Vertical problem when I turn on the set I see a lot of white lines on top, it seems that the picture is folded, after a few minutes the picture is O.K.

If you've ruled out that the source you're displaying from is good, I would contact vizio for a warranty repair

Case 1:
If the horizontal lines are red, green or blue or white, and are slanted about 15 degrees up going left to right, they are "vertical retrace" lines. These are caused by the beam current in the offending gun being left on while the vertical deflection is retracing from the bottom to the top on its way to start drawing the next frame. The usual cause is the CRT screen setting being too high (too bright), but (rarely) it could be something wrong with the vertical blanking circuit. Since it is dependent on vertical position, I would check the power supplies feeding the vertical deflection circuit and the CRT bias voltages, especially if they share the same filter capacitor.

Case 2:
If the lines are true horizontal, and colored similarly to the picture (sometimes alternately white and colored the same as program material), the top of picture is folded over itself because of over-voltage distortion ("clipping") in the vertical drive. In this case, reducing the height of the picture also reduces the fraction of the picture with the lines, and may eliminate it. If you are unable to get a full-height picture without the lines, then you should check the vertical deflection circuit for leaky capacitors (also check the power supply voltage going to it).

Case 3:
Several times I've observed bright white lines with random interruptions at the top of a picture supplied by the local cable company. These often occur on one or a few channels for a time (once or twice I've seen it on all channels), and go away after a while. This is a glitch in the cable service.

Case 4
You have a zone of weird colors at the top of the screen. This is probably caused by magnetization of the shadow mask inside the front of the picture tube that is not being erased when the TV is first turned on. Check to see if somebody left a magnetized object on top of or above the TV (look behind the set also). If you find something remove it, turn off the TV, wait a few minutes, then turn it on again. (Explanation: the TV has an internal demagnetizing coil that operates only when you first turn it on. It uses a self-heating temperature-dependent part to gradually reduce the alternating current going through it to override and "fade out" any stray magnetism in the shadow mask.) If the internal demagnetizing (AKA degaussing) coil isn't strong enough, you'll need that "ghostbuster" gadget again. If you don't find an external magnetic source, the internal coil may have slipped out of place at the top of the picture tube and is too far away from the shadow mask, or something is wrong with the degaussing circuit.

If none of these cases match what you see, try a more detailed description of the lines and I'll give it another shot.

For how many years this TV with you? Most tv now a days after few years of using vertical IC solder started to dry(dry solder) you can try to re-solder or you may check also two capacitors (100uF/35V) for most JVC model has this symptom with this parts changes its electrical characteristics. If still problem persist replace vertical IC. Hope his helps, Good Luck

well its all new now could be bad caps or vertical i.c. okay if you have a esr meter check around the i.c. for a leakey cap good luck

check for dry electrolitic capacitors around the vertical output section

White horizontal line (no vertical deflection)
Check / replace R548, R549
Sound but no picture except for a couple of horizontal colour lines
Replaced the frame chip TDA8356, set now ok
Severe vertical jitter on picture, horizontal sides of picture ragged
Replacing the TDA4950 cured the fault
White line down centre of screen (top to bottom}
Replace C805

In electronics dust has nothing to do. cleaning will not solve your problem your problem is due to trouble in vertical section. mostly it is due to electrolytic capacitor in vertical section is defective.it is common problem. also check supply to vertical section. "THE SCREEN SHRINKS TOWARDS THE TOP OF THE SCREEN FOR A FEW SECONDS BEFORE THE PICTURE TURNS UPSIDEDOWN THEN TURNS BLACK." is called fold over. regards thanks

"Guest" obviously has no idea what he is talking about. There is no such thing as "frame section" and if the vertical IC, ramp generator or vertical hold circuits were bad, you would have no vertical at all. If you mean that there are thin white lines at the top 3 inches of the picture, and the top of the picture seems folded back on itself, it means that the pump-up capacitor is going bad in the vertical output circuit. This is a very easy thing to correct but should be done by a qualified tech.

If you have a picture but the top is folded over, your vertical IC is probably good and you need to replace the pump-up capacitor next to the IC. When the pump-up cap (typically a 47 or 100uF 35V cap) is open then the picture will have white lines and foldover at the top. The typical vertical output IC is the LA7838, but I am not familiar with exactly which output IC your set uses.

suspect it's 1 or a couple of bad capacitors in the vertical deflection circuit the caps are in the 400 series, c400,c401,c402, etc... check or replace c414,c418 & c417