Not really if not a tech. Some things are obvious checks, like running all the picture controls through the range. Checking all available inputs to make sure it is not isolated to the tuner or a/v or svideo inputs. If the set has PIP, checking the operation of the PIP and color in the little box. Then checking the color burst crystal to see if it has good solder connections and is oscillating.
It is only after doing all of the above do I start hunting for a schematic to track down what pin does what and to find the easiest to get at common test points with my scope probe. Luma, Chroma, Vcc, etc.
This is why I always list where I am at when I do have to ask another shop tech for help. Often times it is usually something that was missed, other times it is something they have seen in a not obvious circuit area.
Usually a couple of short sentences will do. Tv has no color, color and tint controls have no effect, the color burst crystal is verified running. I need some areas to test to go any further, I have no schematic or service manual on hand.