I haven't an answer for you - just wanted to make the observation; having voltage on a test point is no guarantee current is flowing through the circuit and for current to flow, at the other end of the circuit there must be a return, ground path or whatever.
There is a trend these days for power to be supplied to one end of a circuit and the switching or control elements to be at the other end. Commercial circuits are devious and it takes a fair amount of skill to test them and obtain meaningful results.
One problem a person has with testing a tv that is as much computer as tv, is many circuits have a level of intelligence for self protection - they sort of know if they aren't working right and can shut down. Modern thinking seems to be any lengths to prevent fire...