

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Re: Help Testing a Laptop PSU IC
« Reply #9 on: January 31, 2015, 02:38:46 pm »
Well, the laptop won't try to charge a battery if there's no battery plugged in.
If you get 9V if the battery is plugged in, it's certainly broken. It's by far not enough (and not a multiple of 3.7V).
Is there voltage if the laptop tries to charge?

Offline CalebHansberry

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Re: Help Testing a Laptop PSU IC
« Reply #10 on: January 31, 2015, 02:41:35 pm »
If the laptop tries to charge? That'd be the 9v, right?

EDIT: Project abandoned due to my realization that I'm in far over my head with something like this. It'd be better for an EE, not a basic computer repair guy. As I'm trying to make money refurbishing, I'll simply need to sell it as-is: it's not worth the risk of buying a new battery, in case the issue is the motherboard.
« Last Edit: January 31, 2015, 06:22:31 pm by CalebHansberry »
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