[codefox1]

Fora series set, the filaments should add up to 115 or 120 volts for today's service in theU.S.. So long as the pinout and tyoe is the same,a little juggling is usually OK; a string that totaled 130 volts would most likely be fine, but a string much below 115 volts is not recommended. Most tube types are still widely availavle, so usually switching sockets (loctal to octal for example) is not needed. I do save good loctal sockets from junkers "just in case."

If the tube sub doesn't clear up the problem it well may be a carbon resistor that goes way up in value as the set warms up. Many now routinely replace carbon resistors whilst replacing paper capacitors; easy and inexpensive;l less troubleshooting later on.