Hi this isnt a cat issue
but a TH2g digital issue output 2 H Sync & V Sync voltages (2.4v) are less than output 1 & 3 H & V (3.6v) so when feeding some Vga da's you may not get an image from output 2 this had me with some new da's boosting the sync from out 2 with some extra electronics cured the problem so this is one to look out for.But the strange thing is the R,G,B feeds are all identical so its a strange anomaly
all the best
Chris