17C9 tube in a Philco??

[Old1625]

If the radio actually played the FM band then apparently the correct tube is in there, and the tube chart is wrong; the pinouts are nowhere near similar. If the radio is currently not playable a quick check of the tube socket in question should tell you; the center hole in the socket will have a contact sleeve like the nine around it if the 17C9 belongs there.

A 9A-based 12AT7 might conceivably work if you can get access to the bottom of the socket and unground pin 9, which is the center tap on the filament on the AT7, while the 12DT8 with 9AJ basing uses pin 9 for a partition shield. But the 12DT8 can probably be obtained with some patient fishing.