Dead ASUS ROG G14 (GA401)

[jacobtc]

Hi!

It seems like all the laptops I get are dead G14's. I already had two, in which one was fixable, and one wasn't. This one is different though, I promise!

The previous owner used it without a screen, as the panel was dead, and suddenly it just died.

The board looks fine, no visually burnt components as I can see.
I do not get a short on the DC-In mosfets, however as I had with one of my other machines, the first mosfet does not seem to let voltage through, so the second mosfet does not receive 20V. (See pic).

Only the BQ chip gets a little warm when the board is plugged in, nothing else.

I believe I detect a short around the caps at the bios chip (1 Ohm), not sure if they should be that low. I removed the bios chip, but reading is still as low.

Caps at GPU area are 22 Ohm, so they are probably not short.

All Mosfets measure in the K or MOhm range, except one, which is 200 Ohm at D-S, so not really sure what is going on there.

I would have hoped that a completely dead PC would mean an obvious short somewhere, but nope

The other G14 I had, had sign of life with USB-C charging, but this one seems dead.

[jacobtc]

Re: Dead ASUS ROG G14 (GA401)

I injected 1V1A into the cap on the right of the bios chip which were 1 Ohm. The IT5125VG-128 IC on the back side got hot, could this be the culprit?

[reformatt]

Re: Dead ASUS ROG G14 (GA401)

No schematics or boardviews I think for this model. But yes looks like a failed EC.

To confirm, I'd look for the +3.3V regulator IC on this board, find it's type and refer to the datasheet. Look for the +3V LDO pin on that, and check resistance to ground.

[jacobtc]

Re: Dead ASUS ROG G14 (GA401)

No schematics or boardviews I think for this model. But yes looks like a failed EC.

To confirm, I'd look for the +3.3V regulator IC on this board, find it's type and refer to the datasheet. Look for the +3V LDO pin on that, and check resistance to ground.

There is a schematic and boardview here: https://drive.google.com/file/d/1hMZ...uyI_3v7nK/view

I will check for the regulator when I get home from work, if I can find it.

[jacobtc]

Re: Dead ASUS ROG G14 (GA401)

I found this in the schematic, not sure if this is the 3V3 though. Having a hard time finding what makes 3V3...

Im new

EDIT: Also, some caps are very low resistance right above the lower mosfets.

[jacobtc]

Re: Dead ASUS ROG G14 (GA401)

Should I remove the ITE EC and check if the short is gone? I will have to reball it again, if the short is still present though

[reformatt]

Re: Dead ASUS ROG G14 (GA401)

It's a convoluted design compared to most other laptops and I'm still scratching my head a little following what should be a simple path for powering the EC.

+3VAO/+3VA (pin 3 of PU8701) is your LDO voltage. However +3VA_EC goes via load switch (PU8801) so if it's shorted it might read it on the other side of that load switch. So check resistance to ground for +3VA and +3VA_EC. Pg 101 has the power sequence diagram for further troubleshooting.

[jacobtc]

Re: Dead ASUS ROG G14 (GA401)

It's a convoluted design compared to most other laptops and I'm still scratching my head a little following what should be a simple path for powering the EC.

+3VAO/+3VA (pin 3 of PU8701) is your LDO voltage. However +3VA_EC goes via load switch (PU8801) so if it's shorted it might read it on the other side of that load switch. So check resistance to ground for +3VA and +3VA_EC. Pg 101 has the power sequence diagram for further troubleshooting.

Thanks for you support! Yeah, the schematics are not easy to figure out.

I checked both Pin 3 on PU8701, it was 4.6 MOhm to ground.
I checked VOUT1_1 (Pin 13) on PU8801, and it was 1 Ohm to ground.

How would I use the power sequence diagram? I guess it is for knowing the starting sequence of the components at boot, but how would that help me?

Thanks!

[reformatt]

Re: Dead ASUS ROG G14 (GA401)

Based on your previous post, that does sound like a shorted EC (U3001). You can use 1V voltage injection and thermal camera to confirm. Removing U3001 would be the next step to see if the short is gone.

No datasheets available for IT5125VG-128/CX, however the 128 suggests that it has 128k of ROM. Some EC's when empty download their code from the main BIOS chip automatically. Given I can't see any EC dumps on the web for this model seems to indicate that this is likely the case.

[jacobtc]

Re: Dead ASUS ROG G14 (GA401)

Based on your previous post, that does sound like a shorted EC (U3001). You can use 1V voltage injection and thermal camera to confirm. Removing U3001 would be the next step to see if the short is gone.

