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Really stupid newbie question about DCC wiring

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  • Member since
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Posted by richg1998 on Sunday, March 2, 2014 10:37 PM

Something just came to mind about troubleshooting DCC wiring. If you start at the track where the loco is with the meter, work backward to the panel. You will see the point where you have a poor connection.

 You can start at the panel and work toward the loco if you prefer.

 You should check at the panel where the wires are in the plug.

 I am assuming the LED is at the proper intensity which would indicate about 13.5 VAC.

The LED in the panel shows the DCC signal is active. The LED is connected right across the two DCC leads with a 1k resistor. I checked mine very carefully.

Rich

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Posted by 88gta350 on Sunday, March 2, 2014 10:30 PM

Okay, I soldered 14 gauge bus wires directly to a piece of spare flextrack and got 14.6V on the track.  Tried my locomotive and it worked!  So I guess I just need to work on my wiring connections.  That seems to be the problem.  Thanks to everyone who weighed in.

Dave M
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Posted by richg1998 on Sunday, March 2, 2014 9:47 PM

The six pin item is a DC adapter. My Bachmann locos came with them. The diagram page show how the adapter is used in place of the decoder.

 I have the Power Cab and my four meters show about 13.4 VAC. The power supply for the Cab is rated at 13.5 VDC and the DCC signal should be about the same potential.

 With a poor connection, there will be resistance at that point which will drop the voltage some because the decoder is drawing current and the voltage is not hight enough for the decoder to operate correctly. Right now I am assuming the meter is correct. A load that could drop the voltage that much would trip out the Cab.

 Take two pieces of wire from the panel right to the track just to prove a point. I have double clip leads to do this. A couple pieces of bare wire at the panel and the clip leads from those two wires right to the track.

When the loco can operate, the Cab will show how much current the decoder is drawing. Check your manual.

 Rich

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Posted by 88gta350 on Sunday, March 2, 2014 9:18 PM

My locomotive is supposed to be equipped with a decoder, however there is a small 6 pin circuit board in the box, smaller than the size of a dime. This is the only engine I've ever bought with DCC so I'm not familiar with what that part is.  The Bachmann instructions are no help but they do indicate the loco is already equipped with a decoder.

I do get a digital display on the PowerCab and it's addressed to 3.  When I hit the "program" button it says "can not read CV" which the NCE manual indicates means the decoder is not responding.

Dave M
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Posted by CSX Robert on Sunday, March 2, 2014 9:10 PM

cacole
...If you're trying to run a locomotive that you know is DCC equipped and it has never been previously ran under DCC control, it should be on address 3.  So press the SELECT LOCO button, enter address 3, and try again...

Also, make sure you just enter '3', and not '0003' because they are not the same address.

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Posted by cacole on Sunday, March 2, 2014 8:32 PM

Are you getting a digital readout on your PowerCab screen?  

If you're reading an AC voltage on the track and the locomotive is not moving, it may not have a decoder!  Only a locomoitve with a DCC decoder can be used with the PowerCab.

As far as your voltage reading is concerned, you should be getting a reading of around 14.5 Volts AC with your meter set on the 20 Volt range, without the locomoitve on the track.  With a non-decoder equipped locomotive on the track, the headlight should come on if it is not burned out.

Your low voltage reading of 8 to 8.5 VAC could be caused by the suitcase connectors not making good contact if you still have them in the circuit.

If you're trying to run a locomotive that you know is DCC equipped and it has never been previously ran under DCC control, it should be on address 3.  So press the SELECT LOCO button, enter address 3, and try again.

All of this is in the PowerCab manual, so you need to sit down and read it.  Start with the setup instructions and make sure everything is right, then go to the Troubleshooting Section in the back of the book.

 

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Posted by DigitalGriffin on Sunday, March 2, 2014 8:17 PM

Simple answer: Either way is fine.

Don - Specializing in layout DC->DCC conversions

Modeling C&O transition era and steel industries There's Nothing Like Big Steam!

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Posted by 88gta350 on Sunday, March 2, 2014 8:01 PM

gregc

sorry ... AC.    I measured 13.8 AC

 

 

I'm getting 8.0-8.5V AC.  Is that indicative of a wiring connection problem?

Dave M
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Posted by gregc on Sunday, March 2, 2014 7:16 PM

sorry ... AC.    I measured 13.8 AC

greg - Philadelphia & Reading / Reading

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Posted by gregc on Sunday, March 2, 2014 7:13 PM

88gta350
I'll take a multimeter to the track to see if it has power.  What should I see?

it's a pulsed signal.   I'm guessing something > 8 and < 14V DC  AC.   not zero

greg - Philadelphia & Reading / Reading

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Posted by 88gta350 on Sunday, March 2, 2014 6:41 PM

gregc

 

 
88gta350
I attached track bus wires to the two-place connector that attaches to the circuit board, attached my throttle to the port via the included "phone" wire, and plugged it into the wall.  I got power to the throttle but the LED indicating power to the track did not light up and when I put a locomotive on the track there was no indication of power getting to it.

 

Presuambly you connected things as shown on the left side of the image below.  all you need are two wires connected from the NTP to a section of track (keep is simple).

you must plug your power can into the left connector (oriented as below).   When i plug my power cab into the right connect, the power cab turns on but the LED never does.

when i properly plug my power cab into the left connector the red LED comes on after several seconds (~7).   If there is a short, the LED starts to light up and then everything turns off and the cycle repeats.

