Hello,
I have a 52 inch Mitsubishi projection tv that 5 years old. Do manufacturers design these tvs to fail after about 5 years by the leakage of picture tube collant?
I was watching tv when turned itself off. I found an oily substance next the filter caps on the switching power supply. My initial thought was that the cap had leaked and shorted leading to the loss of the 12v standby supply. I fixed the problem, the tv worked for about 4 days and again failed. This time I found that my xray protection circuit had triggered the tv to turn off. I traced out the problem to the microprocessor input. The problem was a printed circuit land had been destroyed by an oily like drip from somewhere. I repaired it and cleaned the pc board with 91% isopropal alcohol. The video circuits and receiver works but my tv no longer receives a broadcast. It only works with my vcr. I notice that my aft is standing steady. My schematics dont describe how to test or what to look for in this part of the circut. I read some books on tv repair telling me that it works like a phase lock loop. Can anyone suggest what I can try? I have also contacted the manufacturer to discuss what they can do for me. It seems that they know that the tubes can leak corrosive collant. So, why didnt they provide a shield on the boards? Why should I have to pay for this?

yeah they know the tubes leak, all the projection sets i have seen have a drip pan inside to catch the coolant, but those pans arn't worth a sh--. they don't catch it all, and then ruin the chassis sometimes. i througly clean the boards with cans of spray contact cleaner, & then blow out with compressed air.