I'm attempting to fix an SMPS for a sewing machine that is having all of its outputs voltages a third from what's expected.
I've replaced all electrolytic capacitors and nothing seems to be producing heat that would indicate a short circuit, so I'm thinking it might be its feedback loop. This board utilizes the module MR4030 to control the Energy transferred from primary to the secondary but I didn't see any TL431 and I suspect it's the 4A 0F3 that I don't know about but I couldn't find what it is to consider to replace it.
There's another component as well that I don't recognize shown below. Do you recognize it?
Full board (the model of this board is HSV-MC122072):
Looking at the image of the whole circuit below the two big blue capacitors on the "small" heat sink is the bridge diode and down under it is the circuit that controls the motor of the sewing machine, which it does through a relay and other stuff. On the left of the two big blue capacitors with the bigger heat sink is the MR4030 which has the Mosfet that does the switching, then more on the left is the transformer to the Secondary part of the circuit. Right under the MR4030 has an Optocoupler and a bit more down to the left is the component in question what I think it's the shunt regulator.
And here is a look underneath.