17C9 tube in a Philco??

[Hemingray]

Has Philco ever used a 17C9 in their radios? I have one (will take pics later) that came with one. However, the tube layout on the bottom has no 17C9 mentioned, However, it mentions a 12DT8 which I do not seem to have in this set. It is a tabletop AM/FM clock radio. The clock works, and only AM works. FM is dead silent, perhaps this 17C9 is the wrong tube for this radio? It's sitting where the tube chart has the 12DT8.

Also, anyone have an extra radio cord? this one was damaged at the back and let go in a spectacular way on me.

Forgot to mention: The 17C9 is made by GE.

[electroking]

Servicemen hastily installing random tubes in a radio or TV after the customer
has told them not to bother with a costly repair are not unheard of.

It is very unlikely that the chart is wrong! Good luck.

[radiotvnut]

I've seen this quite often. Usually done by ignorant servicemen or set owners who think "it looks like it would fit in the hole; so, let's see if it will work". At any rate, I'd try a 12DT8 and see what happens.

[Hemingray]

Guess I'll have to raid ebay for that one, don't have a 12DT8 at hand. Aside from pin 9 the pinout is exact to a 12AT/U/X7

And, as promised, here's pics. There's a number of N-732-124 on a sticker on the back below the AM coil.

the knob on the sleep control is also missing, if anyone has a spare.

[radiotvnut]

I've got the non-clock version of that radio on my "to fix" list. I'll open it and see what tube it has. Forget epay. You should be able to get a tube from www.tubesandmore.com or www.radiodaze.net.

[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.

[Old1625]

Originally Posted by radiotvnut

I've seen this quite often. Usually done by ignorant servicemen or set owners who think "it looks like it would fit in the hole; so, let's see if it will work". At any rate, I'd try a 12DT8 and see what happens.

Can you say "Burnt Resistor".......?

[Hemingray]

The FM is dead silent on my radio. AM works like a dream.

The socket does appear to have a contact for that 10th pin on the 17C9, which looks like it goes off to the socket shield.

I'll wait on radiotvnut to confirm the correct tube for me.

[radiotvnut]

I checked my radio and it has a Philco (looks original) 17C9 installed and the tube chart calls for a 17C9. My radio looks like yours minus the clock. And, I fired my radio up and it plays on FM. Note that the 17C9 is a ten pin tube. One pin is in the center while the other 9 are in a circle.

[Hemingray]

Originally Posted by radiotvnut

I checked my radio and it has a Philco (looks original) 17C9 installed and the tube chart calls for a 17C9. My radio looks like yours minus the clock. And, I fired my radio up and it plays on FM. Note that the 17C9 is a ten pin tube. One pin is in the center while the other 9 are in a circle.

Same chassis number? Maybe my tube chart is wrong then.

[Tom Bavis]

The FM front ends were often a purchased module... so they might have bought different a one for later production. For the cord, look for "cheater cords". I think I have a NOS 17C9 should you need one...

[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)

[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.

[electroking]

Originally Posted by electroking

Servicemen hastily installing random tubes in a radio or TV after the customer
has told them not to bother with a costly repair are not unheard of.

It is very unlikely that the chart is wrong! Good luck.

I stand corrected. Regards.

[solidjackson]

I once found a late model Philco console on the side of the road that used this tube. It was a weird model number like 30-30-1000 or something, and the radio itself was a simple looking circuit on a PCB. I think there was a 6DJ6 and two 12AX7 tubes, among others.