With the actual pins on the CRT, if you then get green and no red, then the CRT is OK, and the drive missing. Next swap the drive wires going from the main board to the CRT board, if it swaps, then the main board is duff, if it doesn't then the fault is on the CRT board.
A common problem on various sets is the feedback resistor around the video output going high or O/C - these are usually 100K or 180K, something like that.
Mind you, first thing to do is measure the voltages on the three cathodes!.