MSI GL62 7RDX not charging, not powering on

[trufla]

Hello !

First of all would like to say hello to everyone here and thank you to the creator of this forum for making such a place These days not much places where kind souls willing to share their knowledge still residue remains

Not sure where to start so i'll start from the beginning.

About a year ago it was a day like other when i got some time off from being a husban and a chance to play some pc games siping some brown ale, not wanting to waste preciouse time, wiped dust of my laptop and turned it on. Then launched astroneer and went to mine some preciouse ore, after an hour or so craving for some snacks to follow that ale squized my stomach, so left the game on and went to the kitchen to fetch myself something to snack on. After coming back ive noticed that the laptop battery started crying for some juice. Not thinking much to not to disrupt my gamining session started looking for a charger and quickly plugged it in. In a matter of minutes the (whilst plugged on) the battery went dead and the laptop turned off... So i gave it few minutes to sap to that power adapter and charge up few percent before powering it on. After good 20 minutes ive pushed the power button and the screen lit up, the windows booted up and i have even managed to log in ...
Then the laptop suddenly died ... To my surprise i wasnt able to power it on again ... Tried many "noob fixes" found on google but to no vail ... After a day or two ive gave up and ordered a new one ... Then it arrived after some time and since then im happy owner of lenovo y540 and the poor msi was gathering dust somewhere the a shelves...

About two weeks ago i was doing some cleaning and found that good ol msi (one of those that wont power on with its battery removed even though plugged in to mains)...

Maybe due to sentiment or just out of pure boredome i have decided to try bringing it back to life and here my adventure with this laptop begins

Since ive got it out and started "working" on bringing it back to life ive already did few things.

First of all ive bought a new battery and installed it. To my surprise after the battery replacement the laptop turned on and i have even managed to install os on it while trying to discharge the battery to 0 before first charge.

After the battery hited zero absolute i have plugged in its charger and waited some time before trying to turn it on.

The laptop wont turn on since, first noticed that there is no charging light lit when plugged in, so ive decided to check the charger first. It was giving nice 19.5v. But when doing so i have noticed that there is a short on its plug and there was some positive current going out from it via ground.

Ok, bought a new adapter and ditched the old one ...

Tried to plug it in and get some juice into that battery but no charging light lit and laptop refuses to power on even if left plugged in on a new charger for longer period of time.

Since then i have opened the cover and checked the pins going to the battery to be having some current flowing when adapter plugged in ( 3 pins having 4.5v each other four nothing )...

Here comes my ple for assistance as a newbie, what now ? Where to ? Maybe i have missed something ? Maybe there is some miracle solution im not aware of or maybe there is somebody in here willing to guide me through the depts of troubleshooting power delivery circuitry as thats possible cause based on my small research done prior posting here

The laptop itself is kinda old and not really worth bringing it up to any service center so i thought that turning it into a little entry to a hobby would be nice

(Just fyi, a homegrown techie with lots of time and patience willing to learn and with some skills at multimeter and basics of soldering, but never attempted some sort of advanced laptop hardware repair before)

Chears!

[mcplslg123]

Re: MSI GL62 7RDX not charging, not powering on

You need to open up the mb from laptop and check for any liquid spill,corrosion etc. Then measure voltage on first 2 dc-in mosfets on pin1/4/8 and report back. take measurements with only adapter connected, no battery.

[trufla]

Re: MSI GL62 7RDX not charging, not powering on

Hello ! Thank you for prompt response ! Ok so i have the mobo opened and no there was no liquid spillage on it and no signs of corrosion/rust on any of the components inside. Seems like the mosfets are on the other side of the board will try removing it and measuring the voltage on them soon.

[trufla]

Re: MSI GL62 7RDX not charging, not powering on

https://ibb.co/4MfCHJB
Ok so i went ahead and tried to follow as instructed, pretty hard to figure out which one is which because the of the board color hard to follow tracks.

So ... If im correct the one marked on the photo attached should be the first mosfet and the readings on its pins are as follow:
1. 19.7
4. 10.4
8. 18.3

Trying to figure out which one is the secondary, will post.results shortly.

[trufla]

Re: MSI GL62 7RDX not charging, not powering on

If im correct the secondary mosfet is the one thats next to the 1st one. So the readings from it are as follows:
Pins no:
1. 3.7
4. 0.2
8. 0.2

[trufla]

Re: MSI GL62 7RDX not charging, not powering on

There is one more mosfet next to them followed by two chokes and the readings on its pins are :
1. 0.4
4. 0.1
8. 0.0

[trufla]

Re: MSI GL62 7RDX not charging, not powering on

All of the above of course if im checking them correctly that is. Check pin 1 -> plus to ground minus to pin 1. Pin 4 -> plus to pin 1 minus to pin 4. Pin 8-> plus to pin 1 minus to pin 8.

[trufla]

Re: MSI GL62 7RDX not charging, not powering on

Also not sure if its very visible on the photo provided but seems like the first mosfet looks a little bit defferently from the other two nearby (almost like browned a bit).

[mcplslg123]

Re: MSI GL62 7RDX not charging, not powering on

Yes you have correctly identified the dc-in mosfets. Put black proble to GND and then red probe to pin1/pin4/pin8 and measure the voltage. Your measurement method is not correct.

[trufla]

Re: MSI GL62 7RDX not charging, not powering on

Alright, done as instructed and the readings are as follow:
Mosfet 1
Pin 1 - 19.7
Pin 4 - 7.6
Pin 8 - 1.4

Mosfet 2
Pin 1 - 0.9
Pin 4 - 0.73
Pin 8 - 1.4

[mcplslg123]

Re: MSI GL62 7RDX not charging, not powering on

Mosfet 1- Pin1-SOURCE, PIN4-GATE, PIN 8-DRAIN. I dont know which mosfet is used here. Please mention the markings on mosfet1. Seems like P channel mosfet for which Gate has to be lower then source. So all the conditions looks good but still you dont have 19V on pin8. So pin8 is likely having low resistance or shorting in +19V line. The mosfet1 or mosfet 2 could be bad as well. Now check the following:

01. check mosfet 1 and 2 in meter set to diode mode. Put black probe on pin1 and red on pin4 and write the readings. Again same way between pin and pin8 also. this way we'll have an idea if the mosfet itself is bad.

02.Measure resistance on pin8 of mosfet1-meter set to ohms mode .

[trufla]

Re: MSI GL62 7RDX not charging, not powering on

Hello !

Alright, so did as instructed and:

Mosfet 1 - 4309 RSACP
Mosfet 2 - 4413 BA652Z

Diode mode test.

Mosfet 1
Pin 1 -> 4 = 16.07
Pin 1-> 8 = nothing

Mosfet 2
Pin 1 -> 4 = nothing
Pin 1 -> 8 = 6.7

Mosfet 1, Pin 1 to 8 resistance - 0.400

Btw, thank you so much mcplslg for your guidance ! Im learning a bit more with your every reply thank you thank you !

[mcplslg123]

Re: MSI GL62 7RDX not charging, not powering on

Both are P channel mosfets. reading does not looks good. Remove the mosfets and measure them out of circuit. One of them is shorted. Btw, I asked for resistance on pin8 of mosfet1 and not between pin1 & pin8. Dont apply power while mosfets are removed from mb. Once you take the mosfets out from circuit measure them the same way between S-G/S-D/G-D
S=SOURCE=PIN 1-2-3
G=GATE=PIN4
D=DRAIN=PIN 5-6-7-8

[trufla]

Re: MSI GL62 7RDX not charging, not powering on

Aha another lesson learned. Acknowledged will desolder both mosfets and measure them as instructed shortly !