A Dead LCD brought back to life. Model: LG32LF15R
A friend of mine who works in a company in my area brought his TV for repair and as he explained the problem I realized either it is a power supply issue or main board issue since I did not see any stand by light coming on. It was completely dead.
As I took the back cover off and scanned the area with my naked eye, I could not see any marks or any bulging in any of the capacitors.
I checked the fuse but it was intact.
As I checked the main capacitors, I was getting about 350 DC volts there which indicate from this point back it was in perfect conditions. I turned the TV off and wanted to make sure the capacitors were discharged; they were still holding charge which is an indicator that something is open along the way. I noticed there was a fuse there next to these capacitors; I checked that fuse (after discharging the capacitors of course), the fuse was open.
The logical thing here is to look for the cause of this open fuse and soon enough I was able to find it. It was a Mosfet nearby and as I took it out, it was shorted. The part number is: P9NK65ZFP.
I already have the exact part number in my shop and I installed it on board but I did not power it on because I want to make sure nothing else is shorted.
Click on the photo above to access the datasheet
Sure enough, as I traced the pins of the Mosfet I was guided to this area of the board. I found two SMD resistors open, one was 10 ohms and 33 ohms and since these were open, I am almost sure the IC is gone too. The IC: Have these writings on it 1207A and the low reading: PFMW. This IC was so hard to find but when I called my friend who is also a technician he suggested to replace the whole board but when I asked him if he has this IC he answered yes.
I was thinking of replacing these open parts then if that did not work then I will consider changing the whole board.
As I replaced the two open resistors, the Mosfet, the IC and the fuse I added a light bulb to the main fuse and powered up the TV and I could see the stand by coming on.
As I took the light bulb off and put back the actual fuse and powered up the TV, it came on and as you can see connected a source to it. It was working just fine.
This article was prepared for you by Waleed Rishmawi, one of our ‘Master Authors’ and currently working in the Bethlehem area of Palestine repairing electrical and electronic equipment.
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Note: You can check his previous repair articles in the link below: