17C9 tube in a Philco??
 

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.

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'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.

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.

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.

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.

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

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.

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.

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...

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.

I stand corrected. Regards.

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.

Well, was able to find me a NOS 17C9 on the cheap. When it shows up I'll give er a try.

New tube in, however, FM is still silent. Does anyone have service data for this radio?

Me again. Did someone here have a handful of schematics for radios handy?

This would be later production than Bietmans and Riders...might be a Sams folder on it though. What was the model #? If it was in the thread maybe I missed it.

I assume you found a power cord, or do you still need one? If so post a pic or pin spacing measurements.

It's about the same as your standard cheater/radio cord.

The model # is likely on the back, the whole thing almost looked like it had been left in the weather. Tried subbing in a 17EW8 (equiv. of the 12DT8 that the tube label had listed), with no luck.

I'm guessing the filament is working and the tube lights up-do you have a VOM to check plate voltage?

You could have a burnt resistor, a bad coupling cap in the FM section, a bad antenna connection (probably uses the line cord as an antenna), or an open interstage transformer in the FM section. Or a bad solder joint or PCB trace.

Having fun yet? :D I love old radios with FM but they are a PIA to get working right. I got several deaf ones to prove it.:sigh:

When switched to FM, there is no sound whatsoever. Not even a crackle.

Have my DMM, next thing to do is check for plate voltage on the 17C9. Pin 10 of the 17C9 (which is a cathode) is tied right smack into ground. Should a cathode be tied directly to ground like that?

Did a meter test, getting about 102V to the tube, so plate voltage appears to be present. Seem to have a silent lower end of the AM band too.

Well, after slipping a 12BA6 into the circuit (some fool had crammed a 12BE6 in there.), the FM band magically sprang to life on me. Now I have a better clockradio to get me up in the mornings :D

The 17C9 apparently belongs where it is, as FM is working fine with it. So mine has an incorrect tube layout. Anyone happen to have one of the little front knobs for it? The one on the Sleep timer is missing.

Glad to hear it is working! To answer your one question, yes, some radio cathodes are tied to ground. As for those troubling dinky knobs, this guy makes 'em:

http://www.renovatedradios.com/clock_knobs.html

I you have any matching knobs on your set, you may try casting a new one in epoxy as well.

Is your am band still getting quiet on the lower end?

It is, yes. Not gonna worry too much about that at this time as for getting up for work in the mornings, I'll wake up to a good local 90s station.