I have stayed away from DCC partly because I did not understand it, partly because I did not want to complicate things, partly because of the extra expense. Now I understand the very clever principle behind it and am not so against it. I still have no experience with DCC and own no DCC equipment. The point is that while reading about it I read that running a DCC loco on DC could be damaging and wondered if perhaps my Aristo-Craft 2 8 8 2 mallet could have a DCC decoder installed without me knowing it. I prefer not to disassemble it unnecessarily. Hence the question. Can one know if a locomotive is equipped with a DCC decoder without disassembling it?
Can one know if a locomotive is equipped with a DCC decoder without disassembling it?
trainstrainstrains
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I have stayed away from DCC partly because I did not understand it, partly because I did not want to complicate things, partly because of the extra expense. Now I understand the very clever principle behind it and am not so against it. I still have no experience with DCC and own no DCC equipment. The point is that while reading about it I read that running a DCC loco on DC could be damaging and wondered if perhaps my Aristo-Craft 2 8 8 2 mallet could have a DCC decoder installed without me knowing it. I prefer not to disassemble it unnecessarily. Hence the question. Can one know if a locomotive is equipped with a DCC decoder without disassembling it?
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You will not damage a DCC decoder-equipped loco if you run it on DC. One of two things will happen - either it will simply do nothing (while not being damaged in any way) or it will function normally. The DCC standards are very clear on that fact. A DCC decoder is supposed to be able to safely tolerate DC track voltage suitable to the scale (20+V DC would fry a Z scale decoder designed to have 9V, but not a large scale decoder designed to handle that voltage).
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Going back to the title of your topic, That is a good question.
I too am curious in that I have some locomotives that I am no longer sure if they do or do not have a decoder in them. How can one tell easily if there is or is not decoder in a locomotive?
Jerry
I too am curious in that I have some locomotives that I am no longer sure if they do or do not have a decoder in them. How can one tell easily if there is or is not decoder in a locomotive?
Jerry
Whilst it shouldn't damage the electronics, it's worth being aware that a DCC decoder fitted loco can sometimes be "confused" by PWM pulsed DC (eg. the orange Aristo Basic Train Engineer or the black TE when NOT set to linear mode). This could lead to erratic operation unhealthy for the gearing.
I've seen such behaviour in N scale locos - a decoder fitted loco was once tried on my layout which uses PWM controllers and the loco wasn't happy. Yet other chipped locos have been fine, so I guess it depends on the decoder?
One of my older Aristo locos has an NCE D408 decoder fitted which I recall didn't behave well with PWM, but I didn't try it for very long.
I've seen such behaviour in N scale locos - a decoder fitted loco was once tried on my layout which uses PWM controllers and the loco wasn't happy. Yet other chipped locos have been fine, so I guess it depends on the decoder?
One of my older Aristo locos has an NCE D408 decoder fitted which I recall didn't behave well with PWM, but I didn't try it for very long.
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Just what he said, put it on a programming track.
You can buy a complete 3 amp pro grade system (NCE) for $143, that can be upgraded to 5 amps.
Greg
You can buy a complete 3 amp pro grade system (NCE) for $143, that can be upgraded to 5 amps.
Greg
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If you have a linear power supply, try setting the loco on the track and very slowly applying voltage to the rails. Watch the voltage and watch the wheels and lights. If the loco is DCC equipped, the voltage will have to raise to a certain point before the electronics that control the loco "wake up" and begin to operate the motors, lights, sounds, etc. That's typically around 6 volts give or take, but that depends on the specific decoder. If the loco's lights come on or the motors start moving with only 2 or 3 volts, then chances are good it does not have a DCC decoder onboard.
(If the loco has skates or tender pick-ups, raise the loco off the track and use the skates or tender to supply power. The motors will begin to turn on lower voltages if they're not supporting the weight of the loco.)
Later,
K
(If the loco has skates or tender pick-ups, raise the loco off the track and use the skates or tender to supply power. The motors will begin to turn on lower voltages if they're not supporting the weight of the loco.)
Later,
K
Pardon my ignorance, I have no DCC equipment to try this on nor do I follow it's architecture, but...
If one were to put an ohmmeter on the wheels of a DCC-equipped engine, wouldn't one expect a substantially different value than one gets with a simple track powered engine?
If one were to put an ohmmeter on the wheels of a DCC-equipped engine, wouldn't one expect a substantially different value than one gets with a simple track powered engine?
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Maybe Todd, the first thing the track pickups go into is a full wave bridge, and a filter cap.
Since some people use FETs instead of diodes, measuring with an Ohmmeter will most likely not give you definitive results, you could show a low resistance like a motor by going through the bridge and an uncharged electrolytic filter cap.
Also, there could be a diode string and a sound card in the loco.
Nope, the only way and easy way is a DCC programming track. Otherwise, if you cannot spare $143, open it up.
Now in this specific thread the OP asks about a 2-8-8-2 mallet... it's just a couple of minutes to pop open the tender if a late model (hmm, did they upgrade the mallet like the Mikado and Pacific?), and only a few screws to pop off the boiler to look inside.
If you have one loco, open it up. If you are going to be in this situation a lot, like buying trains and don't know what's inside, invest the $143.
Greg
Since some people use FETs instead of diodes, measuring with an Ohmmeter will most likely not give you definitive results, you could show a low resistance like a motor by going through the bridge and an uncharged electrolytic filter cap.
Also, there could be a diode string and a sound card in the loco.
Nope, the only way and easy way is a DCC programming track. Otherwise, if you cannot spare $143, open it up.
