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I have the subject smoke unit that has a 8 ohm resistor and fan.  I don't know the original application but it looks to be for a diesel and connects to a mother board I assume.

With the 8 Ohm it looks like it needs 5 V or so to smoke.  It has 3 pins input (see pics).

I'm trying to use it for constant smoke, ( no puffing) on a Lionel Accessory 175 Rocket launcher.  I can provide it 5V from my accessory transformer Lionel LW.

All pins are open circuit except for one pair which gives me about 8 ohms.  (resistor?)

I applied 5V and got no action, fan running is what I call action.

Any ideas to get this running without more electronics??

Thanks BobIMG_6337IMG_6338


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Try jumpering the two outside pins together, that's usually the missing link on some of these smoke units.  If that doesn't do it, you probably have a fan power supply issue.  Top suspect is the LM78L05 regulator, next is the capacitor.  The diode rarely fails, but it might, it's a common 1N4003 diode.

Of course, you might have a bad fan motor as well, unplug it and try it with a DC power supply, no more than 5VDC maximum.

Last edited by gunrunnerjohn

You jump the outside pins and then just apply normal power to one outside pin and the center pin.  There is a fly in the ointment for your use however.  If you plan on keeping the 8 ohm resistor, you won't have enough voltage on the fan power supply at 5V in to properly run the fan.

I'd change the resistor to a higher value for your building use.  If you replace it with a standard Lionel 27 ohm resistor, you can run it on 12-14 volt accessory AC power after jumpering those two pins.


Now I know why I don’t hear the fan. Not moving at 5v but at 12 you would cook the resistor or at least the unit.
Not sure I have a 27 ohm but I have a 20 ohm that I use to upgrade Lionel steamers.
The 20 ohm should work since the rocket will have no more that a minute run time.
Thanks John.
Would it be safe to run that 8 ohm for 5 seconds at 12 volts to make sure my wiring is correct and that the fan works?

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