Trial and error replacement only works if you are lucky enough to hit on the right component(s)
Initially when these things blow up they can take many other parts with them.
You need to do some detective work to find the bad bits.
Output devices blown?
Replace all six, or at least pairs of devices. If one went short, then the other one in the leg supplied the excessive current, and can't be trusted.
The zener diodes across the gates of the IGBTs often get destroyed. That becomes their protective function at smoke time. :banana:
U201 switchmode supply is the first section to get working properly, and it must be run from mains voltage.
This is a common failure after a blowup - usually caused by a rogue wire to chassis that started the whole episode.
Doing any of this testing without an isolating transformer is asking for trouble.
The exception to this is tacking on a few leds and resistors then switching on to see if they light.
The slightest slip with a meter probe can cause smokey (or more) problems due to the vast potential differences on adjacent areas of the PCB.
Really dumb design is well proven as evidence by the difficulty doing repairs.
Once you've socketed the drivers it is all a bit easier.
The drivers are fairly easy to test on a low voltage supply.
1. Does the relay come on. Then see if your leds work below.If the EStop switch is used on a regular basis the relay contacts eventually fail. Every tiome you reset it the current surge kills them.
Only use in an emergency. Power off. Reset the EStop, then the relay will survive.
2. The low voltage section ,must be fully operational. Put a led and 470 ohm resistor hall sensor supply pins 1 and 2 of CN101.
If this does not light up then the switchmode supply needs attention.
3. The low voltage section ,must be fully operational. Put a led and 470 ohm resistor at the output of each regulator.sensor supply.
EACH of these supplies are isolated from one another.
4. Once the supply is working, verify that the hall sensor signals are OK. Did you check them?
5. Hall sensors OK.
6. Now look to get the output sections working.
Super X3. 3600rpm. Sheridan 6"x24" Lathe + more. Three ways to fix things: The right way, the other way, and maybe your way, which is possibly a faster wrong way.