 

and edit you original post and replace "stupid"

 

 

Yes, I've got it hooked up correctly now and the red LED is lit, but when I put a loco on the track it does nothing.  I'll take a multimeter to the track to see if it has power.  What should I see?

Dave M
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Posted by gregc on Sunday, March 2, 2014 6:06 PM

88gta350
I attached track bus wires to the two-place connector that attaches to the circuit board, attached my throttle to the port via the included "phone" wire, and plugged it into the wall.  I got power to the throttle but the LED indicating power to the track did not light up and when I put a locomotive on the track there was no indication of power getting to it.

Presuambly you connected things as shown on the left side of the image below.  all you need are two wires connected from the NTP to a section of track (keep is simple).

you must plug your power can into the left connector (oriented as below).   When i plug my power cab into the right connect, the power cab turns on but the LED never does.

when i properly plug my power cab into the left connector the red LED comes on after several seconds (~7).   If there is a short, the LED starts to light up and then everything turns off and the cycle repeats.

 

and edit you original post and replace "stupid"

greg - Philadelphia & Reading / Reading

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Posted by rrinker on Sunday, March 2, 2014 6:03 PM

 Sounds like either you are using the wrong cord - you need to use the flat one with the two heavier wires on the outside. That would result in the symptons you described - the cab powering up but no track power. And definitely has to be in the correct port on the panel, that too would cause the issue described.

            --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by 88gta350 on Sunday, March 2, 2014 6:03 PM

cacole

Suitcase connectors are probably the source of your problem, especially if you didn't crimp them tight enough or they are the wrong size for the gauge of wire you're using.

Also, make absolutely sure you have the PowerCab plugged into the LEFT socket on the interface panel and that you're using the FLAT cord and not the coiled cord.

 

Well, that was the source of part of my problem.  I was using the coiled wire.  I even read it in the instruction booklet, but the flat wire was hiding in the box and I didn't even realize I had it and it didn't click when I read it that there should be two different wires.  I now have a red LED on the circuit board indicating power to the track, but a locomotive still shows no signs of getting power.

Dave M
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Posted by richhotrain on Sunday, March 2, 2014 5:50 PM

88gta350

I guess I could do the simplest thing possible and just wire a single piece of flex-track directly to the circuit board to make sure the components work.

 

Yes, do that just to eliminate any issue over a faulty Power Cab.  Then, if all works well, the problem is with the wiring connections.   The suitcase connectors could be your problem.  There are better ways to connect feeders to the bus wires.  How are your feeders connected to the rails?

Rich

Alton Junction

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Posted by cacole on Sunday, March 2, 2014 5:37 PM

Suitcase connectors are probably the source of your problem, especially if you didn't crimp them tight enough or they are the wrong size for the gauge of wire you're using.

Also, make absolutely sure you have the PowerCab plugged into the LEFT socket on the interface panel and that you're using the FLAT cord and not the coiled cord.

 

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Posted by 88gta350 on Sunday, March 2, 2014 5:26 PM

My layout is a little more complicated than a simple oval, but not much.  Right now I just have a small section of track down and before I got too far I wanted to make sure I understood how everything was supposed to work and, I admit, wanted to see a train move.  I have a track bus run under the track and connected one pair of feeders up to it to power this small section of track I have laid.

My DCC system is an NCE PowerCab.  Seems to be a very basic set-up.  I attached track bus wires to the two-place connector that attaches to the circuit board, attached my throttle to the port via the included "phone" wire, and plugged it into the wall.  I got power to the throttle but the LED indicating power to the track did not light up and when I put a locomotive on the track there was no indication of power getting to it.  I tried it with the bus wires making a loop under the layout and with them as single wires connected only to the feeder wires.  Unless my wiring connections are not good I don't know what the problem is.  I used suitcase connectors for all the wiring connections.  I guess I could do the simplest thing possible and just wire a single piece of flex-track directly to the circuit board to make sure the components work.

Dave M
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Posted by rrinker on Sunday, March 2, 2014 5:14 PM

 Just make sure all the black connects to the black rail and all the red connects to the red rail. Otherwise you will have a short.

                 --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by richhotrain on Sunday, March 2, 2014 5:05 PM

Neither way worked???

That's strange because either way should work.

What kind of DCC system?

Tell us more about how you wired the connection between the command station and the bus wires.

Rich

Alton Junction

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Posted by cacole on Sunday, March 2, 2014 4:58 PM

However is the easiest way for you.  On a single track oval, how many feeders you need is going to depend on how large an oval you're wiring, and whether you are using sectional track or flextrack.  Sectional track will require more feeders because of the numerous rail joints.  For an oval of 4x8 feet, as an example, 4 feeders should be adequate with flex track, and they can be 4 separate wires straight to the required location from a central power source.

 

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Really stupid newbie question about DCC wiring
Posted by 88gta350 on Sunday, March 2, 2014 4:36 PM

Let's say I'm wiring a simple oval for DCC.  I'm not sure how to run the track bus.  Can it be a simple straight-line wire or does it need to be a loop to complete a circuit?  None of the explanations I've seen really answer this very cleary and always just show track bus wires running from the power source directly to the rails, something like this:

But everything mentions a track bus wire with feeders but I'm not sure if it should look like this:

or this:

or something else completely.  I'm a little lost. My common sense tells me it can be a simple straight wire because the track is the circuit I need to worry about, but I wired up a small section of track I laid both ways and it didn't work either way.

Dave M

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