Something is drawing excess curretn through R24. You said you replaced the
caps in the sub-chassis, but that circuit appears to be the offending
circuit. I cannot quite read component numbers, but if noise appeared on
the screen bypass cap, it would be more likely to make the crackling noise
than a bypass cap further up the power supply chain. And, as Barry
mentioned, the coupling caps for that if transformer could be bad,
particularly C30.

Varying the selectivity control will change the load on C28 and C29, so you
might see if there is any change. It could also be one of those caps or the
rotary switch, although having the crashes go away when pulling V5 along
with overheating R24, points to the plate or screen of V5.

Check C27, the plate bypass cap, closely. That is a tuning cap and would
have some affect. Noise can be caused by a cold solder joint, but that
would not result in more current being drawn.

You are getting closer.

73, Colin K7FM