I HAVE A HALF SCREEN. BOTTOM HALF LOOKS GOOD TOP HALF HAS WHITE LINES WITH A BIGGER WHITE LINE SEPARATING THE TWO. IS THE PICTURE TUBE GONE OR IS THERE AN ADJUSTMENT I CAN MAKE? TV IS A RCA F25645

If you wish to get some details; check the site linked here. Pull up older posts. Surf the site with patience. http://electronicshelponline.blogspot.com/
Line, faults & possible causes to both Plasma & LCD screen are given with illustrations. You can get an idea about the fault to an extent.

give a good whak on back of picture tube

IMO Seriously for $119 it's not worth it.
However, it does sound like a capacitor problem
If you are "Serious" about fixing I'd find a TV repair Forum.
Else I'd go here and get a new one.
https://www.walmart.com/browse/electronics/32-inch-tvs/3944_1060825_2489948_7156390
Best Wishes.

If you wish to get some details; visit the site linked here. Pull up older posts.
http://electronicshelponline.blogspot.com/
Line faults & possible causes to LCD & Plasma screen are given with illustrations. You can get an idea about the fault to an extent. Faults to all LCD & Plasma screen are similar, irrespective of its brand and screen size.
Search the site by type in the "BRAND NAME" of your device; (Exclude the model number), in the "Search box at the top right of the display window of the Homepage" to get gathered related posts

T con board is responsible for the image you see on screen as well as any anomalies.

Without seeing the lines I can't be sure what your set has wrong, but here are a some possibilities:

If the lines are lines are confined to the top inch or two of the screen and the picture looks otherwise normal, the trouble is bad capacitors in the vertical output circuit. Fixable by replacing the bad parts.

If diagonal lines are across the entire face of the picture tube and the picture looks washed out, the trouble is often a bad capacitor on the 200-volt line to the picture tube. This may be on the main circuit board near the horizontal output transformer, or on the small circuit board plugged onto the end of the picture tube. Again, replacing the bad capacitor can fix this.

If your TV is actually an RCA, someone may have bumped a rear-panel adjustment. On the back of the TV near the bottom right are two small knobs. RCA left these adjustments exposed inside of putting them inside the set like other manufacturers. These sometimes get bumped if someone was behind the set cleaning, or if a pet got back there and hit them with a tail. The top knob adjusts focus, and the bottom knob adjusts something called G2 or screen voltage. If this gets turned up too high it can cause the faded picture and diagonal white lines. Turn the adjustment down until a black screen looks black instead of gray.

A bad picture tube or horizontal output transformer can also cause lines through the picture. If this is the case with your set, it's time for a new TV. The transformer is relatively inexpensive but labor costs aren't, and the repair bill may exceed $200. If the tube is bad, there's no point even considering repair. The tube cost alone exceeds the cost of new TV.

Hopefully your lines are easy and cheap to fix. Good luck, and thanks for using Fixya!

sounds like a vertical problem, usually you'll see one white line across the screen, but one I worked on would come on and the bottom half of the picture was gone and there were lines across the top of the screen.

If you know how to solder & can find the vertical output chip then you could try resoldering the pins. If this doesn't fix it then it needs new parts.

Try the below link...

Sony has identified a limited number of VGN-CS series computers which may display a horizontal line on the LCD screen.

Click here for more information

it looks like some caps are bad in the set.
Have it serviced by a TV repair shop

This sounds like a convergence problem. This is a common problem that is usually fixed 98% of the time by re-placing the STK392-020 ic or STK392-110, and check the fuse devices on the covergence PCB. I'm sure the actual parts numbers depend on the peticular brand. Good Luck!