Asus G751JY laptop doesn't turn on anymore, makes high-pitched sound when charger is plugged in.

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May 30, 2018
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Hello. I have an Asus ROG G751JY, Windows 8.1, with the battery removed .
As I hadn't ever cleaned it, I decided to do it. While at it, I went all the way and also replaced the fans with new ones and also repasted with Thermal Grizzly Conductonaut (liquid metal). I followed the procedure very carefully, left no bubbles at all and also protected the area around the cpu and gpu with Scotch super 33+ tape, so that in the unlikely event of the liquid metal sliding somewhere, it wouldn't touch anything dangerous.
I'm saying all this because I would like to look for a solution excluding a mistake in liquid metal application.

SO here's what happened. After I finished with everything, I wanted to see if the new GPU fan was working (because they gave me a defective one at first). So I didn't put the keyboard back, and just turned on the laptop. Everything fine! It turned on and went straight to BIOS. Unfortunately this didn't give me a chance to test the fan, so I decided to also plug in the ssd, in order to boot into windows and do something that would make the fan spin. So I turned the laptop around.

This is where I think something went wrong. While turning it around, I heard a little noise (not the high pitched continuous sound I will describe later), like something was inside the case. I thought maybe I didn't screw something in well, or that maybe I dropped something (anything) and didn't notice it. I turned the laptop around and moved it a bit in order to get it to come out. I couldn't pinpoint where it was, but the noise stopped. I thought that I got it to come out and that I just didn't hear it fall on the floor.
So I continued, plugged the ssd in, plugged the mouse and the charger.

And this is when the continuous high pitched sound started, right when I plugged the charger in. I tried to turn the laptop on, but it didn't (and doesn't since then). The sound only comes up when I plug the charger in, otherwise it stops. In an effort to see if a connection came loose and maybe that was causing the problem, I again disassembled the laptop, leaving only the motherboard and the heat pipes there ( I even removed the little board that houses the power button). I plugged the charger then and the high-pitched sound was still there. Although it is kinda difficult to pinpoint where exactly the sound is coming from, I think it is coming from a spot in the motherboard where the little circular battery is taped in (the underside of which has a chip that looks like a small cpu), and also from the spot where the charger connects to the motherboard.

At this point I really don't know what to do. Everything was almost finished, the laptop turned on and then this occured at the last moment and I don't want to believe I damaged it just from moving it around a bit. Please help me, this is my personal laptop and I doubt I will ever have the money to spend on such powerful hardware again.

HTB10F0zvKuSBuNjSsziq6zq8pXag.jpg

See where the big cut for the fan is? The sound comes from right under it, and from its right side (where the charger connector is)

EDIT: I can confirm the sound comes from the kinda big-sized (shiny in the picture, due to tape?) chip under the cut for the fan. The chip is called SR17D if i got it correctly.
 

shmoochie

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May 10, 2018
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Pretty sure that chip is the DMI which is the link between the northbridge and southbridge.

Maybe something got scrambled in the CMOS when you booted it with a new fan installed? Although, I'm not exactly sure why that would make a high pitched noise. You could reset it just to try.

It honestly sounds like something is damaged to me. If you heard something rattling inside and then it suddenly started doing this, then I would say there is a good chance that is the culprit. You could try contacting the manufacturers, but applying the conductonaut most likely voided whatever warranty you might have. They will probably claim it was a user error. When you try to boot it, does it act like it is doing anything at all? (Screen flashes, beeps, power cycling)
 
May 30, 2018
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No, nothing happens when I try to turn it on.
How and what should I try to reset? I'm pretty desperate, whatever I can try, I will.
 

shmoochie

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You want to reset the CMOS, which holds hardware and BIOS information. Usually you can do it on laptop by removing the battery and charger and holding down the power button for ~30 seconds. You can also unplug the CMOS batter for about 30 seconds. Here's a pic:
 
May 30, 2018
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Unfortunately, I 've tried the first method and it didn't work.
I also tried the second method unknowingly. I removed the CMOS battery to see if the sound would still be there without it and yes, it was still there when I plugged my charger in. And I believe this procedure took me more than 30 seconds. (also thank you for taking the time to help me!)
 

shmoochie

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Sorry, so that is actually the platform controller hub which controls some northbridge functions and all the southbridge and I/O functions. Coil whine is not uncommon, but the fact that the coil whine started after you heard something rattling in the case (and also the fact that the computer won't start anymore) makes me think that the pch is damaged. You could buy a replacement and solder it on if you have the expertise, but otherwise you might look for a mobo replacement. Even if your laptop was under warranty, applying the conductonaut probably voided it as the manufacturers would just claim that the damage resulted from user error.

Edit: Maybe someone else will come along with some better advice, but that is all that I can think of.
 
May 30, 2018
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I 'm just wondering what or how something came off, to make that rattling sound. Took me hours to do it, just because I was super careful. At least I learned what the so called coil whine is (always nice to learn something new).

I will go to a parts/service store I kinda trust on Monday, to see if they can help me with soldering a new one.
You have been really helpful, thank you very much. I'll just postpone marking the thread as solved for a bit, to see if something comes up before Monday. Again, thanks a lot.

EDIT: My warranty was voided 3 years ago anyway.
 
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