Burned PCB Pad

[baElectronic]

Hi,

I'm repairing my plasma TV, and the pad under a surface mount mosfet is charred on the Y-Sustain. I'm reluctant to reuse the board, but a replacement Y-Sus is $100+. I read online that I can scrape down to good board material and refill with an epoxy/fiberglass mixture: http://electriciantraining.tpub.com/14186/css/14186_128.htm


I've attached pics of the front side and the back side of the board.

[Psi]

I would give it a really good clean with solvent, then give the area a sand with 400 grit sandpaper and see how it looks.
That will tell you if the burn marks are just on the surface or not.

If it looks impossible to solder a new mosfet in you may have to mount it on an external heatsink and run short wires to the pcb.

[baElectronic]

I would give it a really good clean with solvent, then give the area a sand with 400 grit sandpaper and see how it looks.
That will tell you if the burn marks are just on the surface or not.

If it looks impossible to solder a new mosfet in you may have to mount it on an external heatsink and run short wires to the pcb.

The burn is not a surface-level burn; I've scraped away some of the burned PCB material already. The blackened portion in the middle of the pad is where I scraped. I actually jumped the gun a bit and soldered on a new mosfet just fine without scraping away ALL the burned material, so I anticipate that I'll have a burning odor when I fire up the TV. I believe that the mosfet can be reattached after I scrape away the remaining burned material, but I was thinking about whether I need to fill the leftover crater.

[Zapro]

You won't have a burning smell after replacement of the part, worst case it stops smelling after a couple of weeks.

It can be a problem when the charred PCB material becomes conductive, and then it will give you problems, maybe start smoking and parts blowing up.

// Per.