MSI P65 Creator 9SE not booting after repair attempt

[mcplslg123]

Re: MSI P65 Creator 9SE not booting after repair attempt

When Drmos is shorted, 19V goes straight away to cpu. No injection or injection of voltage is not the issue here. You may keep on investing time on this repair but i strongly beleives its damaged SOC. Good luck.

[G33RT]

Re: MSI P65 Creator 9SE not booting after repair attempt

When Drmos is shorted, 19V goes straight away to cpu. No injection or injection of voltage is not the issue here. You may keep on investing time on this repair but i strongly beleives its damaged SOC. Good luck.

But what about the protections build into the circuit to prevent such situations, also the 19v PSU cuts directly of when something is shorted.
Could it not be possible that the CPU not got injected with the 19v as the protection kicks in or is it to slow for that matter ?

And yes, normally I don't spent such amount of time I literally spend hours and hour of time on it but I really want to try everything because it's for an old friend.

[reformatt]

Re: MSI P65 Creator 9SE not booting after repair attempt

There is no protection at all for a shorted high side MOSFET in a buck converter that I've ever seen. Its the reason so many CPU's get cooked and you have to replace the whole board. Don't believe NorthridgeFix that every shorted MOSFET he finds results in a working repair.

It could be done I guess, but that would add additionally circuitry to the design, increasing the cost. And the protection element would have to be beefy enough to prevent it destroying itself when activated.

They used to use a SCR 'crowbar' style circuit years back on power supplies for the +5V rail. When the voltage got above a certain threshold, the SCR would fire, shorting the output. This would then cause the power supply to shut down and prevent damage to the rest of the machine. Never seen that in anything in domestic electronics. They do after all, want you to just buy another one.

[mcplslg123]

Re: MSI P65 Creator 9SE not booting after repair attempt

Nothing more to add after @reformatt's comments.

[G33RT]

Re: MSI P65 Creator 9SE not booting after repair attempt

Nothing more to add after @reformatt's comments.

Normally today I will receive the SiC532 power stage which I think is also faulty.
When looking with a thermal cam it briefly lights up and mabe this causes the VRM controller to shut down.

When the VRM chip was removed the board powers up and stayed on (for some reason)

I will report back when I replaced that part.

[G33RT]

Re: MSI P65 Creator 9SE not booting after repair attempt

There is no protection at all for a shorted high side MOSFET in a buck converter that I've ever seen. Its the reason so many CPU's get cooked and you have to replace the whole board. Don't believe NorthridgeFix that every shorted MOSFET he finds results in a working repair.

It could be done I guess, but that would add additionally circuitry to the design, increasing the cost. And the protection element would have to be beefy enough to prevent it destroying itself when activated.

They used to use a SCR 'crowbar' style circuit years back on power supplies for the +5V rail. When the voltage got above a certain threshold, the SCR would fire, shorting the output. This would then cause the power supply to shut down and prevent damage to the rest of the machine. Never seen that in anything in domestic electronics. They do after all, want you to just buy another one.

I understand that this protection would be increasing the cost but they schould be consider putting it in high performance and gaming laptops.

And I know we are sadly living in a 'throwaway society'

[mcplslg123]

Re: MSI P65 Creator 9SE not booting after repair attempt

I understand that this protection would be increasing the cost but they schould be consider putting it in high performance and gaming laptops.

And I know we are sadly living in a 'throwaway society'

Simply they dont intend to lengthen the product life. Harsh but ugly truth.

[G33RT]

Re: MSI P65 Creator 9SE not booting after repair attempt

Can someone explain how a DrMOS got shorted by the faulty VRM controller?

I would like to better understand how this can happen.

Here a picture of the culprit:

[reformatt]

Re: MSI P65 Creator 9SE not booting after repair attempt

MOSFET's are chosen for these circuits due to their low on resistance. They can transfer large amounts of current without dissipating much in the way of losses (heat). So the switching from on to off and vice versa has to be as fast as possible (i.e minimise slew rate). That transition between on/off/on etc is where the losses are mainly encountered, in the form of heat.

So bad drive from the VRM (bad feedback for example due to liquid damage), will result in the FET being subjected to conditions that exceed it's maximum ratings. If the VRM believes the output voltage is low, it will drive the output stage harder. That's one failure mechanism.

