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Unable to find a DCC wiring short

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  • Member since
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  • From: Mpls/St.Paul
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Posted by wjstix on Wednesday, August 1, 2018 12:59 PM

Wiring can be wacky (or is it the person doing the wiring?). I had a long running problem with a reverse loop - nothing would trip the short indicator, but the DCC autoreverser wouldn't work, it just clicked back and forth. I tried several things (making sure the insulated track joiners were right, checking the wiring over and over etc.) Eventually I found out that on one of the three feeder pairs going to the reverse loop, one wire had been wired to the mainline track wiring instead of the reverse loop. So, when trains entered the loop in one direction, it was OK, but when the autoreverser snapped as it left the loop, it caused a short (but didn't trip the short indicator).

Once I fixed that wire (and adjusted the controller's short indicator to make it more sensitive) it worked fine...well, I did have to put in a new autoreverser since I burned out the old one.

Embarrassed

Stix
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Posted by hon30critter on Thursday, July 26, 2018 10:35 PM

rrinker
 One of the first things I built back when I first got DCC and was about to build my first DCC layout was one of those simple buzzers - battery, buzzer, and some clip leads. I buitl it, tested it - and never used it. For some it may help though, connect it to the bus in place of the DCC system (you don't want to be feeding voltage back in to the system) and the instant you connect a feeder croossed to the wrong bus it will sound off, I mostly avoided any issue by using the same color feeder as bus

Hi Randy:

I think that the fact that we are working in a club environment vs building a layout on your own makes the buzzer a very valuable tool. As the layout construction foreman I can only keep an eye on each individuals' work for a short period of time before I have to move on to the next person or team. It is not reasonable to ask them to check with me after every connection is made. The buzzer monitors their work for me.

We do have different coloured buses and feeders, but that has not prevented someone from connecting the wrong coloured feeder to a rail. Of course it had to happen when the buzzer was not connected to the track. Fortunately I was right there in that instance to catch the mistake, but as I said I can't watch every wire being installed.

The buzzer is by no means a comprehensive solution to avoiding wiring mistakes. We have had a number of feeders installed on one of the reverse loops that were the wrong colour, and then subsequently attached to the wrong bus. The buzzer would not have detected a short because there wasn't one. We would only have discovered the mistake when we went to hook up the PSX-AR reverse loop controller.

Dave

I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!

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Posted by rrinker on Thursday, July 26, 2018 7:18 AM

 That is a ridiculous number of tooggle switches and complete overkill. What's going to short, once the wiring is properly hooked up? Especially on a long straight section between turnouts. Unless some cosmic event suddenly makes palstic ties electrically conductive, ir's going to be a derailed loco (very obvious) or leaving somethign metal laying on the tracks (not always obvious Whistling ). That's one goood argument AGAINST twisting the bus. While it's not likely wires will rub together so much that it would wear through the insulation, the bus/feeder connections are another story. Properly dressed there should be no exposed wire - soldered connections should be covered in something like liquid electrical tape, and suitcase connectors shouldn;t have extra wire sticking out the ends. Still, it is best to keep the opposite sides at least a little separated so they don't touch. I do this by NOT soldering the two feeders directly across from one another. My last layout, I never even got around to insualting all the solder joints, and I ran trains for several years and never had a short - even if the bus wires did touch, the two bare spots where the feeders were soldered were still several inches apart.

 One of the first things I built back when I first got DCC and was about to build my first DCC layout was one of those simple buzzers - battery, buzzer, and some clip leads. I buitl it, tested it - and never used it. For some it may help though, connect it to the bus in place of the DCC system (you don't want to be feeding voltage back in to the system) and the instant you connect a feeder croossed to the wrong bus it will sound off, I mostly avoided any issue by using the same color feeder as bus - red and white for the bus, AND red and white feeders. And since my feeders were all connected to the rail joiners (EVERY rail joiner a feeder - perhaps overkill on my part, but I never had any stalling issues nor did I need to frequently clean track), unless I stuck the wrong one on when laying the track, I just connected white to white and red to red. Red and white are easier to distinguish in the less than ideally illuminated underside of the layout, compared to red and black.

 Work slowly and carefully. In the end, you should have bulletproof wiring. The club modular layout is wired in such a fashion, with nary a suitcase cooonnector in sight, plus the added use of Anderson PowerPole connectors on the end of each section, Despite frequent travel, repeated set ups and tear downs, and storage in an unheated building (in their transport trailers, but still, no form of climate control other than a roof to keep the rain off), they coontinue to work each and every time the layout is set up for display. Even the signal system is pretty near flawless, unless someone forgets to hook up the Loconet cable and skips over one of the controllers. Once set up, trains are always running, the biggest problem being someone dialing in the wrong address and wondering why their loco doesn't move. While someone way down at the other end is frantically grabbing their loco to keep it from plowing in to a bumper. Can't fix that one with better wiring.

