MSI Laptop GP62M Leopard - MS-16J91_1 no power

[corrize]

Hello, I have a MSI Laptop GP62M Leopard - MS-16J91_1
The laptop is full dead : no led, nothing at start button.
I'm working on motherboard disassembled. I measured 19v at high side mosfets but 9.7v at gates of both. It is normal pls ? Is it the charging chip providing the gates voltage ?
3-5v chip is good but it provide 4.75v : too low ?
No 3.3v at bios chip
19v rail is ok on board, but no voltage on anyt coil.
No short nowhere.
Not an easy one. I have schematic. What should I check first pls ?

[mon2]

Re: MSI Laptop GP62M Leopard - MS-16J91_1 no power

Link or post the schematic. If it is on this forum, just link it.

Post the voltages on the first 2 mosfets.

Start with the charger IC. Post all voltages on the charger IC.

Next, remove all power. Meter in resistance mode (2k is good). Then measure the resistance to ground of each coil. Red meter lead on coil. Black lead to any good ground.

Post any low resistance reading.

[mon2]

Re: MSI Laptop GP62M Leopard - MS-16J91_1 no power

Found the schematic in my database.

According to other techs, check PR214 which is a common fault for the logic board that will not power on. The resistance for PR214 is too large.

Check the resistance with NO power to the board. Meter in resistance mode (2k setting is ok). Then check the resistance across this part with the meter.

What is the reading ? It should be about 1.8K ohms. If the reading is much higher, then remove off the board and check the resistance again for this part.

Again, should be about 1.8k when off the logic board. Replace or solder back with a good 1.8k resistor.

[corrize]

Re: MSI Laptop GP62M Leopard - MS-16J91_1 no power

Thanks mon2, it is a good way : coil of 3v (from the 3-5v chip) is shorted (0 Ohms). I'm following this way.
PR 214 ; 1.25k measured, I guess it's good
I post schematic. Where do you find the boardview pls ?
I keep in mind the 9v at gates of high side mosfet and check the IC charging. I will see that after.

[mon2]

Re: MSI Laptop GP62M Leopard - MS-16J91_1 no power

See attached for the boardview file. Hope it will load in your boardview file viewer. If not, post back.

[corrize]

Re: MSI Laptop GP62M Leopard - MS-16J91_1 no power

Thanks for boardview.
Update : I tryed to inject voltage (1.2v) on coil (shorted) of 3v (from 3-5v chip) with 4 Amp, and nothing, no hot spot nowhere on the board. I don't use thermal camera, I use my fingers. The board keep cold. Incredible.
I supposed 3v coil mosfet (PQ40) was faulty (drain-source shorted) but it is not hot, even with alcohol on.
Same with 3-5v chip.
Same with big chip (chipset) ; no hot spot.
Can I try with 5 amp ? It's a big MSI board, but 5 amp seems very high.

[mon2]

Re: MSI Laptop GP62M Leopard - MS-16J91_1 no power

Can you list the coil you are observing to be shorted to ground ?

With the meter on resistance mode (2k setting); red meter probe on coil & black meter probe to ground - the resistance reading is close to 0 ohms ?

Wait till we / others can review. There has to be a shorted part but want to see the details of the coil.

[corrize]

Re: MSI Laptop GP62M Leopard - MS-16J91_1 no power

0 Ohms between coil and ground. True short. It’s only coil shorted.
I can follow this short (0 Ohms) between drain and source of direct linked to this coil : mosfet (PQ40). Pin 1 2 3 (source) are to ground on schematic.
So I supposed this mosfet is faulty, because it sould be OL betwenn drain and source. But no hot spot on it.
I just tryed 5 amp and no hot spot nowhere. At this power, only big chips like chipset can keep cold. An The board is cold, cold.

I supposed short inside connector now. I will check.

[mon2]

Re: MSI Laptop GP62M Leopard - MS-16J91_1 no power

Which coil?

[corrize]

Re: MSI Laptop GP62M Leopard - MS-16J91_1 no power

The coilis directly linked with PQ40 : the name of this coil is : CHOCKE11
P45 in the schematic.

[corrize]

Re: MSI Laptop GP62M Leopard - MS-16J91_1 no power

I measured caps shorted on chipset’s PCB ; 0 Ohms. It’s weird, I sent 1.2v 5A and it keeped cold, even with temperature prob taped on it, the temperature don’t moved.
So chipset dead.
Thanks for your help.

[abudo]

Re: MSI Laptop GP62M Leopard - MS-16J91_1 no power

See attached for the boardview file. Hope it will load in your boardview file viewer. If not, post back.

Hi thanks for sharing this. I just have a problem opening this on openboardviewer. Which boardviewer should I use? Thanks

[mon2]

Re: MSI Laptop GP62M Leopard - MS-16J91_1 no power

Use the boardviewer posted on this thread:

https://www.badcaps.net/forum/showthread.php?t=117486

[abudo]

Re: MSI Laptop GP62M Leopard - MS-16J91_1 no power

Hi thanks for you prompt reply.

I have same model with same problem (no power)

I have a question. I can measure 19v on PQ41 in pin 5. What could be the voltage output from PQ41 pin 123 and pin 4? Im not getting any voltage output on this chip. Whats the best thing to do?

Your tips will be highly appreciated

[mon2]

Re: MSI Laptop GP62M Leopard - MS-16J91_1 no power

See attached. Start with the power adapter connected and confirm the voltage to ground of the noted points of interest.

Need to know if the DCin mosfets are working to power the charger IC.

Meter in DC volts (30V or higher) scale.

Red probe on the points to measure. Black to ground (shield is ok).

Post each measurement.

[abudo]

Re: MSI Laptop GP62M Leopard - MS-16J91_1 no power

See attached. Start with the power adapter connected and confirm the voltage to ground of the noted points of interest.

Need to know if the DCin mosfets are working to power the charger IC.

Meter in DC volts (30V or higher) scale.

Red probe on the points to measure. Black to ground (shield is ok).

Post each measurement.

Hi,
Yes I can measure 19v on these points

[mon2]

Re: MSI Laptop GP62M Leopard - MS-16J91_1 no power

Review the net name for the power (VCC) pin of the flash memory IC. Then search for that net name till you find the regulator who creates that power rail.

Check if that rail is being enabled or not.

Post your findings.

[abudo]

Re: MSI Laptop GP62M Leopard - MS-16J91_1 no power

thanks I will chase the rails on BIOS chip.

Thanks again