Tv with built in player plays perfect then shuts off

What does "playing up" mean

This shows up in older DVD player that do not play recorded DVDs.

The video heads are clogge,need to clean or replace by a profeessional...

Here is a manual for your unit http://www.docs.sony.com/release/KDL40HX800_qs.pdf

As far as watching a DVD, I wasn't sure if your TV has a built in player or not. If you have a built in player simply insert the DVD and change the input channel to DVD. If you do not have a built in player, check to see how your DVD player is attached to the TV. Insert a DVD, then cycle through your inputs with your Input or Video Source button until you see the DVD playing.

Hope that helps!

i also have this tv.same problem too.i bought two multimedia bose speakers for 100$. they are actually designed for a laptop but trust me....they are better than most so called surround sound speakers designed for tv's.these tv's are not known for their built in speakers.

If the tv remote has a input control button(video/antenna), you should be able to play your dvd thru this .

goto your menue setings and slect sround sound and set up to external sound system.

Had problem checked by local outfit called "Circuit Pro"; their analysis was compatibility.
Actual answer was that the Toshiba required a better quality input from "any" VHS source.
I finally took a "less than perfect" VHS tape with me when I returned the Toshiba TV to the store and demonstrated the problem to one of the TV sales people. He played the VHS tape through a display VHS/DVD player to three different brands of TV. The picture was often "black screen" on a Toshiba, but was merely poor quality on the other two brands. I upgraded to a Sony KDL26M4000 from the Toshiba 26AV502U.

Try putting in a VCR tape let it load and hit stop. If the set stays on it's the VCR deck causing the problem. It will be either be bad sensors or LED or possibly the mode switch. Let me know if this helps.