Asking for help in repairing atx power supply.

My boss tell me to fix  a 1u power supply, i've  tried and failed and got some questions.So beg for chings helping hands.Thx.

Target :
No brand 1U power supply X 1.

Symptom :
Once disassembled 2 output side 1000uF 10V capacitors were found big tummy and got replaced.Also 2 output side coils have burnt mark (Some wire turn black. As shown in photos).When 220V is connected, 5VSB -> 4.99V (Consider to normal ?) when tried shorting green and black wire to start up, That 2 coils start smoking ................ Immediately power off and dare not try again.
DSCF3773.jpg
2015-5-4 00:23

DSCF3777.jpg
2015-5-4 00:23

Question :
1. Are these type of coils specially made to each cow model? How can one get replacement ?
2. Anything to check before replacing the coils ( If i can get them) to prevent further damage ?

Beg for adviceThanks very much.

Coil will not fail by itself. There must be something shorted/failed.

Check those output rectifiers, which need to be removed from the board before measured. Or it may be easier to remove the main RF transformer than remove rectifiers.

Once the RF transformer is desoldered from the board, those rectifier can be measured on the board.

Good luck.

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Switching Transformer?

Check those output rectifiers, which need to be removed from the board before measured. Or it may be easier to remove the main RF transformer than remove rectifiers.

jwong852 發表於 2015-5-4 10:53

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最簡單方法,邊度出事,跟返O的線路,向上check
多數check返O的IC先,e.g diode 有無打穿,IC有無short circuit

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回覆 1# AMX-002
Don't attempt to repair anymore, the circuit board can be corroded by the leaked capacitor fluid and cause the short-circuit. The actual damage is much more than you can see.

USB has ±0.25 V tolerance for voltage, so 4.99V is normal.

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No brand transformers are usually not worth repairing

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