Dear Friends I had this rectifier, and unfortunately I haven't the schematic .
when I plug it the.
1- The unit gives me an alarm as shown in the photos OVP Trip
2- I tested the VCC on PWM uc1842 there are no volts .
3- Also the LM7812 there is no Volts which have to supply the rely by 12v.
4- I checked all mosfet and diodes Schottky there is no shorts .
5- I removed the two optocouplers to test , When I plugged it there is volts suppression it is behind the red circle X photo number 4 it has blown immediately.

can anyone please explain to me why it is blown?
and what the reason for OVP.
my dear friends kindly anyone have the schematic of this rectifier I tried to search for it but I failed

 

Did you plug in without the optocouplers? Why? Optocouplers provide feedback from the output to the SMPS power switch. Without them, the PSU runs away and blows up, I think , from not looking at the schematic.

 

Did you plug in without the optocouplers? Why? Optocouplers provide feedback from the output to the SMPS power switch. Without them, the PSU runs away and blows up, I think , from not looking at the schematic.

Thanks sir ...my question the Ic UC1842 not working because there is no VCC on pin 7 ...so the MOSFET is already not bulied magnetic on the flyback transformer so there are no powers in the secondary portion ...for that I was wondering why the voltage suppression blown.
so kindly can you explain to me why because I miss this point

 

UC1842 uses a startup voltage from the HT supply, usually via a resistor, then it has it's own supply from the transformer via a separate winding. Check the resistor supply voltage voltage first.

 

UC1842 uses a startup voltage from the HT supply, usually via a resistor, then it has it's own supply from the transformer via a separate winding. Check the resistor supply voltage voltage first.

OK sir thanks I will.
Best regards