Hi guys,
Is there any easy way to test newer design SMPS IC that has all kind of over voltage, over current limit ? e.g. : M51995AFP.
I have a power supply using this IC with no output. Fuse is good, secondary diode are good, switchers are good. Supply will trip ELCB if powered on with full AC input (>100VAC), ramping input up shows that the PSU suddenly draw high current at about 80VAC (about 2-3A) from mains, and there is trkk trkkk sound for half a second or less and after that it does not pull current anymore. Increasing VAC beyond 100V is fine this way and will not trip ELCB as there is no large current pull after this. Main Electrolytic charge up to about 385V (there is PFC IC in this supply)
All I can think now is the main M51995AFP IC not working correctly. There is no pulse output driving the switcher from this IC. I don't have a new parts for this, and replacing this IC from a salvaged board does not solve the problem (it could also be that the salvaged board has problem with the IC).
Will update with pictures and model number once I get back to lab...
Is there any easy way to test newer design SMPS IC that has all kind of over voltage, over current limit ? e.g. : M51995AFP.
I have a power supply using this IC with no output. Fuse is good, secondary diode are good, switchers are good. Supply will trip ELCB if powered on with full AC input (>100VAC), ramping input up shows that the PSU suddenly draw high current at about 80VAC (about 2-3A) from mains, and there is trkk trkkk sound for half a second or less and after that it does not pull current anymore. Increasing VAC beyond 100V is fine this way and will not trip ELCB as there is no large current pull after this. Main Electrolytic charge up to about 385V (there is PFC IC in this supply)
All I can think now is the main M51995AFP IC not working correctly. There is no pulse output driving the switcher from this IC. I don't have a new parts for this, and replacing this IC from a salvaged board does not solve the problem (it could also be that the salvaged board has problem with the IC).
Will update with pictures and model number once I get back to lab...
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