Vertical lines - not TCON board - any ideas?

Hi,

I have a Samsung UE46ES7000 TV. For a while, I've had discoloured vertical lines on the right-hand side of the screen.

The lines appear on the built-in menus and test page, so not the inputs.

So far, I've tried the following, but had no luck:

1. Reset the TV to factory defaults.
2. Removed and reseated the ribbon cables going from the TCON board to the LCD driver boards (if that's the correct term?)
3. Swapped the ribbon cables around - problem stayed and didn't move to the other side of the screen.
4. Reseated the other cables going between the three main boards
5. Inspected the mainboard and driver boards for any visual signs of damage - none found.
6. Applied pressure to the various tabs connecting to the panel.
7. Tapped / applied pressure to various ICs on the mainboard.
8. Replaced the TCON board and the ribbon cables for both TCON > driver boards and mainboard > TCON.
9. Applied pressure around the edges of the panel.

Still no luck unfortunately.

Here's some pics:

Any ideas? Is it worth me buying a used mainboard to test, or is it looking more likely to be the panel / something else?

I've attached lots of photos.

Thanks in advance!