Sony Monitor problem. Any suggestions (1 Viewer)

[John Morgan]

I have a 35 inch Sony Trinitron. About four years old.
My Sony DVD player's video is plugged directly into the televsion by way of SVHS plug.
My laser player has both picture and sound through my Denon receiver.
The reason I think the problem is with my television is because the DVD is plugged directly to the TV and the laser is running through the receiver to the TV and the same problem shows up on any of my direct video sources...not cable or video tape. So I am confident it is not with my cables, or anything other than the television
The problem (and I am not very versed in the proper explanations and correct words) is that there is a sort of dark wave-like flowing thing on my screen. It seems to be seen more on sky or brightly lighter scenes, and this darkness doesn't blot out the screen, but just is there. It seems to move like a slow dark wave. This thing even moves when the laser or DVD is in still mode.
I found a SONY web site that described all the adjustments that can be made to the set that are not on the regular menu, but I don't think I am qualified to play around with color temp and all that stuff.
Do you think I need a serviceman to come in and does this kind of thing need a rather sophisticated adjustment?
Thanks,
John

 

[Allan Jayne]

Looks like one of these "ground loop" problems. I don't know the systematic way of curing ground loops but one thing you might try is to unplug everything, absolutely everything, from the back of the TV. Then connect one thing at a time and see if/when the waviness comes back. Also try reversing cables end for end, I was told that cables are sometimes constructed with the shield bonded to just one of the end plugs for the purpose of reducing ground loop problems. Cables with defective grounding, for example the shield should be bonded to just one plug but that bond is broken, are not always easy to detect.
Perhaps you find that one source device when plugged into the TV is responsible for the interference even though some other source is selected for viewing.
Also things behind the wall against which the TV sits (lawn sprinkler controls, washing machines, etc.) can cause interference including while viewing DVD.
Other video hints: http://members.aol.com/ajaynejr/video.htm

 

[John Morgan]

Thanks Allan. I will give this a try.