Other than adding a bunch of cars and cranking up the voltage has anybody come up with a method to increase smoke output on a mike jr at slow speed? I like slow chugging with big smoke rather than high speed train racing...
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Use a few pairs of diodes, wired with polarity reversed for each pair, to drop the power to the motor vs. the smoke unit. They are wired in series with the one motor lead. This gives you more power as the smoke unit for the same speed.
Also, you can replace the smoke resistor on that unit with a 22 or 20 ohm smoke resistor for more heat at lower voltages.
When mine gets resurrected, I will be adding the Tender Light, possible marker lights and will work on the smoke unit. GRJ, if you could, tired I guess and can;t seem to be able to visualize the diodes in the motor circuit. If you could, please provide a rough diagram, no hurry...
Thanks!
Dale H has written on this topic several times, here's Dropping Voltage with Diodes
Unless you have a really large locomotive with lots of load, you can probably easily use 3A diodes and they'll be a lot smaller. Each pair will drop the motor voltage around .7 volts, depending on load and the specific diode characteristics. You'll find that higher voltage rated diodes may drop the voltage a bit more, probably a good thing in this application. I tried a 1N5401 diode with a .5A load and got .75V drop, with a 2A load, it increased to .82V drop.
john is this a puffer unit or fan driven?
Good point, that one has the plastic self-contained smoke unit, I haven't tried to "improve" one of those. The diode trick will still work for sure.
My PRR Mikado Jr 6-11100 has the puffer unit with the piston.
I have a prr mikado jr. and the smoke unit keeps shorting out. the first time I sent it back to lionel and the second time I took it to wild Bill's and this time I don't know if I should try to get it fixed
I got the wrong listing, yours appears to be the more "standard" one with the piston and cap like many of the post-war models. It's listed as a 20 ohm unit, which sounds a bit odd, I though most of those were 27 ohm units.
Originally Posted by Steelie:
I have a prr mikado jr. and the smoke unit keeps shorting out. the first time I sent it back to lionel and the second time I took it to wild Bill's and this time I don't know if I should try to get it fixed
How does it keep shorting out? What is the effect you see?
John,the first time I just notice it stopped smoking,the second time it stopped dead in it's tracks restarted it everything work fine but the smoke unit didn't come back on,and the third time it just stopped smoking again after making it through about 1hr of run time. ps I have to get ready to go to work 1:50
I can't imagine what is happening that can't be chased down, it's a very simple circuit and smoke unit!
Best bet for my money: install ERR cruise. It'll run better and smoke better. Too well, actually - I normally leave the smoke off.
Well, I'd chase down the reason the smoke craps out, that likely won't change by changing the electronics won't fix it. Also, if this is a TMCC locomotive, you'd be changing the DCDR for the Cruise Commander M, that won't change anything about managing the smoke.
john if its like the post war unit..then he can enlarge the hole think 1/8...thats what Alex did..remember his video on it.. man it smokes pretty good for a postwar style unit..
also, the pivot wears out and the amount of lift in the piston is diminished greatly. a little squeeze of the pivot hole (actually a split loop) will help tremendously
Both good suggestions, but if it's totally crapping out, I think he needs to address that first. 
Hello, just looked for repair paperwork but must have tossed it. I'm pretty sure they changed a board rcl2 or something like that,and the smoke unit for sure on the engine.It does have tmcc 6-38616 great engine. wild Bill's charge me around 10.- bucks to fix it last time,maybe a wire rubbing on something,I"ll mention it the next time I make run up to wild Bill's
