Greg, I have a few fan driven Aristo units. But they keep shutting down on me. I even sent 2 back for replacement, before Aristo dried up and blew away. I like fan driven units, but I cant fit them into some of my equipment.
The electronics in the Aristo units fail, but I use “direct smoke”, so I bypass the electronics. All my locos have DCC decoders that do “direct smoke”.
Greg
Greg, the electronics detect fluctuations in voltage and react as if the unit is out of fluid. If I clean the track real well, and the wheels and pick ups, the Aristo unit will smoke for a whole lap of my railroad before shutting down. Any dirt and the darn thing will shut down in 5 to 10 feet.
I tested this on my workbench. When connected directly to a power supply they run fine. But when I connect one terminal of my power supply to a rail, and slide a wire along the rail to power the smoke unit, it shuts down. I was thinking of adding capacitors to the smoke unit right after the smoke unit’s rectifier diodes to smooth out these fluctuations.
It’s actually more complex than that David.
The basic flaw is that it is run by a microprocessor that resets easily, and the “detection algorithm” appears to be that it runs wide open when started, and then looks for a variation in current drawn, although I believe it is looking at voltage.
So any interruption and it resets the detection algorithm. Also at voltages about 5-7 volts the unit pretty much resets over and over.
Now this is for a perfectly functioning system. Any intermittents also cause problems, like the connections to the heater, which are metal caps pressed on the ends.
Another cause is that the design gets the board “wet” and the fluid eventually destroys the electrolytic capacitors, or causes them to pull on the board and damage connections.
Also the unit does not use a high voltage/current on the heater by design, so if it is smoking really well, then the circuitry is damaged and will die soon. The normal symptom is the “supersonic fan”, signalling the voltage regulation has gone to hell.
You could do what you say, but because it draws 1/2 amp, you need a BFC to make it work.
Greg
BFC must be a Big Farad Capacitor, or better known as super cap. He HE HE.
The trouble I’ve had with Aristo units is fluid gets on the board and the aluminum capacitors don’t like that. The rubber plug swells and pulls the part clear off the board. The symptom is, it smokes for a couple minutes, then turns off. You can cycle the power and it will work for a couple minutes more.
Hmm. Maybe I’ll try Greg’s technique of bypassing the electronics. It’s here in one of these boxes somewhere.
I would like to know more about how to modify those units so they work. I mean, if I take the fan, and the heater element, and wire a regulator (placed external to the unit) and just bypass all the Aristo wiz bangs, would that work? Would that work better?
Greg Elmassian said:
It’s actually more complex than that David.
The basic flaw is that it is run by a microprocessor that resets easily, and the “detection algorithm” appears to be that it runs wide open when started, and then looks for a variation in current drawn, although I believe it is looking at voltage.
So any interruption and it resets the detection algorithm. Also at voltages about 5-7 volts the unit pretty much resets over and over.
Now this is for a perfectly functioning system. Any intermittents also cause problems, like the connections to the heater, which are metal caps pressed on the ends.
Another cause is that the design gets the board “wet” and the fluid eventually destroys the electrolytic capacitors, or causes them to pull on the board and damage connections.
Also the unit does not use a high voltage/current on the heater by design, so if it is smoking really well, then the circuitry is damaged and will die soon. The normal symptom is the “supersonic fan”, signalling the voltage regulation has gone to hell.
You could do what you say, but because it draws 1/2 amp, you need a BFC to make it work.
Greg
Interesting to read explanation Greg , and quite understandable .
Mike
Thanks Mike, did quite an investigation a while back, actually tested 27 Aristo units between a friend and I.
We started off because no one could agree on the reservoir size, not even people in the employ of Aristo.
Tom, since the microprocessor resets at every power interruption, most units will run somewhat for about 5 minutes. Now if the caps are destroyed, other things may happen, usually the regulation goes to hell, and track voltage is applied to the fan and/or heater… everything looks great, for a while, as the unit prepares for meltdown.
David, you can run the fan on regulated 5 volts… but the heating element is a wild card, because you want to monitor current… that said, the aristo heating elements will usually work ok about 9 volts without destroying anything.
NOTE WELL: “usually”… heaters with lower resistance will heat excessively and melted plastic and other bad stuff can happen.
You can get pretty close to drawing an amp through the heating element at higher currents, so you will need a regulator with a heat sink…
Greg
Greg, and what current should the heating element be at?
Hah! it depends!
That’s the rub, you are trying to maintain an even temperature.
You may just have to experiment, I kind of do it by eye, and feeling the temp of the housing…
(actually I measure the housing temp and make sure it heats to a point and stops)
this is not just a plug and play, that’s why the Aristo unit measured the current, moreover, it watched the variation in current to know when the wick went dry.
Try picking a voltage that gives you 1/2 amp draw on the heater alone and see if the smoke volume is adequate.
Greg
Ok, so if I set up a current regulator for 1/2 amp, that should work?
yeah that would be pretty good… if you make a nice inexpensive circuit, a number of people may be interested.
Greg