Toshiba L650 Burned Mosfet

Hi all,

I'm working on a Toshiba L650 motherboard is "6050A2332301-MB-A02" the Q6002 Mosfet was burned, all plastic melted, I replaced this mosfet, I now get 19.5 vold on drain, 3.412V on source, and next mosfet Q6005 also getting 3.412V on both sides.

Problem is still no power. On VREG3 I am getting 3.3V, VREG5 and VIN are both getting exactly 3.412V (same as mosfet drain)

What do you think the problem is?

 

My understanding, is the problem must be on the VIN line, because it is not getting 19V, and VREG5 (which is 5v always line) is only getting as much as the VIN line, so it is limited by VIN voltage, does that sound about right? So I need to find out why 19v isn't being produced first? Just not sure how. I don't know if the Q6002 Mosfet should have 3.4V on source side, or if it should be 19v.

If anyone can point me further I would be very grateful! Thanks.