replacing fet's in a bk9920
 

i had one fet with a little burn on it, and i want to replace it. i've pulled the esc apart, but haven't gotten the numbers off the fets yet. where would one locate fets at, and also i notice even though the two boards appear to have the same sized fet's, they look like they have different numbers on them. i accidently pulled off two extra fet's getting the heat sink off:surprised:, so i'll need a total of three. if anybody wants to save me some time searching, let me know which fet's the bk9920's use and where they are that would be great.

one more thing, how do you get that white poo off of everything, and what is it so i can put it back.

Digi Key should have the Fets. The white poo stuff is silicone heat grease hard stuff to remove but must be used to help transfer the heat to the heat sink.

is that the same as thermal paste? if so thats great, we have some at work for our thermal probes.

I have a BK 2095 micro here, it didn't smoke, just quit working, you can have it for a small fee, plus pay a little for shipping.....and it has quite a few fets on it as well.....

White "poo"??? :lol:

Anyway, it's probably thermal adhesive, not thermal paste. Paste doesn't have any adhesive properties and comes off easily. Adhesive is a little more difficult to remove, but it's just a matter of gently scraping it off with a flat-tipped Xacto blade and then cleaning with denatured alcohol or something like that.

Arctic Silver makes two types of adhesives (or epoxies). Arctic Alumina is the stuff you want to use because it doesn't have the traces of silver that their Silver Adhesive does.

I think it this stuff the same stuff used on your computers CPU for heat transfer to your fan.

http://zero-friction.com/siliconegrease.aspx

Similar. A lot of people use Arctic Silver or silver based thermal grease/paste on their CPU. Be careful because the silver based stuff has a little capacitance which isn't great.

Also, make sure you use epoxy. And if you ever need to take it off again, hit it with a heatgun first ;)

do you know if it uses the same fets, and pm me a price

ok, i have no idea how to read these fet's.

i found the manufacturer IR international rectifier.
there are 3 lines of numbers. which do i use to cross reference? only google/yahoo hits i got where the last line which is f7413, but i get alot of results and nothing else matches anything.

digikey turns up quite a few results. Don't know which ones you need though. maybe the other numbers will help your narrow it down?

theres a 9920 on ebay

I've found this datasheet search tool to be invaluable. IMO, if anyone will ever even think about looking at electronic component specs, this should be in their internet favorites.