while not a huge fan of Panasonic myself I got involved with a PT-50LC13 at my friend's request. The TV would consume lamps on the regular basis but the recent lamp replacement has failed to fix it. My friend Googled up this forum and this ballast thread and forwarded to me which has saved me a lot of troubleshooting time and aggravation. I'd like to thank the folks that have contributed valuable technical information to this thread and in return I'd be glad to post my own repair results in hopes that they would help somebody to save time and money.
As most everyone in this thread I have installed all of the components that came in the LSUC0022 kit except for one - the "transistor". The end result - a television set that has started from a "quarter turn" and at the moment is cheerfully running my son's cartoons since I don't have cable service in the garage.
I'll describe all of the components that came in the kit in the reverse order in my version of the "best of" show.
6. F0CAH104A001 (position C1330 on the PCB)
It's a metal film ceramic capacitor, 100,000pF.
IME unlike the drying out in time electrolytic capacitors, I have never ever seen a ceramic one just "go bad". Sure, they do explode once in a while (the old circa 1980s era AKAI liquid cooled amplifiers come to mind) and you have to scrape the black soot off the PCB while replacing its remains, but if it looks OK, then it is OK. I replaced it anyway "just because".
5. B1DEGQ00004 (positions Q1306,7,8,9 on the PCB)
It's not just a "transistor", it's a FET. I wonder why everybody's talking about four of those (including the parts list that came with the kit). In my case there were only three on the board. The fourth one was a diode. Sure all four have identical T220 cases, but only three had the proper three legs coming out of them. The fourth one had just two legs and was denoted by a diode symbol on the silkscreen.
Anyway, I didn't replace one of the three arbitrarily because it just made no sense as many participants have rightfully pointed out before. And since they were FETs and not regular bipolar transistors I had no way of testing them. Besides, I am extremely leery of testing the very sensitive to static electricity FETs since in the past I blew more of those than I am willing to admit. Sure the FETs have come a long way since 1970s when you couldn't touch the damn thing with bare hands and had to wrap up all three legs in Aluminium foil, but I elected not to touch it unless the repair would fail and I absolutely had to replace all three of those.
4. LSSF0013B50T (position F1301 on the PCB)
It's a fuse.
I did test it with the multimeter for the continuity and it checked fine, but I elected to replace it anyway "just because".
3. MA2Q73600L (position D1301 on the PCB)
It's a SMD diode.
I did test the old one with the multimeter prior to removal and it tested fine, but I replaced it anyway "just because".
2. D1F5100E0002 (position R1305 on the PCB)
It's a 10 Ohm ceramic power resistor.
Just like with ceramic capacitors, I have never ever seen a resistor just "go bad". Sure, they do burn out once in a while and you have to scrape the black soot off the PCB while replacing its remains, but if it looks OK, then it is OK. I replaced it anyway "just because".
and the winner i-i-i-i-i-s...
1. B2ZAZ0000020 (position D1315 on the PCB)
It's a power diode.
Several posters have mentioned above that they had found this particular component burnt and melted. Mine looked OK. However, in the P-N junction testing mode my multimeter showed infinity in both directions. Just for the hell of it I also tested it with the ohmmeter. It did show the expected infinity in the reverse direction but showed the unexpected ~1.2M in the forward direction. The new one passed the diode test normally and showed the expected several hundred kilo-ohms in the forward direction. This diode was clearly the culprit of the problem.
The part number search (KIV237 - for the old one, KIV269 - for the new one) did not yield any results but my gut tells me that this is a plain vanilla power rectifier which should cost less than a dollar from Digi-Key, Mouser or your other favourite electronic component supply house. Then again, the 5 bux + change that Panasonic wants for it, or better yet 4 bux from partstore.com is still a pretty good deal all things considered.