I was thinking, if the problem is in the flyback wouldn't the TV stay in standby with the red led on?
Because it doesn't even do that!
The direct answer to that question is, under some circumstances, yes.
For instance, if it were going into shutdown.
But as an old-time tech once observed:
"You can't shutdown something that never gets started"
If you checked the horizontal output transistor (espectally e-c) and it's not shorted, and you have have no collector voltage(sometimes you have to unsolder the collector and read the circuit voltage), you most likely have a power supply problem. Check things there.
The transformer in the power supply? Most likely, no.
Keep in mind what a switched mode power supply is doing:
You are simulating A.C. in the psu transformer by turning the transistor/output device on & off very fast, thus creating secondary voltages that start the set.
Consider, if you "float" the collector of the horizontal output transistor, and you read a dc voltage of 150v or more, check the emitter circuit of the horizontal output transistor. You may have a small resistor between the emitter and the circuit ground that's open.
No luck with any of this: invest in a schematic.