Ive got a wharfedale w42h40pe and suddenly this morning it will not show a picture on the av channels, just black screen or wavy lines, sound is still coming through though

That sounds like the backlight is switching off. It might be faulty. If this is the case the screen still shows a picture but it's not lit, all black.

It sounds that the main power supply section to your TV has the fault. The horizontal thik lines that appears crawling down across the screen should be of video 'HUM'. Have you replaced the main filter capacitor at the power supply section? If not, replace it along with the main rectifier. The AC power is rectifed by a bridge and applied ot this main filter capcitor. It will have a capacitance value between 120 to 350MFD 450VDC. Check this section. Measure the rectifed DC voltage acorss this main filter capacitor. It should be around 350VDC, if your home power supply line is 220VAC. If it is 110AC, this DC voltage will be around 165VDC; and it should be. If rectified DC voltage found lower than the input AC voltage, replace the rectifier bridge. In some sets, this bridge section have four diodes. Some other circuits, a bridge rectifier stalk may be used.

A few questions:
Are you using this TV directly on a cable line of do you have a cable box or satellite receiver connected?
Do you have sound and no picture on the AV inputs as well, or only on TV channels?
Is there anything on the screen or is it completely black? Has the picture collapsed to a single line across the screen? Is there a picture but it's distorted?
Does the on-screen menu and channel number display properly?

With a little more information I might be able to help you with this.

My television worked this morning and now only shows a blue screen. The sound works but no picture except for a wavy blue screen.

Wharfedale LCD3210HDAF this tv was working fine the night before .. when i turned it on in the morning the screen came on then instantly went blank .. although the sound is fine i am unable to get any on screen including menu an volume information and of course can any one help ??

Check out this site. These TV's are known for the CRT's going bad. This site shows how to make adjustments that could help extend the life of your set. Take a look at the first picture, if the lines look like the ones in the picture this site "should" help. The picture shows a problem with the red but don't worry about the color, look at the lines. I hope this helps.

this happens when your xbox overheats. its happened to me a few times too.

rate

'I to am getting only wavy blue lines, no sound, doesn't even show channel indicators. TV was off for 4 days, came home turned it on and ten minutes later this screen appeared, it wont even show the menu screen, different channels or video inputs no sound either.

I have a JVC AV48WPT4 48 Inches. Have perfect picture but fine retrace lines on the screen.

Can you tell me what could cause it?

Thank you.

Sounds like a convergence promblem.

Here are some of the most common symptoms of a convergence problem.

Screen looks 3D
One or more colors can't be adjusted when using the convergence menu.
Screen is bowed in or warped.

Here is a quick test....

Using your original remote go-to the tv settings then goto the convergence or magic focus section.

Try to adjust the convergence.

You should be able to move them up, down, left, and right.

If you can't move them in all directions your convergence chips are bad and should be replaced. This is a common problem.

Its a fairly easy fix on the Hitachi sets.

You can get a repair kit that includes all the parts from www.TvRepairKits.com. The kit includes a photo instruction guide, original Sanyo STK chips, convergence resistors, etc.
Everything you need to fix it yourself.