MSI Raider GE75 - Not posting, probable dead CPU

[FiguringITout]

Hello, today I'm working on this lovely MSI Raider GE75 gaming laptop which I bought to flip. Unfortunately, I believe the CPU is toast but I wanted a second opinion before I chucked it into my spare parts bin. I will not have most tools with me today as I'm away from my workbench but I have the basics (a good multimeter, a horrible iron, a solid screwdriver, and my trusty thermal cam). I do not have the original 230w charger, but I have a Dell 180w which was sold with the device and reportedly "worked fine for them".

Specs: I7-10750H, RTX 2060, 32GB RAM (unknown manufacturer)

Board# MS-17E91 Ver:1.0, no schematics or boardview found

The laptop gets power in with the Dell charger, but when you hit the power button it lights the power button but does not turn on. From there I took the fast route and measured the DC-IN mosfets which had low readings. I also measured the CPU coils which had low readings, but not a dead short.
M1 - SD: 450kohm, SG: 700kohm, GD: 240kohm
M2 - SD: 800kohm, SG: 400kohm, GD: 240kohm

Coils from left to right - 2.6ohm, 1.9ohm, 1.9ohm, 1.9ohm, 1.9ohm, 5.20hm.

With the heatsink off, I see the CPU rises briefly in temp to around 80c which astounds me as I didn't think CPU shorts could get that hot, but I'm not skilled enough to know what I'm looking for. This is why I believe it to be dead, but also why I wanted to ask for a second opinion.



Is she dead, or did I assume correctly with those low mosfet readings? Are there any other checks we can do before I call it?

[FiguringITout]

Hello,

Please note that I mistook the source and drain pins so any markings would be swapped. Updated readings below

M1 - SD=470kohm, SG=240kohm, DG=680kohm
M2 - SD=650kohm, SG=rises from 180 to 240kohm, DG=643kohm

Side note: I've noticed my multimeter sometimes shows different readings depending on which directions the probes are placed. For example Mosfet 2, red on gate, black on drain shows 600kohm, but swapped shows 415kohm. I'm definitely in resistance mode, but my multimeter shares diode and continuity modes on the same dial selection. Would this cause the weird readings or would that be something else?

[mcplslg123]

First thing to do is get the correct rated adapter meant for this machine ,i.e, 230W. you cant power a PC rated for 230W with an underrated aapter.
Dell has a psid in adapter whereas msi perhaps not. So first thing to do is look for correct adapter.
The resistance to GND reading on cpu coils seems correct for this platform.

[FiguringITout]

First thing to do is get the correct rated adapter meant for this machine ,i.e, 230W. you cant power a PC rated for 230W with an underrated aapter.
Dell has a psid in adapter whereas msi perhaps not. So first thing to do is look for correct adapter.
The resistance to GND reading on cpu coils seems correct for this platform.

That is good to hear coil-wise. I have ordered the correct adapter which should arrive late next week. I do not believe this board uses any pin like the Dell PSID, but it would be a good idea to get one anyway. I will update this thread next week once the power supply arrives.

As for the CPU heating up once the power button is pressed, is 80 celsius ok in such a short span? I do not work on enough high-powered laptops but it seems a bit high for my liking.

[mcplslg123]

H type cpu's heat more then normal laptops. So may be normal.

[FiguringITout]

I received the charger earlier today, but I am not at my workshop during the weekday so my tools are limited. The device still does not power on but is charging the battery.

Voltage to the mosfets is 19.5v source/drain for both, 9.3v to the high side gate, and 8.3v for the low side gate. Upon power on, all CPU coils get a very unsteady 0.9v excluding the rightmost one in my first picture which has nothing.


I flipped the board and found an area of concern, this REALTEK ALC1306-CGT has a burn mark. I may have missed it on my first inspection. There are no blown capacitors in the area, but the one in line with the burned chip/trace is reading 2kohm resistance to ground. I can't find a spec sheet on it, so I'm not entirely certain what it is, but it may be a DC-DC voltage regulator, which I'm going to guess is probably critical to the laptop. I will order some replacements and swap them out. If a schematic could be found for the board or this chip, I'd love to know exactly what that capacitor is supposed to be.

[mcplslg123]

De solder the chip and then try to power on. Seems like audio IC.

[FiguringITout]

De solder the chip and then try to power on. Seems like audio IC.

I have desoldered the chip, and the laptop still isn't powering on. However, it is showing slightly different behavior from before. Pressing the power button shows the power LED on, but it turns off much quicker. Previously, it would take ~15 seconds to allow me to turn the device on again, but now it's nearly instant. Another thing that may be good, is that the CPU coils now have a steady .9v before the device turns off whereas before it was very unsteady.

Something of note, the CPU's coils' resistance to ground has lowered to 1.6ohm from 1.9ohm. I still think this is low, but I will leave you to decide.

I have high hopes for this audio ic, as the symptoms have changed slightly. If you also agree, I can order the replacement chip.

[mcplslg123]

No point ordering the audio Ic at this stage as mb should give display without audio IC-so something is still wrong.
What is the resistance to GND on 5V and 3V coil?
Look for dc-dc converter for 3V/5V and measure the resistance to GND on the switched side(VS rail).

[FiguringITout]

I found this chip, which according to the datasheet is the step-down converter. You'll note this lovely hole near the SW1 pin, which measured 2.8kohm compared to SW2 which measured 9kohm. I also measured the 3v and 5v output, of which VREG3 had a resistance of 102ohm as compared to 1mohm from VREG5.

Something important: I inspected this chip when I got the laptop, as it produced some heat upon startup, but I did not see that hole on the top. I did not have the proper charger then, so my best guess is that this chip was already faulty, but the charger didn't have enough power to pop that hole on top.

[mcplslg123]

Remove this IC and remeasure resistance to GND on 3V LDO/5VLDO.

Warningont put power while this chip is removed.

[FiguringITout]

I removed the IC and the new resistance for VREG3 is 200kohm, with the 5v being its same measurement 1mohm. The switches are still low, but that may be by design. So should I order this chip and get it installed to see what happens?

[mcplslg123]

VREG3-200 Kohms
VREG5-1 Mohms
If thats correct,order a replacement chip and try.