New member, Philco has low volume

Philco PT-25 has low volume. Turing the volume control does vary the level. All the tubular caps have been replaced and resistor values are in range. The tubes have been swapped out with no change in volume. The set pulls in many stations, but the volume is low. Some times after it warms up the volume returns to normal. There are some mica caps that have not been changed.

Does this set have locktal tubes? If so, dirty sockets, and, coroded tube pins would be a major suspect.
After that, poor connections, and, a bad speaker......
Bill Cahill

It has locktal tubes. I found pushing the 35Z5 returned the sound to normal. Tried cleaning and adjusting the socket connections, made no difference. Will have to replace the socket. Thanks for the response.