Video Asylum

Posted by cfraser (A) on January 20, 2002 at 13:05:08

In Reply to: Re: Need help with system setup (Tivo, VCR, DVD, OLD tv) posted by sjarvis on January 19, 2002 at 20:29:21:

It still sounds like a video-AGC amplifier issue, since its operation is strictly dependent on *video content*. It will make things go dark and bright depending on how it adjusts the signal. There is an RF-AGC amp too, and that is OK since your antenna signals aren't affected, they're adequately taken care of before they hit the video-AGC.

Tough to do things like this without seeing for myself. The first thing to do is to isolate the problem to the component. That usually means using known good components/swapping, in your case I'd say hooking up your DVDP to another TV that works fine. I'm pretty sure the problem is your TV from what you've tried and said, but you will have to convince yourself before you consider other action.

Suppose you try another TV and become sure that's the culprit. I don't know if you do DIY, but even if you don't and just want to try a stab at diagnosing the problem to see if it's worth fixing (probably is if it's just video-AGC): go and get the sci.electronic.repair TV FAQ. Sorry, I don't know where it is these days, but a search should easily find it. This, and all their other FAQ's, are excellent and will allow you to narrow the problem down very accurately - like for a car, it's REALLY good to know what's wrong before you take it in for sevicing. Consumer TV's are notorious for their very poor soldering, a major cause of many problems. When the service guy replaces a part, guess what? Now the TV works, often because of new solder joints on the new part, there was nothing wrong with the old part. For instance, flakey solder joints can become temperature sensitive, as they get hot they stop working, so then they cool down, and then they start working again, giving a cyclic effect of the problem coming and going. This can happen to any part actually, but TV solder joints are famous for doing it.

All this speculation doesn't help much, so take your DVDP to a friend's house or a store (say you're looking for a new TV, you might well be) and find out for sure.