MSI GS66 Stealth 11UE-007 | No power

[Eniaro]

The history behind this PC is... it has passed through many hands trying to repair it
The back story the screen was flickering and someone before me changed the screen, it apparently worked then went back to flickering then eventually stopped powering on.
I used a thermal camera to find out what gets hot. The area registered 40+ °C simply by plugging in the charger. I used freeze spray to isolate, which lead to 1285B



I do not have the schematics or board view but requested it

I don't see any part physically damaged so far should I take the gamble and change it?

[Vesko356]

Re: MSI GS66 Stealth 11UE-007 | No power

What is the value in Ohms of the resistance to ground at VREG3, VREG5, SW1, SW2, VIN? Remove the power adapter and the battery before measurements.

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[Eniaro]

Re: MSI GS66 Stealth 11UE-007 | No power

VREG3 004.9 / 005.0 Ω
VREG5 open
SW1 open
SW2 open
VIN open

[Vesko356]

Re: MSI GS66 Stealth 11UE-007 | No power

VREG3 004.9 / 005.0 Ω
VREG5 open
SW1 open
SW2 open
VIN open

In short it's a bad news I'm afraid, 3.3V LDO line is in short, which in 99% of the cases means dead multi-controller.

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[Eniaro]

Re: MSI GS66 Stealth 11UE-007 | No power

In short it's a bad news I'm afraid, 3.3V LDO line is in short, which in 99% of the cases means dead multi-controller.

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Are you saying replacing 1285B (TPS51285B) may bring it back to life or I should remove 1285B (TPS51285B) and look for shorts?

[Vesko356]

Re: MSI GS66 Stealth 11UE-007 | No power

Are you saying replacing 1285B (TPS51285B) may bring it back to life or I should remove 1285B (TPS51285B) and look for shorts?

Remove the chip and check again VREG3 line for short, I'm pretty sure you'll still have a short there, if that's the case you can inject 1V/1A to see if the SIO chip is shorted, if it is getting hot you must replace it.
If you're lucky enough after removing the TPS51285B chip from the motherboard VREG3 line will not be shorted anymore which means TPS51285B is faulty and you must replace it, but the first scenario is most likely the case here - shorted SIO chip is the "usual suspect" in 99% of the cases as I already said.

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[mcplslg123]

Re: MSI GS66 Stealth 11UE-007 | No power

Besides SIO, sometimes PCH part of SOC also gets shorted when +3V LDO is shorted to Ground.

[Eniaro]

Re: MSI GS66 Stealth 11UE-007 | No power

Remove the chip and check again VREG3 line for short, I'm pretty sure you'll still have a short there, if that's the case you can inject 1V/1A to see if the SIO chip is shorted, if it is getting hot you must replace it.
If you're lucky enough after removing the TPS51285B chip from the motherboard VREG3 line will not be shorted anymore which means TPS51285B is faulty and you must replace it, but the first scenario is most likely the case here - shorted SIO chip is the "usual suspect" in 99% of the cases as I already said.

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Pardon my noobness, I did not understand what SIO/multi-controller meant after looking it up I understood what to look for which led me to reinspect the board.



ENE KB9548GF2 appears to be damaged



In an attempt to find out more about this chip, I found another MSI model & a thread "MSI GE76 Raider 11UH Super I/O replacement" that uses the same ENE KB9548GF2 SIO and having similar issues

[mon2]

Re: MSI GS66 Stealth 11UE-007 | No power

100% damaged. This is a BGA packaged component.