                                      --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 SeeYou190 on Thursday, July 26, 2018 6:39 AM

richg1998
Now that you mentioned that Dave, some ohm meters have a tone alert when you get a short.

.

Be careful using the audible "continuity indicators" when using a DVOM.

.

Some of these are actually diode testers, which work a bit differently than checking continuity.

.

Some of these come on at fairly high resistances. My Fluke 88 comes on at about 150 ohms. This means they will beep continuity through switch machine motors, transformer coils, etc. This can be misleading.

.

I always use the Ohm Meter and look for less than 2 ohms when checking for continuity.

.

-Kevin

.

Living the dream.

  • Member since
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  • From: Southern Florida Gulf Coast
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Posted by SeeYou190 on Thursday, July 26, 2018 6:37 AM

I don't want to get too high on a soapbox here...

.

SoapBox

.

I believe EVERY electrical section should be wired through a hidden ON/OFF switch so it can be isolated for troubleshooting. This adds time to construction, but sure saves time down the road.

.

-Kevin

.

Living the dream.

  • Member since
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  • From: Western, MA
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Posted by richg1998 on Thursday, July 26, 2018 12:40 AM

Now that you mentioned that Dave, some ohm meters have a tone alert when you get a short. My Harbor Freight meters do. That position is separete from the resistance scale. I just tried it on my meter.

Even if no audio indicator, a visual zero ohms on a meter could be useful.

No model railroader should be without a multimeter today.

Radio Shack use to sell a buzzer. I had one some years ago but lost it in a move.

Rich

If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.

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Posted by hon30critter on Wednesday, July 25, 2018 8:58 PM

I am a little late to this discussion, but after reading all the posts I am surprised that nobody has mentioned a way to identify shorts as soon as a wire is attached to the wrong bus. You need a 9 volt battery, a simple buzzer and two leads with alligator clips. Wire the buzzer in series i.e.: lead - buzzer - battery - lead. Then attach the two clips, one to each rail. Then go about connecting your feeders. If you connect a feeder to the wrong bus the buzzer will sound immediately because you will have closed the buzzer circuit.

Just remember to keep the buzzer attached whenever anyone is installing feeders. We had a couple of incidents where someone disconnected the buzzer without telling the feeder installation crews. I won't go into the reason why they removed the buzzer because it would take too long to explain, but my point is that the feeder short circuit detection is useless if it was off when you installed a whole bunch of feeders and got one wrong. When you turn the detector back on it will buzz but you won't know where the short is. You will have to disconnect each of the feeders one by one until the buzzer goes off. Bang Head

Dave

 

I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!

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Posted by BigDaddy on Wednesday, July 25, 2018 8:50 PM

richhotrain
It should be simple enough to follow a colored wire protocol.

Stuff happens when you go from looking at the top of the layout and then work underneath and and look up. 

Henry

COB Potomac & Northern

Shenandoah Valley

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Posted by kasskaboose on Wednesday, July 25, 2018 8:41 PM

Correct about overthinking the issue.  The problem is I go on autopilot for wiring and that is a problem since I have a wire misplaced.  Much appreciate the help!

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Posted by richhotrain on Wednesday, July 25, 2018 7:23 PM

floridaflyer

Sounds like he had wires crossed and is overthinking the wiring of an atlas turnout. 

So it seems.

It should be simple enough to follow a colored wire protocol. For example, a bus can consist of red and black wires, and the feeders can also be red and black. Red to red, and black to black. But, you can still create a short if you wire a feeder to the wrong rail, and that seems to be what has happened here.

Rich

Alton Junction

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Posted by floridaflyer on Wednesday, July 25, 2018 7:17 PM

Sounds like he had wires crossed and is overthinking the wiring of an atlas turnout.

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Posted by richhotrain on Wednesday, July 25, 2018 7:10 PM

kasskaboose

All good for joining us on that posting.  I felt the need for starting another thread since on a slightly different topic that can help those wondering how to wire Atlas turnouts. 

If these are Atlas Custom Line turnouts, they are non-power routing with dead metal frogs. They are considered DCC Friendly. As such, there are no special wiring requirements. For maximum connectivity, they should be wired on all three ends.

Rich

Alton Junction

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Posted by kasskaboose on Wednesday, July 25, 2018 7:04 PM

All good for joining us on that posting.  I felt the need for starting another thread since on a slightly different topic that can help those wondering how to wire Atlas turnouts.

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Posted by richhotrain on Wednesday, July 25, 2018 6:38 PM

BigDaddy

Rich

We've branched out to another thread, to revisit plastic rail joiners.

http://cs.trains.com/mrr/f/744/t/271191.aspx 

Oh!   Confused   Confused

Rich

Alton Junction

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Posted by BigDaddy on Wednesday, July 25, 2018 6:00 PM

Rich

We've branched out to another thread, to revisit plastic rail joiners.

http://cs.trains.com/mrr/f/744/t/271191.aspx

 

Henry

COB Potomac & Northern

Shenandoah Valley

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Posted by richhotrain on Wednesday, July 25, 2018 5:06 PM

kasskaboose

Rest assured that I'm almost done with the issue.

