First, thanks for this forum and your effort to help people. I'm sure many would junk their old sets and buy a new one faced with an expensive repair. We are looking to replace ours with an LCD when the prices come down, in the mean time our old set should be good for a few more years.
We have a Mits WS65819 bought new about seven years ago. We had it professionally calibrated four years ago. About two months ago it started going out of convergence calibration after the set was on for a few minutes. It didn’t creep out of adjustment, it was digital – perfect or way off. At first a simple power off and on would bring it back. As time went on it took less time to develop the problem and more time before it could be "corrected". Sometimes it would correct itself.
These symptoms told me there were probably bad solder joints, but where? A search on the internet led me to several forums where my exact problem was being discussed. So I knew it was the convergence IC's. I also read that it's not wise to just repair damaged solder joints -- if the chips finally do fail they could take other components with them. I decided to replace the IC's. I felt I would find no bad resistors or fuses since the TV could operate normally for long periods of time once everything was up to temperature.
This is where I made a mistake. I hadn't found this forum yet, but the common wisdom was to buy Sanyo chips from a reliable vendor. Instead, I saved a few bucks and bought from Bluestar International. I also bought some 5A pico fuses just in case. Good thing I did.
I removed the main board and found ring cracks around most of the IC's pins. I was sure they were the cause of the in and out convergence problem. Since I had the new parts and I was reluctant to just re-flow the joints, I removed the old chips, cleaned everything up and inspected the board. Everything else looked good, no coolant leaks, burned resistors, etc. I carefully soldered in the new IC's and other than having a little trouble wetting the pins, it went pretty well. I reinstalled everything and fired it up. Rats!
The set powered up for two seconds, then shut off. I tried it again -- same result. Out comes the board and I inspect my work with a magnifier, not just reading glasses. I found no bridged joints, only a few joints that looked less than perfect. I carefully re-flowed those and checked the fuses. One was blown and I replaced it. Back in with the board, everything connected and checked. Fire it up -- same result, on for two seconds, then shut down. I stop working on it. I put the covers on to keep the cats out and I thought about what it could be that caused a problem beyond what I had to begin with. I figured I either trashed the board by working too long trying to wet those pins or I had bad parts. Trusting my soldering more than my cheap IC's, I ordered new IC's from MCM and waited. I got the parts and pulled the board. I went through the same removal and inspection process as I had done the week before. The board looked fine but that same fuse was blown again (no surprise since I didn't really "fix" anything since the first time it blew).
I did tin the pins on the new IC's before installation and that was a wise move. I believe they were tinned with lead-free solder and having them out and wiped with flux made it very easy to get a good base of solder on the pins. I did the installation as before, replaced the fuse and re-installed the board. This was going to be the last time I did this, I was going to call for help if this didn't work. Turn on the TV and wait two seconds, three seconds, four five six,,, It works! Bad Parts!! I knew it!!!
I got good advice and didn't heed it. My bad. Buy from a known good source. It's not the money, it's the lost time and the potential to damage what wasn't damaged to begin with. To their credit, Bluestar was glad I contacted them about my experience and apologized for the problems. They told me they had not had any reports of problems and mine was likely an isolated case. They told me to expect a full refund by tomorrow.
So, my masterfully calibrated TV is working but it's obviously out of calibration, it looked out of focus but I hadn’t looked at the convergence yet. I never attempted to adjust out my original problem but I wasn't surprised it had changed with the new parts. I did about 10 minutes worth of adjustments with the user level convergence menu and got it much better. I know the TV wasn't warmed up fully (maybe 30 minutes) and the parts were brand new. It's been used about 20 hours now and I will do another round of adjustments after a two hour warm up. I think it will be fine after that.
Would you expect anything else to be off with the new parts? I noticed some distortion in the very lower left corner but I need to do a full look with the calibration disk to see if anything else is visible. Could it be that that corner was sacrificed for the rest of the adjustments during calibration?
Thanks again lcaillo for this great service. .........Bill