# Model power, N scale three light signal #8572



## G1-L Tech (Dec 7, 2016)

Can anyone explain to me how the blue blazes this thing hooks up? It's the Model Power #8572 three light signal, it comes with a four way pre wired switch. It's says all you have to do is hook up the black and brown wire, boom, done, not in this case, so, either I'm doing something wrong or I can't follow simple instructions. I have power, checked with meter, now, there is a resistor on the switch for the brown wire, and a blank terminal on the switch, it looks like it's labled DC. The 'instructions' that came with it are REALLY vague.....can anyone help? Thanks
:dunno:

Trev


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## traction fan (Oct 5, 2014)

*Signal wiring*



G1-L Tech said:


> Can anyone explain to me how the blue blazes this thing hooks up? It's the Model Power #8572 three light signal, it comes with a four way pre wired switch. It's says all you have to do is hook up the black and brown wire, boom, done, not in this case, so, either I'm doing something wrong or I can't follow simple instructions. I have power, checked with meter, now, there is a resistor on the switch for the brown wire, and a blank terminal on the switch, it looks like it's labled DC. The 'instructions' that came with it are REALLY vague.....can anyone help? Thanks
> :dunno:
> 
> Trev


Trev;

I'm not familiar with this particular product, but the four wires you mentioned are probably set up something like this. One for red, one for yellow, one for green, and one common wire that connects to all three lamps, or LEDs. That's an important point, does your signal use incandescent lamps (most likely) or LEDs (Light Emitting Diodes) (less likely, but possible.) You mentioned that "The directions said to hook up the two brown wires." What did they say to hook those brown wires to? The track, with one brown wire connected to each rail? If that's the case then I think the signal contains 12-18 volt incandescent lamps rather than LEDs.

I suggest ignoring the Model power 4-way switch for the moment, and testing just the signal itself. First use your meter to measure the resistance of two lamp wires. Try the same two wires with the meter leads reversed. An incandescent lamp will show the same measurable resistance in either lead orientation. An LED will read a low resistance in one direction and a high resistance in the other. If you get zero resistance on that pair of wires try one different wire with each of the first wires separately. You should eventually be able to determine which wire feeds the red, yellow and green lights, and which is common to all three. ( I'm assuming here that Model Power's "directions" don't bother to actually tell you which wire is which. If they do, then this wire mapping process wont be needed. 

Once you have the wires mapped out, let's try lighting something up. Use a 9 volt battery and a 67 ohm (approx.) resistor to test one light. Try hooking the resistor to the common wire and one of the three light wires. If something lights up great, if nothing does try reversing the battery connections to the same two wires. If that lights one color light up then your signal does have LEDs. They are polarity sensitive, and only work one way, with the correct polarity. Incandescent lamps don't care about polarity, they will work either way. 

NOTE: This next test should ONLY be done if you have determined, with your meter resistance measurements, that the signal DEFINITELY HAS INCANDESCENT LAMPS. LEDs will burn out instantly without the resistor!

If the lamp just barely lights up very dim, then remove the resistor and run the lamp straight off the 9 volt battery. If that lights it up brighter, the lamps are probably intended for 12-18 volts, but will last longer on 9 volts. 

I know nothing about the Model Power switch. However the electricity isn't complicated. The signal's common wire is always connected to the battery. Each of the other three wires can alternately be connected to the battery's other terminal to turn on one of the three lights, red, yellow or green. Any electrical switch that does this; rotary switch, 4 position slide switch, etc. will operate the signal. The Model Power switch must be set up to do the same thing electrically, but I can't advise you on specifics since I've never seen that switch.

good luck;

Traction Fan:smilie_daumenpos:


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## G1-L Tech (Dec 7, 2016)

Thank you Traction Fan, I will try the resistance test, they are led lights, and I do believe that you are correct in saying that the wires are red for red light,yellow,...etc. I did, however get another signal and hooked it up, it work right away, so I'm thinking that the first one has bad LEDs, or I somehow managed to short them and burn them out. 
Thanks again for your response and wiring knowledge, you have been very helpful.
Trev


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## traction fan (Oct 5, 2014)

*Bad LEDs?*



G1-L Tech said:


> Thank you Traction Fan, I will try the resistance test, they are led lights, and I do believe that you are correct in saying that the wires are red for red light,yellow,...etc. I did, however get another signal and hooked it up, it work right away, so I'm thinking that the first one has bad LEDs, or I somehow managed to short them and burn them out.
> Thanks again for your response and wiring knowledge, you have been very helpful.
> Trev


Trev;

Did you at any point, connect the signal's brown wires, or any other wires, to the track? That would have put 18 volts or so through the wires and whatever they are connected to. If you are certain that the signal has LEDs rather than incandescent light bulbs, remember that the LEDs need to have DC power applied through a resistor (which limits the current through the LEDs, and preventing them from burning out.) and the DC power needs to be in the correct polarity. If a light does not work, try reversing the wires. A good LED should have some (low) resistance in one direction and a very high resistance in the other direction (when you reverse the wires) If an LED is actually burned out, it will measure infinite resistance in both directions. If all three lights are not working then there may be some open connection in that 4th, common, wire. It's the only one that could knock out all three lights.
Is your signal new enough that you can return it and get a working replacement? If so I'd do that rather than trying to fix the dud signal.

good luck;

Traction Fan:smilie_daumenpos:


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## G1-L Tech (Dec 7, 2016)

I checked everything,......low and behold, I'm an idiot. I somehow managed to short the terminals on the switch, you can see where, somehow, it touched the rails, (probably because I am a clutzy ogre), the burn marks. So to sum it up, thank you traction fan for everything, but in the end, I'm nothing but a big dumb ox!
Trev


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## traction fan (Oct 5, 2014)

*20(+ + + +) mule/ox team*



G1-L Tech said:


> I checked everything,......low and behold, I'm an idiot. I somehow managed to short the terminals on the switch, you can see where, somehow, it touched the rails, (probably because I am a clutzy ogre), the burn marks. So to sum it up, thank you traction fan for everything, but in the end, I'm nothing but a big dumb ox!
> Trev


Trev;

I'm glad you were able to find the problem. As for being "a dumb ox"; you are not alone! I'll bet everyone here has been "a dumb ox" at one, or more, times in their life. I know I have, because my wife keeps a "dumb husband list" of the various instances! :laugh: After 37 years of marriage, you can guess how long the list is! 

don't sweat it;

Traction Fan :smilie_daumenpos:


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