How to judge smps transformer

Please tell me how test the smps transformer and to troubleshoot it whether it is faulty or ok.

Dear Arun Sharma
Hello
Can you tell me that how much is the frequency of your smps , and it's power characteristics ? ( voltage / current). thus i can help you.
Best Wishes
Goldsmith

Hi,

Check this link, Testing SMPS Transformer Without Load
it might be useful.

Do not test it in circuit u may burn out switching transistor , or at-least reduce the primary ac volts to as low as u can get until u see pulses on transistor gate or base .
most ps work even at 50vac u can also add 100w lamp in series of primary and gradually increase the voltage.
make sure u don't have a short on secondary cause of rectifying bridge or diodes and/or load ect..ect..

Given that a transformer as wound can only suffer from two faults :- 1, winding open circuit - test with ohm meter, and 2, windings have a short circuit turn. The problem really is does this transformer suffer from a short circuit turn? A short circuit turn will reduce the inductances of all windings by some dramatic factor, like X 30 and as a side issue reduce the Q of each winding (more or less the same DC resistance, inductance goes down to 3% of what is was). So measure the inductance of any winding where you can figure out its rating and an approximation to the likely working frequency. One test for LOPT transformers was to connect the "cal" square wave from a scope to its primary and put a probe on its secondary. A LOPT with a shorted turn gave one pulse on the output while a good one gives perhaps 50 cycles of a ringing waveform - could work on SMPS transformers?
Frank