I see your flash mark on the HS.
The fact that you had a constant 170v and the large Cap, would indicate is most likely a PWM drive.
You may have to do a bit of reverse-engineering.
It obviously points to one of the solid state components on the heatsink, I would unscrew the fastening screws and remove the HS components one at a time and identify by part number, download the spec sheet, and test them for shorts between pins.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.