USA Trains Smoke Unit Inquiry

Madman

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25 Oct 2009
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OK, I have a USA Trains Fan Driven smoke unit. Along with the smoke unit I have a USA Trains circuit board that that reduces the power to the smoke unit. These normally would be found in an SD-40. However I am using them in an LGB loco.

The smoke unit has two male plugs. The circuit board has three female sockets. I know, who would complain about too many females. All seriousness aside however, I would presume that the socket off to one side of the circuit board is the power socket. While the other two are for the smoke unit and the fan. The odd thing is that checking the two latter mentioned sockets with a volt meter, one puts out 6 volts while the other about 2 - 3 volts.
 

enginear joe

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18 Mar 2013
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I am not an electrician. I don't have my SD40-2 apart now.
I have a SD70MAC smoke board here. The input is on the top right lets say. So the resistor out is the bottom right and the motor goes right above it. All are labeled right on the board.
I believe the motor needs less voltage than the resitor.
 

Madman

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It's been a long time since I played around with any USA Trains fan driven smoke units. I can't remember how I wired the last one I did. I don't have that locomotive now so an example is not here to guide me. I am thinking of purchasing one of the fan driven smoke units and installing it in an LGB Caterpillar diesel that I am kit bashing.

The smoke unit works off of a PCB. I suspect the voltage to the PCB could be variable based on track voltage or in my case battery power.

Anyone care to comment an enlighten me ?
 

PhilP

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Have a shufty (look) at George Schrayer's pages on these. - Though yours might be a later design?

Girr.org

PhilP
 
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George's site is getting pretty antique unfortunately.

He only shows the early "boiler" type smoke units, nothing in common with the fan driven units.

The separate board provides separate power outputs for the fan and the heating elements.

What input voltage did you give that board?

Normal outputs are about 5 volts for fan, and a bit more for the heater...

I normally remove these boards, so have not tested them extensively, but I know what it takes to drive the fan and heater:

read this page, picture of board, connections to the unit, and voltages: