DVD picture is crystal clear, but wavy lines when using cable. Connected a different tv to same cable and picture is fine. internal coby tv to cable connection must be bad?

Move other devices as far as you can from the TV. A motor on the same circuit can cause wavy lines too. Try a different set in the same location to see what happens. If different results, probably a bad filter or capacitor in the TV.

Try it on different inputs like out from a box, direct cable or a DVD player etc to see if problem is isolated to one input on the set.

test test test 17:05
danke bitte
do not answer test test
sorry

The best suggestion I would advise is to buy a shielded scart connector & connect that from your DVD combi to either AV1 OR AV2. It sounds as if you are picking up RF interference from your current connections, this can sometimes happen if the cables do not have adequate shielding.

For the buzzing noise try tipping tv jently forward and jently placing back.

A problem like yours is NORMALLY NOT the TV set's fault....it's the Cable.

I'll bet you see thin lines moving across the entire picture...they are slanted like this >> \ \ \ \
That's generally caused by a bad ground on the antenna cable OR it can be the cable box's MODULATOR.

Try using your VIDEO OUTPUT off of your Cable box and see if the wavy lines are still present. If they are the Cable box needs swapped with a good unit.

You can also verify this problem by checking your TV with a DVD player...no lines indicate the TV is fine.

If you have problems with the DVD player's picture, then you must have dried out filtering capacitors on the Video board IN the TV set...

And THAT is not an easy fix if you do see lines with your DVD player.

Herringbone pattern?
House stray AC 60hz signal is getting into the cable b/c the shield is not properly grounded. Call the cableguy

Are the wavy lines horizontal or vertical? If they are horizontal and up near the top of the screen it could be 60HZ interference from a power cord running over the cable from the DVD player to the TV. There could also an internal breakdown of the shielding by the power supply of the DVD player. If the lines are vertical it is likely the cable or maybe the input jack on the TV. Could be a number of things.

it could be any of the things you listed, the coaxial output on the dvr, where it says channels 3-4 out, the cable , or the coaxial input port on your tv. the dvd player is probably hooked up with rca cables (red white and yellow) so the reason you dont have the issue with it is because its on a different port, one solution would be to hook your receiver up to the tv using this kind of cable, this would also get you stereo sound, you would then watch dish network programming on a video input channel,
if you want to narrow the problem down, i would suggest hooking a vcr up with the cable thats connected to 3-4 out, play a tape and see if the issue continues, if not the issue is with the dvr, if so try a different coax cable, if this resolves the issue, the issue was the cable, if not unfortunately the issue is your tv

This may indicate a problem with the RF tuner. When you are using the DVD player is the output of the DVD using the F (RF Coax) Conncetor or is the DVD connect to the TV using the Video/Audio cables (either Composite (Red, White, Yellow) or Component (Red, Green, Blue)). I am do however believe this to be a RF tuner problem. Make sure that the TV is set to channel 3 and the cable box is connected to the TV (set to channel 3). What you could also do is get digital cable and use the video output jack as the input to the TV on one of your aux positions.

I would first make sure the tunner is on channel 3 when using the regular cable box, or if you are using the TV's cable ready features make sure the tunner is working correctly, this might have to be done by a qualifide TV repair person.

I hope this helps
Thank you,
Shuttle83