P6T won't start when EATX12V is connected

[Joemanvn]

I bought a cheap motherboard Asus P6T Deluxe of Ebay with i7 920, won't post or boot when I connected EATX 12v port. I tried the PSU from the other computer and it didn't work either. I saw the PSU fan runs and the drives light up when the EATX12V isn't connect, but when it connected then i press Power button on PC Board, saw the ligjt flashing and turn PSU fan off. I took heat sink off, then saw 1 mosfet 9025L PBm signed burn, use multi meter measure all other the showed up 9.6 k/ohm, except the 1 with signed burn nothing showed up, is it shorted? How can I replace it? I got heat gun set up 300 celsius with small tip tried to lift up, but seems hard to remove, Any suggestions would be appreciated. Sorry newbie, don't know where to load image.

[stj]

Re: P6T won't start when EATX12V is connected

the motherboard has a shorted part on the 12v line for the cpu.
i'v seen this and it's usually one of the fets near the cpu cocket.

[Joemanvn]

Re: P6T won't start when EATX12V is connected

the motherboard has a shorted part on the 12v line for the cpu.
i'v seen this and it's usually one of the fets near the cpu cocket.

Yes, the one under heatsink, don't know which tool easy to remove it, does not affect the surface, thanks

[crash-cyberdrive]

Re: P6T won't start when EATX12V is connected

Yes, the one under heatsink, don't know which tool easy to remove it, does not affect the surface, thanks

That is one ugly FET, by the way it died looks like a bad PSU caused that.
Anyways, Test them all thoroughly, and try to have same or better specs MosFet.
Now to remove the fet start slow, preheat the area you will be working on; as you can see the board itself is a heatsink for the mosfet. Heat on both sides at about 160-180C. Do for about 3-5 minutes.
Increase temperature to about 250C moving the air heat gun (never keep in one spot). Add a small amount of rosin flux or clean flux, it will help to liquefy the solder. Do for about 1 minute
Lastly increase temperature to 350-360C for no more than 30 seconds with tweezers be ready to take off the part.

Clean the pads with solder iron and solder wick adding flux helps.
Its my personal preference to use 62/36/2 for this kind of repair for its stability because of the silver content. But is not critical unless it is for a critical application.

Just melt a bit on the pad and place the replacing component and re-flow with the air heat gun.

Been doing this very same procedure for some time with multiple boards with very good results.
Hope you are able to fix your P6T Deluxe.

[sunilnjarakkat]

Re: P6T won't start when EATX12V is connected

P6T asus common problem-mosfet PH9025L 25V-66A

[mikan]

Re: P6T won't start when EATX12V is connected

I have an xfx x58i which is the same generation at least, with no power when you press the power button. Forcing the power supply on the boot code is just 00, and no bios reaction.

I also have a p6x58d that is basically the same as the p6t which runs for a random amount of time, usually around 5 minutes, but had it on and running as long as an hour before it locks up. This happens even in bios..any idea on that one especially?

Both these boards have broken pins in the sockets, but I've attempted repair of them. The p6x58d is just a ground pin.

Would a broken pin in the xfx on a pin which is dealing with memory prevent the system from turning on the power supply, or would it be something else?

I've been searching for any x58 lga1366 schematics in order to understand power troubleshooting better, but not had any luck with this generation of boards. Not one schematic seems to be available anywhere on the web for them.