VGA MOSfet permanently shorted and loss of MOSfet pad

[Nooy]

Hello everyone, I recently found this badcaps site and super Learn Electronics Repair youtube channel. And I wanted to learn how to troubleshoot power supplies and VGA cards and how to practice soldering, since I already have a properly defective piece of them. I am currently trying to solve two problems:

I have a Gigabyte GV-RX460WF2OC-4GD type card. I managed to find the faulty MOSfet (AON6414A) on it, which I replaced. The card starts up, but after about half a minute, the MOSfet in the same position will be shorted again. Is it possible that the PWM controller driving the MOSfet is faulty? I can easily measure the Gate with an oscilloscope during operation, if I see a difference with the other MOSFETs, does this not cause a problem?

Another more serious problem is that when removing a Saphire Nitro+ RX4708G MOSfet (IR3553), the REFIN footpad was damaged on the panel and apparently cannot be repaired. There are two other free non-soldered MOSfet slots on the card. Do you think that the currently unused MOSfet space can also be used by transferring the R-C-L components of the damaged part? There is no prohibition on these PWM pins in the controller, this can also be measured with an oscilloscope, does it give PWM control?

Since I'm still practicing SMD soldering and that's why I lost the micro-sized pad, what advice would you have for removing parts that are very difficult to solder with hot air? Even though I increased the air to 430 degrees, it was very difficult for the MOSFET to come down and the flux just smoked. What is the trick to easy hot air desoldering?

Thanks,

[harp]

Even though I increased the air to 430 degrees, it was very difficult for the MOSFET to come down and the flux just smoked. What is the trick to easy hot air desoldering?

Generaly, put card on preheater plate on about 120-150 degree celsius. When you can, touch a legs with fresh solder63/37... This will make desoldering easier because of smaller difference in temperature.

For videos chanell,
northwestrepair is all about vga repair in depth
Northridgefix is all about soldering and desoldering technique

[McWhitePink]

Can you post a picture?
usually even you lost the pad it should be still able to mount the part and wire it.

[McWhitePink]

hot plate is necessary for this case.

[Nooy]

Can you post a picture?
usually even you lost the pad it should be still able to mount the part and wire it.

Yes, i tried to take a picture
As I take a closer look at "2." he didn't even survive - but this is probably not a big problem, there are other legs with this function Could the next empty FET's place be used instead of the faulty one?

[McWhitePink]

Pin 2 in your picture should be GND. you can check it.