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Led light system faulty smpsu

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  • Led light system faulty smpsu

    I have an issue with a 32v psu for a led light system.
    Basically 2 screws came loose and touched the board. Failed mid show. No blown fuse or any burnt component.
    So I changed the uc3842 and it came up and provided 32v found a 470r supply resistor to the opto coupler burning up. Changed the opto and WL431 ic all working.
    Connected back up psu is pulsing. With the other two boards connected. I don't have a bench psu. So put together a test one. Led system working ok
    So it's most definitely psu at fault
    It seems to be not able to supply enough current to the 2 boards.
    Changed / swapped out
    secondary diode
    Secondary caps
    Primary caps
    Changed the uc3842 2nd time
    Checked all components on board can find nothing wrong. All in spec.

    There is a preset pot on secondary in the opto circuit
    I have loaded up the output 32v with a some resistors and if I go down to about 39 ohms 5watt. The psu will start pulsing. ( 6v-10v)Anything above that the psu keeps on pushing out 32v. Can't find a schematic.

    If anyone can shed some light I would be grateful