Lee, what we are hoping for is some sort of progress report so we can offer some advice in helping to find the short. If you could give us some indication of how you are attacking the problem, that would be informative and helpful to us.

Rich

Alton Junction

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Posted by kasskaboose on Wednesday, July 25, 2018 4:30 PM

Rich,

Yes, you're correct that I have other priorities as do others.  Rest assured that I'm almost done with the issue.

Thanks for your (and others' help)

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Posted by richhotrain on Tuesday, July 24, 2018 12:01 PM

I think that this is going to be a long running thread. I mean no offense to the OP. I am sure that he has other priorities in his life besides tracking down a short. But, sometimes, you just need to start all over with the wiring if you are otherwise not sure how to attack the problem. So far, I don't see any progress in looking for a solution.

Rich

Alton Junction

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Posted by BigDaddy on Tuesday, July 24, 2018 11:50 AM

Floridaflyer, I think the OP is building a new layout.

Henry

COB Potomac & Northern

Shenandoah Valley

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Posted by floridaflyer on Tuesday, July 24, 2018 11:39 AM

You mention doing some wiring, was everythink OK before you wired the turnout in question?. If so the problem is at the turnout, if not then the problem lies elsewhere. As mentioned, the turnout is not power routing thus insulators are not necessary. If the problem is at the turnout, do as others have suggested and disconect the feeders either at the track or at the buss. If the short goes away, rewire the turnout using the red and blue diagram Rich posted. check for shorts after attaching each wire. 

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Posted by gregc on Monday, July 23, 2018 9:09 AM

if this is still a problem, why not

  • disconnect the feeders one-by-one until the short goes away, and if there is still a short,
  • disconnect the rail joiners one-by-one.

checking the polarity of the feeder and track or rail-to-rail connection clearing the short should confirm the cause and people can diagnose further.

there could be a short elsewhere

greg - Philadelphia & Reading / Reading

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Posted by rrinker on Sunday, July 22, 2018 10:40 AM

 The only time you need insulated joiners with Atlas turnouts is if yoou form a reverse loop or wye, where the train or loco can run through the turnout and come back facing the opposite way. Or if you deliberately want to power the siding indepdnently via an electrical switch so you cna cut all power - common to do for staging yards with DCC so that if someone fat fingers a loco address they don't end up running some other train off the edge fo the layout or smash it against track bumpers. 

 Unless you are using leftover Atlas track from the 50's, the early Custom Line were of the power routing type and needed insulated joiners or gaps like Peco Electrofrogs and Fast Tracks style turnouts. Anything new, though, or even in the past 20-30 years, no, no insulated joiners needed.

                                          --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 BigDaddy on Saturday, July 21, 2018 5:51 PM

kasskaboose
Someone at a hobby store told me to consider putting in an isolating joiner (plastic) since the turnout in question leads to a yard.

Your Atlas turnouts are not power routing so I am having a hard time visualizing a yard where this would be necessary.

Henry

COB Potomac & Northern

Shenandoah Valley

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Posted by richhotrain on Saturday, July 21, 2018 4:58 PM

Still sounds like you have crossed some feeders. The question is, where?

Or, you have a reversing section somewhere on the layout.

Rich

Alton Junction

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Posted by kasskaboose on Saturday, July 21, 2018 4:20 PM

Rich: I still have the short.  Sorry for not checking here sooner.  Someone at a hobby store told me to consider putting in an isolating joiner (plastic) since the turnout in question leads to a yard.  It can't hurt to try. 

The guy said for turnouts leading to sidings, crossings, etc. they all can be connected with metal joiners.

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Posted by rrinker on Tuesday, July 17, 2018 7:13 PM

 Like the crossing being two pieces of straight track laid across one another, you can think of the Atlas turnout as two pieces of straight track with one coming off the other at a slight angle. Or a single piece of straight track that to pivot slightly at one end - that might be an even better analogy. That may help visualize which rail should be connected to which side of the bus.

                                      --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 BigDaddy on Tuesday, July 17, 2018 7:03 PM

At 14:30 Ron demonstrates soldering a feeder into a bus.  He calls it a sub bus, but for your purposes, it is the same thing.

Henry

COB Potomac & Northern

Shenandoah Valley

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Posted by richhotrain on Tuesday, July 17, 2018 5:26 PM

Did you find and eliminate the short?

Rich

Alton Junction

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Posted by kasskaboose on Tuesday, July 17, 2018 5:15 PM

Thanks all for the help and the visuals.  What great founations of knoweldge we have!

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