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The cherry switch opens and close by a hitting a  cam lobe, from the rear wheel set. My question is does this cherry switch open and close a circuit for a ground wire or a positive wire. I do not like the fact my fan driven smoke unit either is on or off. I would like to jump  wire,s from the cherry switch, to one of the fan wires on the smoke unit. To create an open and closed circuit to the fan driven motor, so it would turn on and off with the synchronized chufing of the locomotive.  Is this possible to Frankenstein this, without damaging any of the electronics. I would think it would be possible if it was on a ground wire. Thanks for your time.


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  • C&O smoking
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A lot of the Odyssey engines have chuff with continous smoke. The switch currently only goes to chuff in on the radio board where is connects chassis ground to chuff in, pin 17. To turn the fan on and off synchronous with sound you have a few choices. GRJ super chuffer will accept the switch in and output to both the fan and radio board. Some of us use the switch  to drive a double pole reed relay. One pole to the radio board and the other to the fan motor. Lastly use two micro switches on the cam with one still going to the radio board and the other to the fan. There is not always room for two switches and in some cases the cam is not wide enough, normally these cams only have two lobes so you only get two chuffs per rev. The cam gets replaced with a 4 lobe cam for 4 chuffs.

John has a turn key solution. The others require mechanical modifications that may include removing a driver to install a cam and requartering.

What you can't do is wire the single micro switch to both the radio board and the fan motor. One or the other, not both.


Last edited by Norton

Thank you very much for your time, and information. It seems to be a little more complicated than I was hoping for. I do not want to damage the electronics. I thought that maybe I could just cut one wire on the smoke unit motor itself. Run one side down to the cherry switch. Then from the other side of the cherry switch  back to the other side of the cut fan motor wire.  And just use the existing cherry switch to intermittently turn the power to the Fan driven smoke unit on and off, with the revolution of the cam. Providing it was a grounded circuit and not positive.  It was just a thought. Tearing down and servicing all these newer TMCC locomotives is new to me.

You can use the switch on the fan but you will lose chuff sounds. If you are OK with two chuffs which I assume this has you can use John's Super Chuffer to split the signal. If you don't have 4 chuffs and want at least 4 chuffs you can add John's chuff generator mounted on the motor and not have to deal with the micro switch at all. You could set it for 8 articulated chuffs or get a new ERR Railsounds board for articulateds that would not have 8 equally spaced chuffs. I know it can get expensive. Thats why a few of us use the low dollar but more time consuming approach.


I apologize for my ignorance, but I have looked at the installation instructions. And I am not even sure how to start to proceed, with installing the Super Chuffer II.  Does it replace the R2LC radio receiver board, or any of the other boards ?  Can I just use it for the smoke unit, or do you have to hook lights and everything else to it. Thank you

It doesn't replace any existing boards, it is just wired in.  You can ignore the lighting features and just use the smoke features.  If you look at the basic Installation Schematic in the instructions, you will just need to wire six wires to the Super-Chuffer.

  • Pin-1: Track power (roller)
  • Pin-2: Track power (wheels)
  • Pin-5: Chuff In (parallel with existing chuff switch)
  • Pin-6: Smoke Motor negative terminal
  • Pin-9: Smoke heater Hot lead
  • Pin-10: Smoke Motor positive terminal

So I can jump a wire from the collector roller to pin #1, for positive. And I can install a ground wire. Do I just solder wires onto the existing wires on the chuff switch, and run them to the Super Chuffer. And leave the original ones that are on the chuff switched, still hooked up ?  And do I just tap into the smoke unit, and smoke heater wires. Or do I  have to disconnect them completely from the smoke unit motor and heater element. And run new wires from the Super Chuffer to them. I guess what I am really asking, is do I just tap into the existing wires. Or do I actually need to remove any of the original wires to hook this Super Chuffer up. Thank you very much for your advise and patience.  I have the ability to tear these locomotives down, and change the worm gears, and completely service them. But electronics has always been an interest to me, but never my field.

The only thing you "disconnect" is the wiring to the smoke fan motor, those only go to the Super-Chuffer on the pins I indicated.

For the other four wires specified above, power and ground are obvious, that leaves two wires.

The chuff is just tapped into the existing wire from the chuff switch to the locomotive motherboard, you do not remove any wires and the original connection remains intact.

Finally, the smoke heater sense wire going to pin-9 is just connected to the hot side of the smoke unit wiring, nothing is removed.

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