[Yamamaya42]

Here is how I see this set working ( my take on it ), you have the thermistor R211, cold at 26.5 ohms, as it heats up. It gets lower, they put this in as a protect timer to keep the bias low as the tubes warmed up as not to shock the caps with overvoltage until the heaters were warm enough to load the circuit down enough.
Without tubes in the set, this feature is defeated, and the bias out of X2 at C1 can easily reach over 400v or more and may have damaged the new electrolytic capacitors you have put on there, of course there is no way to know for sure if this is what has happened, but it is possible.