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SOLVED Is my mobo missing mosfets ?

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damsanchande

New Member
Joined
Apr 5, 2016
Hello and have a nice day everyone!

Please help me with this dumb question and bear with me cause i'm a complete noob about mobo. And my English also.

I got my hand on an old Asus M4A79XTD EVO. It won't POST so i decided to clean it up. After removing the VRM Heatsink, i noticed that there are 2 white slots where mosfets should be placed ( i think ).

So is my board missing 2 mosfets or that's the design ?
Sx3Gv2q.jpg


Update: Thank you all! The mosfets definitely got pulled out by someone, or something? The mobo wasn't made this way!
 
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Mr.Scott

Beamed Me Up!
Joined
Jun 9, 2013
Yes sir. Most definitely missing. They were there at one time because there are pieces left.
 
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Johan45

Benching Team Leader Super Moderator
Joined
Dec 19, 2012
They didn't stick to the heatsink did they?
 

Dolk

I once overclocked an Intel
Joined
Mar 3, 2008
Um, this shouldn't be possible. Either you missed the blue fire, or a time goblin stole your FETs.

Solder doesn't get weak over time like this. Either this was a very badly put together motherboard, or something else is very wrong.

Can you clean up the picture on one of the FETs? Did you see any black smudges around the area or coated on the thermal pads of the VRMs?

This is a total what if your not jerking us around :)
 
OP
D

damsanchande

New Member
Joined
Apr 5, 2016
Um, this shouldn't be possible. Either you missed the blue fire, or a time goblin stole your FETs.

Solder doesn't get weak over time like this. Either this was a very badly put together motherboard, or something else is very wrong.

Can you clean up the picture on one of the FETs? Did you see any black smudges around the area or coated on the thermal pads of the VRMs?

This is a total what if your not jerking us around :)

The area looks really clean. The heatsink looks clean. No evident of any fire. I will upload a closer photo right away. This looks like either the board was made this way or someone took them out with a torch.

And no, sir, i'm not fooling around. I'm trying to confirm if this is a missing case or not to fix it. Bear with me, sir.

mXzCWPX.jpg
 

Mr.Scott

Beamed Me Up!
Joined
Jun 9, 2013
They were there at one time. The plates are still on the pad and you can see where the legs were imprinted into the solder. Those were ripped off with the sink is my best guess. Maybe not by you, but that's what happened. Somebody put the sink back on and you wound up with the board. That's why you got a couple posts out of it before it fried. If you bought this used, that guy screwed you.
 
OP
D

damsanchande

New Member
Joined
Apr 5, 2016
Well, this mobo was a gift. The old owner used to OC x4 955 BE to 4.1 with this mobo and used it that way since January. Then it got worse. He could get posts sometimes, sometime he doesn't. So he gave it to me. And now i've found this out. I'm just surprise that a mobo missing 2 mosfets could live that long.

Do you guys think rejoining new mosfets could make it alive again ?
 

Dolk

I once overclocked an Intel
Joined
Mar 3, 2008
Agree with Mr. Scott. There was a FET there and now it is gone. What happened? The board became too hot for whatever reason, and the FET desoldered itself from the board. When its like that, the bubbling solder can push the FET to explosion point. The other user probably never even saw a FET after the board died. Most likely it crumbled up into black little specs. Hard to notice unless you know what you are looking for.
 
OP
D

damsanchande

New Member
Joined
Apr 5, 2016
Agree with Mr. Scott. There was a FET there and now it is gone. What happened? The board became too hot for whatever reason, and the FET desoldered itself from the board. When its like that, the bubbling solder can push the FET to explosion point. The other user probably never even saw a FET after the board died. Most likely it crumbled up into black little specs. Hard to notice unless you know what you are looking for.

Seriously ? :shock: it could gone exploded like that ? The only think odd i noticed when cleaning the board is black sticky dust around the VRMs area. Please don't make fun of me cause i'm a very gullible person. :)
 

Dolk

I once overclocked an Intel
Joined
Mar 3, 2008
The mobo is most likely fine. The VRM senses each one of the phases current. It would have seen a bad balance of current in the area. Actually, OP, you're pretty lucky. Those were the high side FETs that pulls the 12V down to the inductors. If it had been the low side FETs that blew, you might have lost a CPU before the VRM noticed something. You could solder on new FETs, but they need to be perfectly identical the originals in order to have a clean power.

...The only think odd i noticed when cleaning the board is black sticky dust around the VRMs area. ...

Those were the FETs. :)
 

WhitehawkEQ

Premium Member
Joined
Dec 6, 2010
It could be bad solder connections, if the solder was week, then it is easy to dislodge the parts. I worked in electronic manufacturing and seen bad soldering.
 
OP
D

damsanchande

New Member
Joined
Apr 5, 2016
I'm searching for identical Fets now. I will update soon if i manage to restore this baby :D
 

trents

Senior Member
Joined
Dec 27, 2008
Could be the original owner cannibalized the board to replace mosfets on another board.