This repair was for an RCA model L42WD22YX6 42" LCD television. There are very few parts available for this tv after it goes out of warranty, the manufacturer expects you to put it in the dumpster and buy a new one! The symptom was “Has sound, no picture”. I was quickly able to determine that the power supply was being turned on by the main board and that all of the voltages there appeared good. After a short investigation, I found the main fuse on the slave inverter open and a 2 ohm short across the filter caps. I removed shorted MOSFET transistors, SQ8 & SQ9 (FDD8447L) but still had the short across the filters. The IC SU1 (BD9897FS) was also shorted. The 2 filter caps were slightly puffy at the top.
Parts replaced to repair the set were: IC SU1 = BD9897FS SQ8 & SQ9 = FDD8447L 470UF/35V x 2 SF2 = 10 AMP SM FUSE
The pictures show: 1. This is how I remove those pesky MOSFETs. You are seeing more than $900.00 worth of soldering equipment in action, and that’s what it takes to remove those parts without damaging the board. This picture shows a board that is not in this set, but is a good shot of me at work!
2. The inverter board with the bad semiconductors removed and ready for the new parts to be installed.
3. New parts installed and the board ready to go back in the set.
4. The repaired set up and running. Sure do need to clean that mirror! I was not able to verify that this set had sound before the repair and now I can see why - it was on the DVD input!
The board repaired is sold only as part of the 4A-LCD42T-LG6 LCD panel, which retails for 498.21 and is no longer available at any price.
This is why Tv Tech Electronics specializes in component level repair! Click any picture to see a full sized view.