No datasheets available for IT5125VG-128/CX, however the 128 suggests that it has 128k of ROM. Some EC's when empty download their code from the main BIOS chip automatically. Given I can't see any EC dumps on the web for this model seems to indicate that this is likely the case.

I injected voltage here (see pic).

How often do EC's die though? I am fearing that it is something else that is shorting the EC.

Yes, as I have reseached, especially Asus downloads to EC from BIOS at boot.

[reformatt]

Re: Dead ASUS ROG G14 (GA401)

They do go short. As to why who knows. Often it's because of some external event. Some Lenovo's have a direct connection to the power jack for adaptor sense. When the power jack disintegrates, you get 19V on a pin that should only take 3V and this destroys the EC.

But this is not the case in this instance. Asus laptops often have failures that many other brands do not. Have a look at Northridge Fix's channel and he always goes on about how shit Asus laptops are.

[jacobtc]

Re: Dead ASUS ROG G14 (GA401)

Alright, I'll remove it and see if the short disappears 😅

[jacobtc]

Re: Dead ASUS ROG G14 (GA401)

Also, IF I need to reball, how do I know what ball size to use, without a datasheet for the ITE IC available?

EDIT: I might go with solder paste and one of my universal stencils...

[rediii]

Re: Dead ASUS ROG G14 (GA401)

Also, IF I need to reball, how do I know what ball size to use, without a datasheet for the ITE IC available?

EDIT: I might go with solder paste and one of my universal stencils...

if you want to use solder balls, just go to aliexpress and search for the ite chip model and a proper stencil. look on the pictures that will tell you the ball size. otherwise try universal stencils that will match in size.

[jacobtc]

Re: Dead ASUS ROG G14 (GA401)

They do go short. As to why who knows. Often it's because of some external event. Some Lenovo's have a direct connection to the power jack for adaptor sense. When the power jack disintegrates, you get 19V on a pin that should only take 3V and this destroys the EC.

But this is not the case in this instance. Asus laptops often have failures that many other brands do not. Have a look at Northridge Fix's channel and he always goes on about how shit Asus laptops are.

Removed the EC, and the cap that previously measured 1 Ohm, now measures 10 kOhm!

Is it safe to say that the EC was at fault? The EC is 20USD from Aliexpress, so I want to be somewhat safe before ordering one

Also, I guess that I should not connect power to the board without the EC, correct?

Thanks for your help!

[jacobtc]

Re: Dead ASUS ROG G14 (GA401)

if you want to use solder balls, just go to aliexpress and search for the ite chip model and a proper stencil. look on the pictures that will tell you the ball size. otherwise try universal stencils that will match in size.

Yeah, I found a stencil that works, I might buy that if for some reason I have to reball a new EC IC.

[rediii]

Re: Dead ASUS ROG G14 (GA401)

Removed the EC, and the cap that previously measured 1 Ohm, now measures 10 kOhm!

Is it safe to say that the EC was at fault? The EC is 20USD from Aliexpress, so I want to be somewhat safe before ordering one

Also, I guess that I should not connect power to the board without the EC, correct?

Thanks for your help!

yes, then it was at least ONE fault. there could be more. nice job . mostly it is not safe to connect power to a board without controller ics... but in most cases the board will be just brain dead and that's it.

[reformatt]

Re: Dead ASUS ROG G14 (GA401)

Yes EC is shorted, replacement should theoretically come pre-balled. I personally wouldn't power the board without it fitted.

Replacement needs to be blank or off a donor board (of the same model) as well. I ran into some issues transplanting an EC with different programming once. I didn't have a 128 pin ZIF adaptor and thought I could reprogram it via the keyboard connector. Well it didn't end well and I won't be doing that again. To date, I've not seen any programming adaptor for the 128 pin BGA EC's.

[jacobtc]

Re: Dead ASUS ROG G14 (GA401)

Yes EC is shorted, replacement should theoretically come pre-balled. I personally wouldn't power the board without it fitted.

Replacement needs to be blank or off a donor board (of the same model) as well. I ran into some issues transplanting an EC with different programming once. I didn't have a 128 pin ZIF adaptor and thought I could reprogram it via the keyboard connector. Well it didn't end well and I won't be doing that again. To date, I've not seen any programming adaptor for the 128 pin BGA EC's.

Yeah, I will buy the part from SUHMS on AliExpress, so it should be all good!

Hope it won’t die instantly due to some other fault on the board

[jacobtc]

Re: Dead ASUS ROG G14 (GA401)

yes, then it was at least ONE fault. there could be more. nice job . mostly it is not safe to connect power to a board without controller ics... but in most cases the board will be just brain dead and that's it.

Yeah, what worries me is if something else causes the EC to die, that would be 20 USD wasted if the new chip just dies instantly