[old_tv_nut]

Ok, now you have a chance to find out what part of the loop is dead.

If you have a scope, connect to the top of C198 (4700). If you don't have a scope, connect a DC voltmeter there. Center the AFC balance control. Tune the oscillator so the color cycles through slowly, and you should see the voltage cycle slowly also, as the phase detector cycles through its full range. I don't know what the normal range is, but it should be at least a few volts variation, maybe +/- 10 from nominal zero at most? [Note that the schematic says the nominal control voltage on the grid of the reactance tube is zero volts, so the phase detector output should vary +/- around zero when it is out of lock.] If there is no variation, then either the burst keyer or the phase detector may be dead. If there is a variation, then your problem is still in the reactance tube or oscillator.