Atlas smoke unit

Yep, if they're using the one with the thermal sensor, maybe it's misplaced.  Pretty hard to know without seeing it.

The blue device can be too close to the heat resistor.   Over fill can flood the fan, another problem.  

I checked the component pictured and it is about 1/8 inch away from the resistor.

Move it slightly farther away, 1/8" is a bit too close.  Try maybe 3/16 to start and see how that works.

I move it to about 1/4", motor still runs in shout bursts.

Are the resistor and thermistor in good contact with the wick material?  That will prevent it from running solid if they're not.

yes they are and the wick is wet. Is there a way to test this by jumping anything?

Check the current to the locomotive and see if it spikes when the smoke runs.  When I had one of these cycling like that, it was shutting down the smoke element power but the fan kept running, this is normal operation.  The smoke element power will cycle as it runs, you could have a bad board in yours that is causing the fan to stop.  If it's an OEM unit, it may also be jumped for steam, in which case that might cause the motor to stop.

I just connected the TAS smoke unit up and measured the current as it runs.  The smoke stays pretty constant, but the current is about 1.1A for three seconds and then .1 amp for about 5 seconds once it gets warmed up.  Obviously, there's enough heat for the five seconds to continue to make smoke until the heater kicks in.  This is normal operation, and the fan runs all the time.  The units I have are pulls from a 3rd Rail Diesel.

Here's the previous thread on these smoke units: Weaver smoke unit wiring question

I looked at the unit and there is no jumper. At the smoke unit there is a plug for the resister and the thermistor, the motor has wires to the board that is mounted on the frame of the loco.

I thought I would try something simple.  I reprogramed the R2LC to the 8 setting and the smoke unit is working correctly.  Leads me to believe that atlas did not check the operation of the unit.

WOW, I totally spaced out on that, obviously it was programmed for a strobe light, makes perfect sense now.

Thanks for your input, I always like hearing from you. Bill