DH5VF LA-F952P Motherboard short circuit

[mon2]

Re: DH5VF LA-F952P Motherboard short circuit

Can you configure your meter into resistance mode but take the measurements across the mosfet pins?

So for example,

Source & drain

One meter probe to pin #1 (source) and other meter probe to drain pin #8.

What is the reading?

Repeat for the other measurements and post your updates.

[Oj computer]

Re: DH5VF LA-F952P Motherboard short circuit

To my own view it seems as if the MOSFET is normal.
But I observe malfunctioning on pu1304 (lm393) ic
Where pin 1 = 0v, pin 2=1, pin 3=0v, pin4=0v, pin 5= 1.7, pin6 =1.4v pin 7= 3.1v and pin 8= 5v.
I don't know if the ic is working normally.

[Oj computer]

Re: DH5VF LA-F952P Motherboard short circuit

Oh I'm sorry I've drop my message b4 I could see ur post
I'll measure the MOSFET across the pin tomorrow

[mon2]

Re: DH5VF LA-F952P Motherboard short circuit

Sounds good

[Oj computer]

Re: DH5VF LA-F952P Motherboard short circuit

Sorry for the late response pls I just arrived from traveling.
Measurement drain to source 305 and source to drain 307.
Thanks

[Oj computer]

Re: DH5VF LA-F952P Motherboard short circuit

Pls presently I also have the same board (LA7901p) anytime the processor is inserted the 19v rail will be shorted but when the processor is unplugged there will not be any short at all. I've used up to 5 different processor still same thing.
Pls what might be happening, I've checked all through but to no avail.
Thanks.

[mon2]

Re: DH5VF LA-F952P Motherboard short circuit

The measurements are not clear. Review post #21.

What is the meter scale used?

What are the unit of the measurements?

Ohms ? Kohms ? Mohms ?

[Oj computer]

Re: DH5VF LA-F952P Motherboard short circuit

I tuned meter to 2k
And I was getting that measurements
Thanks

[Oj computer]

Re: DH5VF LA-F952P Motherboard short circuit

Please don't forget me on post #26 as well.
Thanks in anticipation

[mcplslg123]

Re: DH5VF LA-F952P Motherboard short circuit

Pls presently I also have the same board (LA7901p) anytime the processor is inserted the 19v rail will be shorted but when the processor is unplugged there will not be any short at all. I've used up to 5 different processor still same thing.
Pls what might be happening, I've checked all through but to no avail.
Thanks.

Very likley one of the mosfets related to vcore circuit is shorted or leaky. Another reason can be Vcore regulator IC.

[Oj computer]

Re: DH5VF LA-F952P Motherboard short circuit

Ok sir I'll check

[Oj computer]

Re: DH5VF LA-F952P Motherboard short circuit

Yes the v core coil is shorting and I lifted the coil up and the shorting is not from the ic but from the output end of the coil.

[Sephir0th]

Re: DH5VF LA-F952P Motherboard short circuit

I don't really understand how someone can create so much confusion in one thread, tbh.

It is even discussed a completely another board in the thread title.

However, for LA-7901P schematics are widely available and easy to source, so i also really don't understand why every answer here is still very vague.

So in future, PLEASE, share EXACTLY on which components and/or power rails you're working on. I guess the main suspects here are PQ700 and PQ704(?) since i completely agree with the assumption of mcplslg123, that one of the high sides is internal shorted. That the main power rail reaches a healthy value as soon as one of the coils is lifted should be more than enough explanation.

And please, always share EXACT measurements in future. How do you expect that anyone here can help you out when everything consist of guess work and vague observations?

So what is the actual resistance to GND at +VCC_CORE?
Which coil did you lift, so the that the main power rail came present again? If you still don't know, it's time to confirm now.

Thank you

[mcplslg123]

Re: DH5VF LA-F952P Motherboard short circuit

@Sephir0th, strongly agree with your observation but realy we cant help. The job of anyone who is giving advice/suggestion to troubleshoot is to point you close to the fault and thats the clue where OP has to built on. Its not our job to literally solve a case till the last point. Remember, mb is on your table and there are limitations on our part without physically having the board in front of our eyes.

[Oj computer]

Re: DH5VF LA-F952P Motherboard short circuit

Good day sir.
Pls I have HP folio 9470m it is power and stock at 0.170 on DC reading.
I checked charging ic and seen to be ok but 3v/5v looks somehow. any time check pin 1 or pin 2 of the ic the DC reading will reduce to 0.03 and the ic will be heating up and once probe is removed from the pin it will go to its normal position.
I've changed the ic but still the same.
Ic tps 51123
Kindly be help sir.
Any response will appreciative.
Thank you in advance