Philco radio cap problem

[radio nut]

The Philco 41-842 that I needed help getting a diagram for is giving me problems .There is one particular electrolytic cap in the 1LB4 (output tube)heater line that keeps getting very hot. I have replaced it with a new, still tests good cap. The diagram calls for a 100 mf cap 25 volts and the original sectional cap had a 200mf 25 volt in there.I used my digital meter and it does not show ac from the plus or ground of the cap to chassis ground or with my test leads on the plus and ground of it. I show about 4 volts dc from the pos to ground. One side of the tube heater does go to a grid inside the tube.I am lost,since I am not overvolting the electro. and I am not showing AC either ,but if I unsolder one end and test it with my cap checker it shows good.There is also an electro. in the other leg of the heater and it stays cold.The radio is fully recapped, the original speaker is gone. I do not know what the resistance of the output trans. should be so I do not know if it is an issue.I do have a speaker currently hooked up to the secondary of the output Trans. and I have no sound , hum, anything.Any Ideas?