I’m a amateur hack at best. Mr. P helped me last year with the same problem. I ordered new mosfets, only a couple of bucks. I used my old cheap soldering iron, a pair of wire cutters and a few toothpicks. Took maybe 30 minutes.
What worked for me.
1) cut off the old mosfet from the top. (Snip the little metal leg just underneath the black part)
2) heat the connection from the back while pushing from the top with a toothpick. The little piece will just pop out.
3) When all three are removed slide a new mosfet in from the top and and add a tiny drop of solder
4) That’s it!
Thanks again Mr.P!