# USA Trains smoke unit with RCS throttle



## Jim Schulz (Aug 10, 2009)

Wondering if anyone has done this: I've got a USA Trains smoke unit with circuit board that I was told is the same used in the USA Trains Hudson and Big Boy. I'm hoping I can install it in my Bachmann 4-4-0 (it will fit) to have the puff of the smoke unit sync with the chuff of a Phoenix sound board. If no "puff with chuff," then straight smoke with fan is OK too. Power is 14.4v battery under RCS control.


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## Greg Elmassian (Jan 3, 2008)

The unit in the Hudson is the TAS unit. Yes, it can be used, but you need to understand the unit. 

The info you need is on my web site, search for: "tas smoke" (the search box is at the top of every page). 

Be sure to isolate the phoenix chuff input from the TAS one, i.e. put a small signal diode on EACH of these 2 leads before connecting to the chuff "Switch"... DO NOT HOOK POWER UP BACKWARDS!! 

Regards, Greg


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## Jim Schulz (Aug 10, 2009)

Unfortunately that was not the unit I was given. It looks like the unit I have is the standard fan-driven unit for diesels. So, let's make lemonade out of lemons. I'm thinking I can't get pulse (puff with the chuff) out of this one, but how about hooking it up for constant fan/smoke or increased fan/smoke with increase in power to locomotive motor?


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## Greg Elmassian (Jan 3, 2008)

There's 2 USAT smoke units here in this picture, the circuit board for the 2nd unit is on the motherboard on the chassis.

Does yours look like this?










They run from track voltage.

Regards, Greg


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## Jim Schulz (Aug 10, 2009)

Yes that's it. One smoke generator with built-in fan and separate circuit board. Can I get it to give constant smoke or increased smoke with increased motor power?


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## Jim Schulz (Aug 10, 2009)

I'm thinking I may be able to either wire the smoke unit power leads to either the battery switch for full 14.4 v power or the the motor "M M" terminals on the RCS throttle for variable power input?


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## Greg Elmassian (Jan 3, 2008)

Constant smoke, built in regulator, constant fan speed. Variable input will give you less smoke at lower speeds, but there's really not enough to go to the trouble. Most people want more output, so hooking to motor leads will probably give you a lot less smoke all the time. 

They are not huge smokers... 

Regards, Greg


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## Jim Schulz (Aug 10, 2009)

I think that will do the trick! Thanks! A good fireman does not produce much visible smoke anyway. And often the puff and chuff is not that discernable in real life at least at speed.


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