Lenovo YOGA 2 13 (20344) hot cpu when plugging

[Garibean]

Hi

I'm a beginner in laptop repair, a friend of mine gave me his laptop to repair, a Lenovo Yoga 2 13 (20344), he said that when he plug the laptop, he hears a buzzing noise.
I checked, this is a coil next to the cpu. When plugging the laptop, the cpu start getting hot and the coil next to it too and that without even touching the power button.
My guess is that the cpu is simply fried and he can now toss it in the bin.
(I also could not find schematic for this laptop so i will create a thread about it)

Do you have any idea about what it can be ?

Thx

[Stevedb]

Re: Lenovo YOGA 2 13 (20344) hot cpu when plugging

Probably is the pch the smaller die on the cpu

[Garibean]

Re: Lenovo YOGA 2 13 (20344) hot cpu when plugging

I forgot to say one thing, he tried to plug the laptop charger on a usb 3.0 port. I don't know he was maybe angry or something but he managed to destroy the usb port and plug the laptop charger inside it... maybe the 19.5v went throught the connector and fried everything in his pace ? (the cpu is directly connected to usb ?)

[Vesko356]

Re: Lenovo YOGA 2 13 (20344) hot cpu when plugging

I also could not find schematic for this laptop so i will create a thread about it

Search harder: https://www.badcaps.net/forum/showth...058#post874058

Measure resistance to ground in +3VALW line, if it's low means 99% dead PCH or if you're lucky only shorted EC.

.

[Garibean]

Re: Lenovo YOGA 2 13 (20344) hot cpu when plugging

My bad :/
I will test it this afternoon, thank you

[Garibean]

Re: Lenovo YOGA 2 13 (20344) hot cpu when plugging

Search harder: https://www.badcaps.net/forum/showth...058#post874058

Measure resistance to ground in +3VALW line, if it's low means 99% dead PCH or if you're lucky only shorted EC.

.

So i tested between +3valw, +3valw_pch and GND and i have 0 ohm...
When you say EC, you speak about the EC reset ? I have 85k between +3valw_ec and GND, so that means it's only the pch ?...

[Vesko356]

Re: Lenovo YOGA 2 13 (20344) hot cpu when plugging

So i tested between +3valw, +3valw_pch and GND and i have 0 ohm...
When you say EC, you speak about the EC reset ? I have 85k between +3valw_ec and GND, so that means it's only the pch ?...

EC=Embedded Controller, it's a chip - ENE KB9012 according to the schematic in your case.
Disconnect PJ401 (remove the solder) and measure the resistance to GND at both sides of the jumper pads.

.

[Sephir0th]

Re: Lenovo YOGA 2 13 (20344) hot cpu when plugging

There are almost no doubts you're dealing with a fully shorted PCH here, as already clarified two times. It's one of the most common issues.

[Garibean]

Re: Lenovo YOGA 2 13 (20344) hot cpu when plugging

EC=Embedded Controller, it's a chip - ENE KB9012 according to the schematic in your case.
Disconnect PJ401 (remove the solder) and measure the resistance to GND at both sides of the jumper pads.

.

Hello !

So little update, i disconnected pj401 and verified continuity between both sides to be sure that it's correctly disconnected
Then i tested +3valw to gnd and i got 0.1-0.3 ohm and a growing 17k on +3valwp. So as many of you stated, the pch is dead and i will use this board as spare parts !

Thank you for your help, i already like this community, i bought a microscope, a hot air station and a thermal camera to repair every thing (mostly stuff from friends and family). I think i will have a lot of fun