DFI NF2 infinity repair questions

[speed bump]

Hi,

This weekend I lent my DFI nf2 infinity to buddy so could test out his BH-5 becuase his NF7 hates high ram speed. Anyway instead of using the 3.3v already provided by the board he through in a DDR booster and procceded to fry the memory VRM circuitry.

I would like to repair the board if at all possible it doesn't appear that the traces on the motherboard were burned so I'm thinking that its one of the little black pieces(I can't rememebr what they are called at the moment) next to the memory slots and one next to the AGP slot were burning hot when it died though.

So what i'm wondering is it possible to fix this and what exactly did I kill?

Thanks in advance and i'll post pictures later.

[persivore]

The Vdimm regulator uses the MOSFETs under the Dimm slots to provide Vdimm, and its likely that those will be damaged. If you can remove them, it should be possible to replace them (if you can find suitable replacements).

[speed bump]

Alright any idea how I can test them or should I just place an order to Mouser ASAP and replace all of them?

I also added a pic with what was hot and that.

Now hopefully I can find part numbers and datasheets.

[persivore]

The 2 MOSFETs closest to the AGP slot are for Vagp and Vdd. The Vdd MOSFET is almost always hot anyway.
The best way to test the MOSFETs properly would be to remove them and test them off the board, and if you are removing them, you might as well replace them (possibly with ones of better spec than the origional ones)

[speed bump]

Any idea how test them once they come off the board.

They should be really easy to unsolder as nothings in the way and I have a new smaller soldering iron to play with.

[persivore]

Once you remove them, you need to check the resistance between the source and drain pins. Doing that will tell you if the MOSFET is internally shorting (you will get a resistance of about 0 ohms if it is). If its not internally shorting, you can put a voltage of about 5 to 10v onto the gate pin and check if the resistance changes. If it doesn't, the MOSFET is probably dead.

When you test them, you will need to get the + and - leads the right way around, otherwise you will probably not get any resistance reading between the source and drain. You can find out which pins are gate, source and drain from the MOSFETs data sheet.