My meter doesn't have sound, but if I get close to the short, would I get a significantly different reading on the meter when checking? I suspect some problem with two drop feeders. I could find it with a little wiggle test as I work my way along under the layout but would like to find a way to get closer, faster.
Or is there any other kind of electronic diagnostic tool that I could buy and use to get close.
Thanks.
A meter, on the ohms (resistance) function will show you a short as zero or a very low ohms value. You probably won't be able to see any difference in reading as you get closer to the short. The best way to find them is isolate it as much as possible with switches, then either start disconnecting wires or a good visual inspection.
An important question; is this new wiring or existing wiring that went bad? If new wiring, make sure you didn't cross one of your drops to the wrong feeder, and make sure all joints are insulated.
In addition to the above, particularly section isolation. A good aid in finding a short is a helper. Someone to wiggle the wires while you check with a meter.
If the layout has been around a while and working, usually shorts are turnout or track related. Often overlooked are derailed cars/locos or something that has fallen across the tracks. If the track is completely clear, then check the turnouts
Counting on ohm values to get closer or further away from a short wouldn't really work, particularly if you didn't know what type of short you may have.
Richard
Make a cheap buzzer circuit, buzzer, 9V battery clip and a pair of alligator clips, all can be had from Radio Shack. Clip between the rails and it buzzes while the short is still in-tact. You can then work beneath the layout to break connections until you localize. This is much quicker if the layout is broken down into isolated sections.
Simon Modelling CB&Q and Wabash See my slowly evolving layout on my picturetrail site http://www.picturetrail.com/simontrains and our videos at http://www.youtube.com/user/MrCrispybake?feature=mhum
Thanks, all.
I have never had a problem with a turnout causing a short (only with drop feeders that have been stripped carelessly). In what way can the turnout develop a problem?
Yes, I use a buzzer when I am laying track and wiring. It is essential.
Luckily, the last section of the layout completed can easily be isolated by disconnecting the bus wire from a terminal block. On then next layout I will design in more blocks. So it is an old section with the problem.
No locos or obstacles on the top of the track, darn. But I am going to vacuum carefully today too.
If you had a buzzer on the track during the wiring, then it ought not be a misswired feeder. Did this short develop after the work was completed?
Step one...Suspect and undo the last thing you did.
I assume that you have a reason for suspecting the two feeders. Disconnect them.
Look for a tool or whatever laying on the track. If you were running trains when it occurred, check the train that was moving.
The buzzer does not check anything the meter won't.
If the layout is divided into segments, turn them all off. Then turn them on one at a time.
Dave
Lackawanna Route of the Phoebe Snow
Finding a short that has occurred on an old section of layout can be difficult and is one of the hardest things in electrical work to do. As was mentioned before, check the last things that you were working on before the short occurred. Also, a power supply or DCC system could have gone bad and is causing the problem. I would proceed in the following order:
Check where you were working last.
Disconnect the power pack or DCC system from ALL layout track and test it with a short section of track and a locomotive to make sure the main power component is good.
Remove ALL cars and locos from ALL layout track.
Run a vacuum over all track to pick up loose spikes, nails, and rail joiners.
Isolate the two sections of the layout and check each individually.
Once you have found the bad major section of layout, you will have to further isolate the layout. I suggest dividing the bad section in half. Then divide that bad section in half again. Soon you should get down to an area that you can really inspect closely. The division needs to be track as well as wiring providing power to each section.
While you are dividing things down, throw each turnout in the shorted section. First one way, then the other while checking the meter or buzzer.
Elmer.
The above is my opinion, from an active and experienced Model Railroader in N scale and HO since 1961.
(Modeling Freelance, Eastern US, HO scale, in 1962, with NCE DCC for locomotive control and a stand alone LocoNet for block detection and signals.) http://waynes-trains.com/ at home, and N scale at the Club.
That is exactly how I am progressing.....clear the tracks, unplug the throttles, clean the tracks, check last first and start dividing. So far the most annoying of situations has arisen......a doubled up problem. I found I have a short in the latest section of layout (that was one I could easily isolate) and in the old section. Nuts! After no problems for year and years. At least I caught that early.
If I don't find anything obvious in the next few days I am going to begin sectioning with a Dremel and pulling the buys wires from sector terminal blocks. That will bet me closer and closer.
I will prevail!
One other thing to check; If you have cut your gaps with a Dremel and cut off disk and DIDN'T put an insulator between the two sections of rail (small piece of plastic or epoxy), it is possible that they closed up (touching again) and are causing the short. I would go around and examine each gap that you should have very closely and make sure they didn't close up due to either the temperature or sliding rail.