Not only did I acquire a black screen A1200 (Which is now fixed) , but I had an A600 with missing colours (G then R) outputted via RGB, so this is how I fixed it, it might help others when googling.
When the caps leaked it rotted the traces underneath the resistors , no break was actually visible because it was where the trace meets the pad. I had replaced the caps and cleaned the board already, but when I tested the colours were missing.
So when you have no red or no green on RGB you may need to reflow and fix the breaks underneath the resistors.
On the left within the circle is a 33K and 1K ohm resistor and a voltage detector, these are for the green signal and the ones of the right are red. you basically need to ensure using a multimeter that the signal from the 1k resistor goes to pin 2 of the voltage detector and also to the 33k resistor. if it does the problem is else where however if you have no continuity desolder the resistors, use a fibre glass pen to get to the copper and go over it with solder to hopefully fill in the hairline cracks. Then you can clean and reuse the resistors just make sure you clean then up first.
Hope that sort of helps some one!