Any way to repair a bad ESC?

I’ve just got a pre-built with one of these junky things in it:

http://www.diyeboard.com/v11-dual-hub-motors-sine-wave-foc-esc-speed-controller-p-608.html

One motor works good, the other behaves as though it has a short in the coils when its connected to the ESC.

Been using it this whole year just with one of the motors disconnected, but its kinda gutless with only a single working motor and I’d be nice to address.

I could just replace the whole unit, but I’m not sure this pre-built is worth all that when it might just be as simple as some replacement components on the board.

Judging by the behavior, I’d think it would be the high voltage motor facing circuity, but I’m not sure how I might narrow down which components could be bad. Visually everything looks good, and smells normal.

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Just get a new controller for 50

$60, if you include shipping.
Which is about $30 more than I’d like to pay to get this thing working again.

Anyway, I’m pretty sure I’ve identified the bad mosfet.
After discharging the caps, I just tested continuity across all the mosfets to see if there were any discrepancies between the working half, and the broken half.

I have located a broken mosfet, I de-soldered the leads, and even disconnected from everything all the leads show continuity with each other, which I’m pretty sure should never happen on a good transistor.

Also with it disconnected the motor no longer acts as though it has a short across its leads and can spin freely.

So now the question is… Can I desolder the mosfet head sink from the board? I had to stick the whole board in the oven at 250 just to get enough heat with my iron to get the leads off. Getting the whole mosfet off will likely require that and a heat gun, or worse.

The second question is, Is that the only faulty part, or will a replacement mosfet just burn out the second I put it on?

And I suppose the last question is, can I find a replacement equivalent mosfet for under $5?

Datasheet for the mosfet for any who might be curious.
https://datasheet4u.com/datasheet-pdf-file/1148507/SI-TECH/S68N08S/1

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Might have a spare if you want for $40

Might take you up on that after I finish breaking this one.

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I also have a spare but shipping from Canada might kill you

May have died just thinking about it.

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