I just completed the repair of a 53UWX10BA yesterday. I purchased the Hitachi kit(JT22052) from our normal supplier. I pulled the convergance board and removed the STK392-110 IC's that were there. After I removed the IC's, I then checked the resistors already soldered into the board. They were all good*. I installed the new STK394-160E IC's, checked my work, then installed the board. Using a digital picture from my cellphone, I dressed the cabling as it was before disassembly. I applied power and signal through the component inputs and was greeted with picture and sound. The convergance was off a bit but I wanted to let it "cook" a bit before I ran the DCAM procedure on it. After about 1/2 hr, I stepped back about 10-12 feet and looked at the screen. What I saw kinda blew my mind. From the center of the screen going to the right...I had perfect picture! Zero, I mean no distortion or convergance problem at all. But, from the center of the screen going to the left...completely different story! All 3 colors divulged by almost 2" at the far left edge of the screen! Tried running the Magic Focus and it cleared up by only a little.
"All the resistors were good*." As in none were charred or open.
As I stared at the distorted screen....that came back to me. The resistors used in the circuit are supposed to be 5% tolerance. I flashed back on when I checked the resistors. The 1.5 ohm measured 1.6 ohm and so forth. All the resistors were within .1-.2 of what they should be.......COLD! .2 ohms difference on a 1.5 ohm resistor comes out to be right at 7.5%....out of tolerance!
I powered off the set and again removed the board, then changed all the resistors, then installed it again, keeping the same cable arrangement as before. Crossed my fingers and powered it up again. Once again was greeted with picture and sound, but..now I had just a small difference in the convergance. I used a laser thermometer we have at the shop to check how hot the new IC's were getting. After about 1/2 hour they were stable at 85 degrees C. I held my breath and pushed the Magic Focus button..... it took about 20 seconds for it to run through the routine, but when it was done...I had perfect picture...all the way across! I let it run for about 3 hours to make sure it was stable and had to make no more adjustments to it. Going to have another happy customer because they wanted it back for the New Year's Games.
This episode taught me a lesson...if you have new parts...USE THEM! Trying to save myself some time resulted in my having to in effect, do the job twice!! Low ohm resistors being .1-.2 ohms off what they're banded require replacement. Luckily, I didn't damage the new IC's in my haste to get the job done.
Lesson learned!!:sweat: