RE: Help Me WaterProof Hobbywing Xerun 150amp Sensored System
No problem there, Rare. It's the components that actually make contact with the component-side of the heat-sink that matter. (You're asking about the little black chips, right?) Since you DO have the heat-sink off, you could CAREFULLY apply Liquid Tape (using a small art paint brush, not the gigantic one that comes in the bottle) to seal that side of the PCB, being careful not to get ANY on those components that contact the heat-sink. But Once you install the heat-sink, I would still seal around its edges with Liquid Tape and that small brush, to keep moisture out from under tghe heat sink. BTW, you don't need to use one of those self-stick heat-sink pads AND the Arctic Silver, just one or the other. The important thing is, is to make sure the heat-sink is firmly attached and is not going to come loose.
I come from a computer background, so I'm familiar with how to properly use a heat-sink. In your pictures, since you already had the heat-sink off, I could not tell how it attaches. Was it, literally, stuck-on with that heat-transfer tape? Or was there also a heat-sink clamp over the top (or thru) the heat-sink, holding it to the PCB or case? That heat-trans tape sticks those heat-sinks on pretty good. The Arctic Silver stuff I used at work was not an adhesive and we used heat-sink clamps to hold the sink to the motherboard.
Rob