Testing Triple Differential Driver AD 8147
Differential current drivers tend to require a load. This is not the case for the output drivers in AD8147, as far as I can see. Adding a load of 100 Ohms should not hurt, though and is something you can try.
I would suggest a look into the AD8147 datasheet, especially Figure 31. There is an exact example how VSYNC and HSYNC are encoded onto the RGB signals. R, G and B are just your typical analog signals, so in case it is actually a random signal, you would see a random signal there.
Several points:


You should connect the probe grounds together and to system ground. If you don't do that, you risk your scope if there is a grounding error.
You also need to configure your scope to display the difference between the two channels, i.e. go to math mode and select something like CH1-CH2.

What is ve? Vs- and Ground should not be connected.


Also, make sure that J3 is in the right (as in the direction) position.