Richard
Doug, I have a Philco 116-122. Mine's the large console model with one large speaker and 3 additional "clarifier" speaker cones. Mine has no 6H6 tube in it.
Either:
[1] Someone has inserted the wrong tube in the radio. On mine, there is only one socket that accepts an 8 prong octal tube like the 6H6 and that's the 5Z3 recitifier. The 6H6 most definitely won't work there! Don't plug it in with that tube in!!
[2] There was an "undocumented change" in the circuitry of your set. Several of these changes have been noted for the 116-122 radio, but none has been noted so far involve using a different tube.
The only spot a 6H6 could be put to use would be in place of the #37 2nd detector. But this tube has a 5-pin base. The set would require an 8-pin octal socket to accomodate the 6H6 (or an adapter), and a wiring change.
Is there a tube-layout sticker inside the cabinet anywhere? Does it show the 6H6? If there is no sticker, where is the 6H6 installed?
You might post your question over on the "Philco Forum." Ron Ramerez and Chuck Schwark hang out there and are Philco "experts."
www.philcoradio.com