[G33RT]

Re: MSI P65 Creator 9SE not booting after repair attempt

MOSFET's are chosen for these circuits due to their low on resistance. They can transfer large amounts of current without dissipating much in the way of losses (heat). So the switching from on to off and vice versa has to be as fast as possible (i.e minimise slew rate). That transition between on/off/on etc is where the losses are mainly encountered, in the form of heat.

So bad drive from the VRM (bad feedback for example due to liquid damage), will result in the FET being subjected to conditions that exceed it's maximum ratings. If the VRM believes the output voltage is low, it will drive the output stage harder. That's one failure mechanism.

So it could be possible that the VRM send to both mosfet's High and Low to open at the same time which result in a short to ground and this could be the result that the High mosfet got shorted.

[G33RT]

Re: MSI P65 Creator 9SE not booting after repair attempt

I also noticed that the 3 SiC631 DRMOS that is responsible for VCore only one stage works as only one of the 3 DrMOS briefly lights up on thermal camera.

Tomorrow I will check with my scope to see if any PWM signal comes to them.

[reformatt]

Re: MSI P65 Creator 9SE not booting after repair attempt

Pretty sure that's normal. The 2nd and 3rd phases are only used during high load to minimise ripple.

Exact failure mechanism I don't know. Just know from my experience with switch mode power supplies, bad drive always results in a shorted FET. You'll often find the main switching FET shorted in those, only to replace it and for it to short again. Driver is often the cause.

[G33RT]

Re: MSI P65 Creator 9SE not booting after repair attempt

Pretty sure that's normal. The 2nd and 3rd phases are only used during high load to minimise ripple.

Exact failure mechanism I don't know. Just know from my experience with switch mode power supplies, bad drive always results in a shorted FET. You'll often find the main switching FET shorted in those, only to replace it and for it to short again. Driver is often the cause.

Yeah I already thought that it was normal, the other two phases are only kicking in when the CPU needs more current.

[G33RT]

Re: MSI P65 Creator 9SE not booting after repair attempt

Update:

When the VRM controller chip is off the board, the board can be turned on and all voltages are present except: GPU Vcore and GPU Memory (and of course the CPU)

I was curious if I did voltage injection on the CPU what results I would get.

Attached is a photo with the results.

Does this look like a shorted CPU? (would like your opinion)

[Sephir0th]

Re: MSI P65 Creator 9SE not booting after repair attempt

2.5A sounds pretty much like toast. I wouldn't expect more than 1A or 1.5A.

[G33RT]

Re: MSI P65 Creator 9SE not booting after repair attempt

2.5A sounds pretty much like toast. I wouldn't expect more than 1A or 1.5A.

Auwch

Then I assume it's GAME OVER concern this repair attempt.

[reformatt]

Re: MSI P65 Creator 9SE not booting after repair attempt

V=IR, if it's 3 ohms, then that's the expected current. However, you're dealing with a device loaded with semiconductors so not as simple as that.

My take it with shorted high side FET's is replace it and see if Vcore comes up ok. Even with near dead short CPU's, these drivers will often still produce 0.9V or thereabouts since they are designed to supply many amps of current.

The key is whether the CPU is loading and executing code or not. Assuming you don't have a BIOS or RAM issue, you would determine this by looking at your input current via external power supply (without battery connected of course). A static figure usually indicates a dead CPU. I don't waste too much time on them and move onto the next repair.

[G33RT]

Re: MSI P65 Creator 9SE not booting after repair attempt

Yes I know it's a lost case.
I tried everything I could.
About that voltage injection, no battery was connected and 0.8 volt was injected at VCore which resulted in 2570mA @ 0.8v = 0.311 ohms.

Just for fun and giggles I also injected 0.8v into the GPU and it draws 1.8 Amp but the current kept rising and after a minute it draws 2.2 Amps.
Is this also a short or normal behavior for a GPU ?

[mcplslg123]

Re: MSI P65 Creator 9SE not booting after repair attempt

Seems like shorted GPU as well. I suggested not to waste time on this repair.

[reformatt]

Re: MSI P65 Creator 9SE not booting after repair attempt

You can't fix everything. Shorted PCH/CPU are the most common issues for most boards these days, despite what you see on YouTube.