I have a little problem repairing my LCD power supply (22 inch old monitor). I already change the damaged capacitors (one is good but i change all 5 anyway, last image bottom right).
The problem didn't solved then i continue searching why don't turn on the monitor.
Now i find a component that appears to be bad, it looks like a diode, but the symbol is for inductor if my memory dont fail.
It's completely black, and i cant figure what is it. I tested and is in short circuit without any resistance.
Somebody know what is it?
Anyway the PSU is this one: YP1504PG 6871TPT318G 207.01.03 REV 1.3
I checked the voltage in the output and must be 2x 5v and 2x 15v but no one give current. Anyway the monitor dont start, but the filter fills and remains with about 340V (the two at bottom left).
Thankyou in advance
Best Answer
It looks like the supply is not running. This could be due to a defective IGBT or Mosfet.(Q101?). This kind of failure is not uncommon in monitor and tv sets.
I do not know if you had a blow fuse. If that has been the case than you need to replace the rectifier. (The flat in the left bottom corner). The main capacitors (68uF 450V) Select new ones with 630V. Q101 also. Most probably a component with a voltage limit of 450 V. Replace that with an equivalent but now 630V.
A rectifier could get damaged in case of a short circuit. Remeber you can only test for errors not for upcomming errors.
Replacing parts with higher voltage increases the error margin and forms a better protection against spikes.
Once you are there it could be that the system is running and hopefully not more is defective.
the bead inductor should be ok. Even if shorted out the inverter should run