I recently purchased an American Flyer diesel horn control button. The controller works and generates the “diesel horn” sound from the #346 diesel unit. My problem is that the control button is not allowing power to reach the track. The train will only move while the button is activated to sound the horn. The wiring hook-up is done correctly. Has anyone experienced this problem?
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I am not sure what engine you have, a 346 is an 0-8-0 steam switcher. In any event all the air chime whistle controllers are wired the same.
Below is the Gilbert wiring diagram for use with AC track power from a Gilbert transformer. Note that the Base Post is directly wired to the track as well as to the control button. If the train only runs when the button is pushed that suggests that the green and red wires are not connected internally in the button when the button is not pushed.
It could be oxidation on the internal button contacts. To test the button disconnect all the wires. Connect an ohm meter to the red and green wires, it should read zero ohms when the button is not pushed.
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Welcome to the forum, AFSkipper!
That seems the most likely cause. Maybe there could be a broken wire/contact that only works when pushed back together by the button? Since AFSkipper says the horn does work, there wouldn’t be anything wrong with the generator tube.
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The only internal wiring diagram I have is for the 710 control box. On the 710, when the whistle is activated the connection between the red and green wires is broken and track power is supplied from the 15V post using the yellow wire through the tuning coil and the vibrator tube. I have never pulled a standard vibrator tube control button apart to verify it works similar to the 710 but with just one sound.
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Welcome AFSkipper , sorry I can’t help I only have one whistle control and it works fine. but mine will only work when the engine is in neutral .
Chuck
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Welcome aboard! 
I apologize, the locomotive is a 360/364 Alco Santa Fe unit. I checked the ohm reading on the red and green wires as you suggested and did not get a zero reading. All the wiring is hooked up correctly and I don’t see any obvious damage to the control unit itself. I’m thinking that there may be an internal problem in the generator tube and that I should open it up and check for a broken wire or damaged/corroded contact.
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You can open up the tube and as a minimum clean the vibrator contacts. There may be some issues with the tube. The tube is not in the track circuit if the control button is not pushed so it will not prevent the engine from running without the horn blowing.
The tube can be removed from the button and the train will still run. If the train does not run then the original problem is in the button. The fact there is not zero resistance between the red and green wires shows there is at least corrosion on the button contacts.
One final thing. There are four versions of the vibrator tube. Only #1 and #2 will work with the original button with the 364. I assume you have one of those two since the horn does sound when the button is pushed.
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I have Tom Barker’s Repair and Operating Guide, and he recommends cutting the generator tube near the plug end and sliding it off.
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Lets try to keep that a secret!
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Thank you for responding to my posts. I wonder though if the train would run without the tube inserted into the controller. The wiring hook-up diagram shows variable voltage from the transformer (red wire) entering the controller. Wouldn’t there have to be a physical connection for the variable voltage to get to the green wire that connects to the track for the train to run? There is no complete circuit if the tube is not inserted. The red push button on the control unit completes only the circuit from the transformer 15 volt terminal (yellow wire) to the yellow wire terminal of the tube to sound the horn. It does not connect to either the red or the green wire.
That is why I was thinking that there may be an issue inside the tube with the green and red wires.
I don’t know, just kind of grasping at straws……
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I do not have that controller on my layout. So far I have been working from published instructions and wiring diagrams. Tomorrow I will look for one of my control buttons and do a complete diagnostic on it.
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I found one of my steam whistle control buttons. It uses the “red” cardboard tube and is in new, unused condition. Indeed, there is no connectivity between the red and green wires when the button is not pushed. The internal wiring diagram I found is apparently incorrect. This does mean there is likely a problem inside the vibrator tube causing the track to be unpowered.
As you can likely tell, I do not use these controllers on my layouts. First, I do not care for the sound. Second, wiring all the power feeds to the track through the control button can become problematic on a large layout. Third, several decades ago I switched to modern transformers for track power. These output a chopped waveform rather than a pure sine wave. The harmonics in the chopped waveform cause the horns/whistles to sound constantly, not good. To eliminate the constant noise I unsoldered one speaker wire in all the Gilbert sound equipped engines I operate on a layout.
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Thanks for checking your unit. I know the diesel horn sound is kind of lame, but at this point I just want to know why it’s not working as it should. I am going to check inside the tube and will post when/if I can find an answer to this problem.
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