Nikos
pa102fdg
qnb2n0508

 

is it exactly as it is written and do u have a DMM?

 

Yes and here's its datasheet: http://www.google.com/url?sa=t&rct=...sg=AFQjCNFu5OGt3Xnwis-SEj4JjPV3w6fd4A&cad=rja

Yes, I have a DMM.

 

U said it shows continuity through out the pins, right ?

If so. Just short the G and S for a few sec and then check for short circuit. If you get dead short across all three, u need to replace that FET.

 

U said it shows continuity through out the pins, right ?

If so. Just short the G and S for a few sec and then check for short circuit. If you get dead short across all three, u need to replace that FET.

Yes the three pins (G, S, D) are all dead short. Definitely this FET is dead.

My question is:

Is there a possibility that other components are damaged also to some extent? Or only that single FET was damaged?

I cannot yet notice any anomalies in my system except for those two headers.

 

Highly Unlikely other that a resettable fuse.

Remove and measure the voltage. This will make sure that no other component is at fault

 

Is there always a fuse in the motherboard? Where will I see it?

You mean when I remove the FET and then I do a continuity test again the three pins should be shorted IF IT REALLY is broken? If they are not shorted then some component in the board is affected that makes the FET pins shorted?

 

Remember that FET controls the drive (well did) to the fans so whilst it presents a short circuit it allows (full) drive to the fans. Removing it will remove any drive to the fans.

So don't run the board too long in this condition doing your measuring, or provide a temporary alternative drive.

 

Remember that FET controls the drive (well did) to the fans so whilst it presents a short circuit it allows (full) drive to the fans. Removing it will remove any drive to the fans.

So don't run the board too long in this condition doing your measuring, or provide a temporary alternative drive.

So that explains why my fans are running at full 12V.

If I remove the drive FET, in what way can it be detrimental?

 

The fet acts as a voltage controlled resistor to control the speed of the fans.

If it is shorted there is no control.

If it is open or removed there is no supply to the fans so they don't run.

 

U need to remove it to make sure...

As long as the CPU fan is working, you can power up the board without any peripherals.
All u need is the processor and graphics to check in to bios.

After powering up u can use DVM to measure the header voltage levels when u are in bios.

But just don't go & on do tht. Cause if you cannot remove an SMD easily I doubt you can measure voltages the way we do.

PS. I said a resettable. It means it will reset when power is removed, so U need not to worry about it. But the FET might be shorted. And any other component may not be at fault

 

The fet acts as a voltage controlled resistor to control the speed of the fans.

If it is shorted there is no control.

If it is open or removed there is no supply to the fans so they don't run.

Yeah but why were you suggesting not to run the board for too long without the FET installed?

U need to remove it to make sure...

As long as the CPU fan is working, you can power up the board without any peripherals.
All u need is the processor and graphics to check in to bios.

After powering up u can use DVM to measure the header voltage levels when u are in bios.

But just don't go & on do tht. Cause if you cannot remove an SMD easily I doubt you can measure voltages the way we do.

PS. I said a resettable. It means it will reset when power is removed, so U need not to worry about it. But the FET might be shorted. And any other component may not be at fault

How will I be able to conclude, through measured voltages, that no any other components were damaged?

What are you referring to when you said "you need to remove the FET to make sure"? What am I making sure here?

Sorry, just need to confirm.

 

By removing the FET you can be sure that you had actually discharged the gate in order to measure DS for shorts.

And by removing you can check continuity across GDS pads on the board to make sure that the components connected to pads are not creating a short and by running the board u can measure gate for DC controller or PWM signals to see that gate actually is being driven properly

 

By removing the FET you can be sure that you had actually discharged the gate in order to measure DS for shorts.

You mean the gate of the FET or the gate terminal in the board? What do you mean by "DS"?

Also, if the FET is destroyed by the incident that happened, what could have caused the hotness in the wire of the fan? I noticed that when I connect the fans the wrong way AGAIN, nothing happens NOW. No more hotness in the wire because I guess the FET is dead already?

 

GSD, Gate, source and drain.

The wire heated due to reverse connection, I have to see what blew to say anything

 

GSD, Gate, source and drain.

The wire heated due to reverse connection, I have to see what blew to say anything

Ok. I'll try to remove the FET in order to have these measurements. Can I use a soldering iron for this matter? Or do I really need to use heat air guns?

 

Well I would not recommend a soldering iron if it cannot control temp. even then I might not recommend unless u have good experience with soldering.

And I might not yet recommend u to remove it with hot air gun unless ur familiar with removing components near plastic mount.

SORRY.....rest is upto u..ur board u know.

 

Alright.

Another thing, why wasn't the fan destroyed when its wires went hot during the incident?

 

I would say ask the fan...

for pete's sake ...I really dunno how ur fan's internal circuitry is.

It could have a reverse protection diode that just happen to be strong enuf to burn the wires.

Or may be that it's not yet it's time to die.

 

I would say ask the fan...

for pete's sake ...I really dunno how ur fan's internal circuitry is.

It could have a reverse protection diode that just happen to be strong enuf to burn the wires.

Or may be that it's not yet it's time to die.

Lol, ok.

I'm off to replacing the FET. I only have a soldering icon that has an output of 20W, I hope that is enough. I'm an Electronics Engineer and have some background with soldering, so yeah.