[andyw25]

So, as suggested I've had a good look at the control board that had the corrosion. Swapped this with the spare from the parts chassis, again this appears to be from a foreign market set but even with this board swapped, no change, fault remains the same.

I'll attach some pictures, the pictures showing channel 82 are using the spare board and pictures showing channel 1 are using the original board.

I know the tuner/IF modules on these caused issues, but I've already changed the electrolytics in there and checked/reflowed joints etc according to the service bulletin. Also can't figure out where the horizontal adjustment is as you can see it's not quire correct.

I'll attach some pictures of the RGB board, can't see anything in the service manual referring to a Decoder so I'm assuming they are combined but I'm not sure, I'm not very familiar with decoders.