Now in this specific thread the OP asks about a 2-8-8-2 mallet... it's just a couple of minutes to pop open the tender if a late model (hmm, did they upgrade the mallet like the Mikado and Pacific?), and only a few screws to pop off the boiler to look inside.
If you have one loco, open it up. If you are going to be in this situation a lot, like buying trains and don't know what's inside, invest the $143.
Greg
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I have opened the tender and this is what is inside; a Sierra Sound card that works, a speaker , a rechargeable battery that I have replaced successfully with supercapacitors, I have learnt to program the card but the steam sound is very difficult to synchronize so I'm planning on synchronizing the sound to a driver. The loco starts moving at about 2 volts. The Loco has 2 cables with connectors as seen on the photo.
There is also evidence that it was very probably run on batteries, because the person who sold it was also selling an aristocraft stock car with 3 heavy batteries installed.
Is this sufficient to know there is no Decoder or should I open the boiler? Greg. Which are the few screws to pop off the boiler to look inside?
There is also evidence that it was very probably run on batteries, because the person who sold it was also selling an aristocraft stock car with 3 heavy batteries installed.
Is this sufficient to know there is no Decoder or should I open the boiler? Greg. Which are the few screws to pop off the boiler to look inside?
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When I place a DC loco on my DCC track, several observations I have:
Front and rear lights come on.
Motor has buzzing sound.
No need to try and read any addresses as this tells me it is DC only.
Front and rear lights come on.
Motor has buzzing sound.
No need to try and read any addresses as this tells me it is DC only.
But why risk damaging a non-chipped loco by putting it on a DCC track? If you have anything other than the most basic entry level DCC system you're almost definitely going to have a programming track capability, and it's simple to try reading the address.
Yes MOST locos can survive and indeed as we know some DCC systems support control of an unchipped loco, but it's really not good for the loco in the long term. Certain Piko locos have been known to blow their interference suppression capacitors in very short order when subjected to DCC.
Personally I would refuse to put a loco on a DCC track without knowing for sure it has a decoder.
Yes MOST locos can survive and indeed as we know some DCC systems support control of an unchipped loco, but it's really not good for the loco in the long term. Certain Piko locos have been known to blow their interference suppression capacitors in very short order when subjected to DCC.
Personally I would refuse to put a loco on a DCC track without knowing for sure it has a decoder.
This is exactly what I was thinking.
So how about some measurements to substantiate or refute your thinking?
I would think that you have a whole stable of these things around and your curosity would have peaked. I know mine would have.
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Huh? What is your problem? What's with the agressive crap out of left field?
I don't have to substantiate or refute squat to you.
Yes I do have a whole stable of these AND several DCC systems and I can open a loco, so why would I spend time trying your method, when I have better, simpler, easier methods that do not have to depend on a theory?
jeeze Todd
Greg
I don't have to substantiate or refute squat to you.
Yes I do have a whole stable of these AND several DCC systems and I can open a loco, so why would I spend time trying your method, when I have better, simpler, easier methods that do not have to depend on a theory?
jeeze Todd
Greg
Isn't the situation mostly the other way around?
People have a DC layout, buy a loco on ebay or wherever, want to know if there is a decoder inside without having to open the loco.
That was ttt's situation the way I read it.
Because you didn't think of this, I'm being agressive?
You're not doing it for me. You would be doing it for others on the forum who are looking for a quick easy method to make a differentiation. I have no dog in this fight.
jeeze
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uhh... a little reading.
1. the situation is he has no DCC system, see quote below.
2. I would never try to use an ohmmeter on the track pickups, too many other things could be connected to the track pickups
3. I'm not upset that I did not think of using an ohmmeter just like I'm not upset trying to drive a car with a package of noodles
4. I did not suggest the ohmmeter test, Todd did.
5. likewise I do not need to "refute or substantiate" #4, because I don't think it is a good test
6. "piqued" and "curiosity" , not "peaked" interest Todd. " curosity would have peaked."
7. Yes Knut, you clearly read the thread and thought it through.
Regards,
Greg
1. the situation is he has no DCC system, see quote below.
2. I would never try to use an ohmmeter on the track pickups, too many other things could be connected to the track pickups
3. I'm not upset that I did not think of using an ohmmeter just like I'm not upset trying to drive a car with a package of noodles
4. I did not suggest the ohmmeter test, Todd did.
5. likewise I do not need to "refute or substantiate" #4, because I don't think it is a good test
6. "piqued" and "curiosity" , not "peaked" interest Todd. " curosity would have peaked."
7. Yes Knut, you clearly read the thread and thought it through.
Regards,
Greg
toddalin said:
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Thanks everyone.
Any comments on permalink No.10 will be much appreciated.
Any comments on permalink No.10 will be much appreciated.
I guess that it was just too much effort for Greg to simply put an ohmmeter across the wheels on a DCC engine and report back.
None the less, we had a Club meeting tonight and one of the guys runs DCC. He also thought there should be an obvious difference when read with an ohmmeter and said he would give it a try and report back to me. I hope he remembers because with ~50 people there tonight, I'm having a hard time remembering who it was.
Alternatively, there are probably several here would could perform this little test and let the group know the outcome.
None the less, we had a Club meeting tonight and one of the guys runs DCC. He also thought there should be an obvious difference when read with an ohmmeter and said he would give it a try and report back to me. I hope he remembers because with ~50 people there tonight, I'm having a hard time remembering who it was.
Alternatively, there are probably several here would could perform this little test and let the group know the outcome.
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