JVC 36" color sterio tv lines on top of screen

Screen

Check and replace all the electrolytic capacitors at the vertical output section circuit. Replace the supply smoothing electrolytic capacitor to video output supply voltage.

tv turns its self off i unplug it plug it back in it will flash on not showing picture it u can her it flash on and right back of some times it will not flash in back of tv and i can hit power it will flash and go off every now and then it will come on show picture after being unplugged and plugged back but then shuts off

Start with a replacement Tcon board

Pls. check your antenna line if it is still connected. Blue screen happens only if your
tv is not getting any signal from your indoor or
outdoor antenna.

Have you tried another S-Video patch-cord?
Some cheaper ones short across pins.
What output from DVD are you using?
If composite video 'Yellow' RCA socket, a cheapo cable can also create sync problems ie signal timing, causing patterns on screen.
The S-Video is actually 2 signals - one for Chroma C and the other for Luminosity Y. With S-Video to S-Video connections, this gives better quality than composite, as each line can handle separate voltages, levels and frequency for Chroma = pixel color and luminosity = pixel intensity.
Composite has to cram all this info onto one channel, so signal quality is lower than S-video.
A hack that videophiles use is to place a 470nF ceramic capacitor across the 2 signal pins, instead of the cheaper just bridging them together.
This apparently helps to re-sync the combined signal from composite.
A tester on ohms and steady hands can test whether your cable is cheap-shorted type, or better synced type.
Across C and Y pins:
0 ohms=shorted
high reading or open=small sync cap
If making own cable mod:
Pins are closely spaced, so easier way is to strip and dress cable near S-Video plug, solder wires to cap accordingly, join composite to cap & Gnd as shown, insulate.

I'm assuming you used STK392-110 for a replacement. You could use STK392-150 for greater reliability and don't forget a good heat sink compound. (VERY IMPORTANT). What it sounds like is something even the best of techs battle. You probably didn't buy original Sanyo STK's but instead got a couple of the JApan knock-offs. Might I suggest you carefully replace them again and this time order them from B&D Electronics, Bdent.com on the net. You are assured of getting quality OEM replacements that way... We've had a bad batch that purchasing ordered quite some time ago and 2 out of the 14 ordered worked.. The rest were DOA (dead on arrival). Good Luck Bill