DCC AND SMOKE UNITS

[TONYWARD50]

Having chipped about 9 locos I now feel reasonably comfortable at tackling some more but I have not hit upon a suitable method of wiring smoke units.
I can (sometimes) wire a unit to switch on or off through F4, say, on a Loksound XL Decoder but that means it tends to go full blast or not at all.
Aristocraft locos and some USA locos have a smoke unit which is also fan-controlled.
Someone said you could use a relay to make these work but I feel I may be getting out of my depth.

Could anyone explain in words, and diagrams, if possible, what I need to do and how I do it ?

 

[Neil Robinson]

All a relay would do is permit a small current source, such as a function output of a decoder, to switch a high current drain item, such as a relatively high power smoke unit, on and off.
I suspect from your post that you are dissatisfied with the "full blast or not at all" operation.
I am aware that some factory fitted units, such as those in the MTH Railking Gauge 1 steamers, have fans that modulate the smoke to match the sound. I also know that Massoth developed an after market fan assisted smoke unit to go with their sound decoders. These are in two versions, 5V and 19V, and the 5V ones proved unsatisfactory with decoders due to the high current drain.
May I suggest you investigate their 19V version as one possible way to go?

 

[TONYWARD50]

Thanks for those wise words and I may well have to do just that. However, id there not a away I can use the existing Aristo fan-driven units ?

 

[muns]

I have one of the Massoth 19v smoke units linked to a Massot XS decoder in my HSB 2-6-2 (99-6001) - works a treat.

 

[AlanS]

I have found that Aristo smoke units perform well when wired direct to F1 on Massoth decoders although as you say they only perform on full blast.
USA trains need to be left wired through the original PCB which I tend to do but rarely bother to use as it is a pain to stop and start locos and "fiddle" about underneath for the correct switch every few minutes to switch on and off as required.

 

[rjstott]

New to Forum and have to admit I haven't tried this but why not set the output to a flash mode. Depending on the flash you can certainly get 50% power reduction. Alternately you can set the brightness for most outputs and so select a level you are happy with. ESU decoders have a mode for Smoke Generators described as allowing the smoke intensity to be changed but the manual I have isn't clear whether you can link this to speed or some similar parameter.

There is a warning about the current limitation of the decoder!

Let me know if you get a suitable solution.

 

[Jon]

Decoder chips often have limited current capacity hence use 19 or 24 v smoke units that need a far lower current than the 5v units. Output can be controlled on Massoth unit by altering CV to reduce output voltage, hence smoke volume. I have used the massoth 19v pulsed smoke unit - effective but pricey!
Jon

 

[laney]

Been reading through this old thread - is it normal then for the smoke units not to work properly after the loco's been chipped??:thinking:

 

[ntpntpntp]

Been reading through this old thread - is it normal then for the smoke units not to work properly after the loco's been chipped??:thinking:

The problem with smoke units, as you'll have read in this thread, is that the current they tend to require is typically more than the function output of a decoder. Most cases some sort of relay or power transistor is needed in between the function output and the smoke unit power supply. For factory fitted decoders that may well be built in. For user fitted decoders it's up to the fitter to sort it out.

Personally I don't bother trying to get the smoke unit to work via a DCC function, I just leave it wired directly to the track via the original smoke on/off switch. For a steam loco I don't think it's so important, as once lit I imagine the fire going all day and it wouldn't seem right just switching it on and off! The only time this arrangement might bother me is if I had a diesel loco with sound as then I'd probably want the smoke on/off to be related to engine startup & shutdown sounds.

Nick

 

[stockers]

Been reading through this old thread - is it normal then for the smoke units not to work properly after the loco's been chipped??:thinking:

Not at all, it just that with some chipping its necessary to consider what the smoke unit is doing - power wise.
With all more recent LGB (with decoder ready stickers or DCC interface), you just add the decoder and the original circuit board deals with the power/voltage issue. The problem comes when you have to re wire the loco and dispose of existing circuit boards. This is not a problem in its self as most decoders (i'm thinking Massoth ) can deal with all the wiring for motors, lights, smoke etc. the issue comes from the power (amps) needed to run smoke units.
As has been said above, you can wire the unit straight to the decoder with a 19 or 24 volt unit and it should all work pretty well. The problem comes with the 5 volt unit. as voltage goes down, current goes up and the decoder switching cant really take this load from a 5 volt unit. So there are a few options which sound confusing when they all arrive peicemeal in a thread like this - I will try to explain (but I'm no real expert - just a user).

MTS track is 24 Volts, so one way is to wire a new 24 volt unit direct to the wheel pick-ups. It is always on and wont work well on analogue unless you go fast.
Wire a 18/19 volt unit to the decoder and CHANGE THE DECODER OUTPUT TO 19V. This will smoke on analogue when the track voltage approaches 19V. You are still putting quite a bit of power (amps) through your decoder though but it should ? take it.
Fit an intermediate 5V voltage regulator (avaialable from decoder makers) and switch this from the decoder but power it from the wheels.

As you can see, its all a bit fiddly, especially to the beginner, but can certainly be done.

I am sure some others here can fill in the gaps in my reasoning.