I am hoping someone here may be able to help me with solving an intermittent fault with our family TV It is a Phillips 21PT2012 / 79R and has what I think is the serial number of BZ000231 723707 on the back cover. The fault manifests itself as sudden loss of all picture, and light from the screen and loss of sound at the same time, anywhere from 5 seconds to a few minutes from switch on. This started a week or so ago, and a turn off seemed to fix it, and now it will not run longer than a minute or so without dying. It seems like the HT supply drops out suddenly, but as I understand it the power supply rails for all the circuitry on this type of appliance may very well all come from one switching supply, and a fault there could wipe out everything? I have a reasonable understanding of electronics, and a good Fluke multimeter, but no cct. diagram, and no experience with TVs. Any suggestions? I think that the set is about 4 years old, and I guess it must be some component that is built to a commercial standard starting to break down, but I was hoping that there may be hope rather than junking it? Thanks for any assistance.