I have this Huntkey HK340-72FP PC SMPS where I am facing a strange problem where the SMPS shuts down when the load on any of its 12v output rails goes above 2 amps while the rating of each 12v rail is above 10amps capable.
I have checked the following:
1. All output caps are OK, and all output rails read correct voltages at no load
2. All output diodes are OK
3. NTC is ok
4. Hi voltage cap on input correctly reads 150uF on LCR meter per the spec, also the bridge rectifier is OK
5. No short in main switching MOSFET
6. All other components visually look OK, no signs of burns or anything
7. Standby 5V supply is good, which is why also the SMPS is able to switch ON when green wire (PS_ON) is shorted to ground
When I connect let's say a 5 amp load on any of the output 12 v rail, it shuts, and it works fine till a 2 amp load with a stable 12v reading.
Surprisingly the SMPS doesn't turn off if I directly connect the load before the rectification of the 12v rail which is directly on the secondary winding of the HI-POT transformer.
What could be the issue? any help is appreciated.
I have checked the following:
1. All output caps are OK, and all output rails read correct voltages at no load
2. All output diodes are OK
3. NTC is ok
4. Hi voltage cap on input correctly reads 150uF on LCR meter per the spec, also the bridge rectifier is OK
5. No short in main switching MOSFET
6. All other components visually look OK, no signs of burns or anything
7. Standby 5V supply is good, which is why also the SMPS is able to switch ON when green wire (PS_ON) is shorted to ground
When I connect let's say a 5 amp load on any of the output 12 v rail, it shuts, and it works fine till a 2 amp load with a stable 12v reading.
Surprisingly the SMPS doesn't turn off if I directly connect the load before the rectification of the 12v rail which is directly on the secondary winding of the HI-POT transformer.
What could be the issue? any help is appreciated.
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