UX31e loading problem?

[Beatz01]

Hi,

I have a Asus UX31e and when I put the charger in it it does not load. It does see that the charger is in but not loading. Also, there is a new battery in it wich works.

So this made me believe that a chip (charging chip?) is faulty but I don't know which one it is. So I have schematics but I can't understand it. I will put these schematics up and hope someone can help me with this problem.

Greetz,

B3atz

[mielta]

Re: UX31e loading problem?

Hi
Its Page 88 chip is PU8800 you must messure all voltages only with battery and then
battery + charger

[BlueMidnight]

Re: UX31e loading problem?

The schematic is for a different board. I think the real schematic isn't available. That's why sites give/sell that one instead. It is very similar. But it has a lot of differences too. For example, the board in the schematic uses a completely different charging chip with fewer pins.

The charger IC on your actual board is a 28-pin Texas Instruments BQ24740.


Some questions:

What revision is your board? (e.g. "Rev. 3.0")

When you say "does not load" do you mean the battery does not charge? or do you mean the computer does not start up?

What happens if only the battery is connected? What if only the AC adapter is connected?

Measure the voltages on all pins of BATFET and the charger IC. Do it with the board turned off, and connect both the battery and the AC adapter. It may be helpful if you repeat the measurements with just the battery connected, like mielta said. Forum replies take time. It's better to measure too much than to measure too little.

If the computer won't start up, then measure ACFET and RBFET also. Otherwise, don't worry about them.

Also, be very careful measuring the small pins on the charger IC. A "needle" style probe tip is recommended. Accidentally shorting two pins together with the probe can damage the board.

[Beatz01]

Re: UX31e loading problem?

The schematic is for a different board. I think the real schematic isn't available. That's why sites give/sell that one instead. It is very similar. But it has a lot of differences too. For example, the board in the schematic uses a completely different charging chip with fewer pins.

The charger IC on your actual board is a 28-pin Texas Instruments BQ24740.


Some questions:

What revision is your board? (e.g. "Rev. 3.0")

When you say "does not load" do you mean the battery does not charge? or do you mean the computer does not start up?

That was my mistake with words. I had to use the word charging instead of loading. So it's a charging problem.

What happens if only the battery is connected? What if only the AC adapter is connected?

It does work with a battery that is charged (I have 2 of the same laptops so I load the one with the other) but when you put in the charger it does not charge. You do see that it is plugged in.


Measure the voltages on all pins of BATFET and the charger IC. Do it with the board turned off, and connect both the battery and the AC adapter. It may be helpful if you repeat the measurements with just the battery connected, like mielta said. Forum replies take time. It's better to measure too much than to measure too little.

If the computer won't start up, then measure ACFET and RBFET also. Otherwise, don't worry about them.

Also, be very careful measuring the small pins on the charger IC. A "needle" style probe tip is recommended. Accidentally shorting two pins together with the probe can damage the board.

Thanks for the tips and I will try to look for the chip that is responsble for charging the laptop. Thanks!

[Beatz01]

Re: UX31e loading problem?

And these are the pictures of the board:

[BlueMidnight]

Re: UX31e loading problem?

Okay, that's good. It's very helpful to know it's a revision 3.2 board. Just let us know your measurements when you're done and we'll go from there.

It sounded like you probably meant "charge" but I just had to make sure :P