Picture tube problem

Check vertical output circuits. They control the up and down deflection and when not working you get straight line across front of tube.

I found the user manual online, and the pictures in it are really helpful and make this make a lot more sense, but:
1. Press [SCREEN MODE], to switch the TV aspect ratio.
2. Press [SCREEN MODE] repeatedly until the normal screen displays.
NOTE: • Some programs may not offer all display mode options.
4:3 Programming
[Sidebar] Sidebar displays a 4:3 picture at its standard 4:3 size. Sidebars will be displayed on the right and left edges of the screen.
[Full] Full displays a 4:3 picture at a 16:9 size, with horizontal elongation necessary to fill the screen.
[Cinema] Cinema displays a 4:3 picture at a 16:9 size, with less horizontal elongation necessary to fill the screen because a little bit of the top and bottom edge of the screen will be cut off.
[Wide] Wide displays the center of the picture as original size and the outer sides of the picture will be elongated. The size of the picture will depend on the original signal.
16:9 Programming
[Full] A picture is displayed at 16:9 size as it is.
[Zoom] Zoom displays a 16:9 picture without changing its horizontal and vertical ratio, at its maximum size.
[Cinema] Cinema displays a 16:9 picture with vertical elongation.
[Expand] Expand displays a 16:9 picture with horizontal elongation

Source: LC320EM8 User Manual
http://www.manualslib.com/manual/47021/Emerson-Lc320em8.html?page=21#manual

Yes, this is rare but I have seen it before--not fixable if it is what I think it is----It is what is called a Dome effect---the shadow mask in the picture tube is actually contracting and or expanding depending on temperature---

Directly behind the phosphor coating (the stripes that you see on the screen) is a metal screen--the holes or perforations in it line up with the stripes on the phosphor screen.

Some masks either have a material or a defect causing the dome effect----Not likely to be anything else---a Pin amp problem will not usually act the way you describe but a shadow mask inside the picture tube will act exactly that way.

Generally this is not good news. Even in the event this TV is repaired, it will work very long. This TV has a horizontal problem. This is the most stressed area of any conventional TV. The Horizontal Output Transistor will need replace, the flyback transformer is bad, you have bad power supply with horizontal capacitors that are bad, and last, is a possible bad picture tube. This TV is not worth the effort or money to repair. Thanks for asking and show all hands of support!

The vertical sync circuit has gone bad...you'll have to have it repaired if you want to keep it

The vertical output IC LA7847 is failing. It will likely fail permanately and you will have just the horizontal line. The set will require service. Just do not run the set very long in this state. That thin white line can likely burn into the crt phospher and will show all the time thus ruining the glass picture tube...

The problem you are describing is called loss of verticle deflection. You will find this will require diagnosis and there is no simple answer to this repair. Most likely there will be either bad electrolytic caps or bad vert. output IC in the vert. circuit.

Sounds like the green tube is shot, tap on the green board see if theres a loose connection, with something hard plastic

Check for leaky capacitors in the vertical section of the TV or cold solder joints.
I would also check in the power supply.
Good Luck.

All symptoms indicate a problem in the vertical circuit,the first thing to look for will be loose conection on the vertical output IC,sometimes this IC goes bad completly and it needs to be replaced.If you are familiar with soldering electronics you can take care of it but if you are not too familiar you can play it safe and take it to a servicer ,it will be a lot less expensive than if they come to your house.Let Us know how it goes or if you need more information.