Please explian probable cause to rectify problem of faint video on a Philips projection TV model#50P8341A all pictue setting adjusted

Was this sudden, or was this gradual? Is this on all video inputs? Have you tried other connections/devices?

Well on mine this happened over a period

I've been researching this problem myself and the majority of opinions are that the CRT coolant needs changed. It becomes cloudy over time resulting in a dull, blurred image. Kits are available to do it yourself for about $70.