Replacing FETs

[spleenharvester]

What wattage soldering iron should be used for replacing SOP8 FETs?

Every single one I've tried to replace with my 40W or 15W irons has just resulted in lifted pads. I've always had to heatgun it, but obviously that comes with its risks.

The way I do it is, flux all the legs, slide a sewing needle under one side, and melt the solder - lifting all the legs on that side. One of them always pulls the PCB off with it!

Cheers

[mariushm]

Re: Replacing FETs

Liquid flux, add solder, liquid flux, solder wick, put solder iron on solder wick and suck solder in the wick. DO NOT DRAG the solder wick or drag the solder iron tip on the wick.

A 60w iron will be fine. Maybe even lower wattage will work fine.

[momaka]

Re: Replacing FETs

It's much easier if you use 2 irons at the same time. If one of them is temperature controlled soldering station, even better. And if you have 2 temp-controlled soldering stations, you can desolder almost anything you want.

The method is simple. Flux both sides of the MOSFET, add plenty of solder so that all of the pins are covered on each side. Add a bit more flux again. Then use the two irons to heat the MOSFET from both sides and lift or slide away the MOSFET. It's nearly impossible to damage the board this way. The only thing to watch out for is if you slide the MOSFET, make sure not to slide it into nearby SMD components, because they get desoldered too. Normally what I do before removing a MOSFET is take a picture of the board where it is located if there are a lot of small SMD components. That way, if one gets desoldered and lost, I can replace it. So far, that hasn't happened, though.

[dj_ricoh]

Re: Replacing FETs

It's much easier if you use 2 irons at the same time.

What? 2? one its ok but it needs to be good and a large tip.
whats wrong with hot air ?if got a crap air gun that has a ventilator near the resistance yes! thats crap and you won`t be able to work with.
With compressor in the station; thats a good station. starting from gordak... how about that even they got a good soldering iron on that station with removable tip ... my first station.

[momaka]

Re: Replacing FETs

I have hot air too. But I still prefer 2 irons since it's much faster and if there are capacitors around the MOSFETs, I don't have to remove the caps.

[klangsotan]

Re: Replacing FETs

hai sir i have problem mosfet similarly where can i find link about that ?