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Suggestion On Repairing Power Supply

By Jestine Yong on July 18, 2013

I need your help to solve this failure of DENSEI LAMBDA power supply model JWT100-522/A, in the first time it was the fuse burned then i check the board i found KS2601 defective, since i didn’t find the original one i replaced it by IRFP450; but when i supply it, i put the lamp to avoid that transistor mosfet to get defective,and the bulb 100W it is not steady it vary low high, in this moment i measure the 3voltages outputs there is for example 5v but it falls to 0 then it come back like bulb lighting, so could you help me in what area i should check ? and following your experience what is the component who is still defect, one remark one of 3 outputs(V1 G1) it has 37.5OHMS in diode test is 0.036 but the others outputs has 0.479V.

Answer:

Usually when any FET shorted or have problem the related circuit surely will have problem. This means you may need to track from the Gate, drain and source pin until you could find the bad components. if there is no bad components then you may need to direct replace the power ic that supply the gate signal to the FET. If it still the same then i suggest that you connect the original load and with the fuse and turn it on. Sometimes a power supply really need full current (bulb will limit current) and full load to work properly but in this case you may have to take the risk.

As for diode I don’t trust digital meter result. I would use analogue meter set to x 10 k ohm to test the diode off board. A good one should have one reading unless if it is a Schottky diode. A Schottky diode will have one full reading and another result would be half or less than half reading.

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hojjat

July 23, 2013 at 5:41 am

Hi I want to know that how a man can repair LED & LCD panels

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- Jestine Yong
  
  July 23, 2013 at 7:34 pm
  
  HI Hojjat,
  
  If the screen is cracked or have one line it can't be repaired. Sorry no info about ACA9K.
  
  Jestine
  
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