17C9 tube in a Philco??

[radiotvnut]

Originally Posted by Hemingray

My 17C9 checks out good. I have yet to get at the caps in here, I seen a coupla black beauties, and alot of disc caps. (the discs I believe are reliable)

In this circuit, the best test for that 17C9 is a new 17C9. I've seen tubes in FM circuits check perfectly good on a tube tester; yet, would not work in a circuit. The black beauties need to be replaced. Leave the disc caps alone unless one is found to be defective. Also, any parts that you change in the FM circuit should be physically placed in the same position as the original part and observe lead dress on any wiring. FM circuits can get real testy about this!

If a new tube does not do it, obtain a schematic for the radio and check voltages. It would also be nice if you have access to an RF signal generator. The signal generator will enable you to inject a signal into the different stages so you can see which stage is defective.