Hi Sam,
Tried cleaning the LVDS connector between Logic and Main boards? You could also try test patterns. This would rule out main board.
Unplug TV and remove connector between PSU and Main (at the Main end).
From the legend on the PSU end locate PSU-ON and any RETURN pin and short these two out at the free plug end. A pigtail offcut is ideal.
On the Control, locate the 4 or 6 pin test jig and short out the 2 highest numbered pins - an alligator clip is ideal. Could be pins 6/5 or 4/3.
Plug in the power and observe the test patterns for clarity.
If they are fine, Main board is faulty (as it's been taken out of the equasion).
If they are not, you're not much the wiser. Could be the panel, but not likely.
Ever trying, Bruce