Inside the Quark 125, pics.

[BrianG]

That is interesting. I took mine apart but the FETs were stuck pretty good to the case and I didn't want to break any, so I never got it apart that much. Looks to be well constructed. Is that an Aluminum heat spreader between the PCBs? From the looks of it, there are 12 FET IC's per phase (top and bottom of the PCB), not too bad. Can you read the part number on one of the FETs? I'd like to look up their datasheet.

Of course, anything you do to mount it differently will probably void the warranty, but I'm sure you knew that. You could mount the assembly in a better heatsink like this (from here) inside the channel, and then fabricate some kind of enclosure to cover the other parts of the ESC. NOTE: Do NOT use thermal epoxy like normal Arctic Silver. The paste will squeeze out when you press the FETs on the heatsink and the silver particles may contact the FET leads and/or PCB traces and cause problems. Even if you don't get a direct short circuit, the particles can introduce capacitance. Make sure whatever thermal bonding agent you use is electrically insulative, yet thermally conductive. You can use this instead - same company, different blend.

Also, when I removed the top plate (where the LEDs and button are), I accidentally ripped off a surface mount capacitor. I was able to resolder it, but it was a pain due to the size. You might want to check to make sure you didn't do the same. I can tell if you did or not if you could post a picture of the top board if you want.