I have the classic issue with an older ducted Fujitsu unit. The SMPS area of the inverter board has failed.

In doing so, a brand new fan motor has been killed (the diode between ground pin4 and 15v pin 5 , ie the black and white wires on the fan motor lead has shorted).

I removed the 3 screws at the bottom and opened the unit to expose the PCB inside. Sure enough the diode at the start is dead.

Just wondering if anyone has a schematic diagram for these little boards inside the fan motors?

Feel that the diode could be replaced, and it will be back in action. Would like to check the caps, but don’t have any reference for what value they should be.

Also, if anyone has identified why the inverter board SMPS fails, I’d like to know that as well. I replaced the Q1 transistor and zener diode. But it made a squeel noise and died again within a few minutes.

Has to be either the JPZ transformer in the middle, or the caps. I tested all the caps, but apparently they still maybe faulty even if they test to spec.