Finding a short

You have to break the loop down into sections and start isolating track sections to find it. Start with large sections and break down the faulty section into smaller sections or take out one section of track at a time until the faulty section is found. If you are using track with plastic or wood ties, it should be easy to find, probably a switch.

Thanks Mike!  I was afraid that was going to be the case. I will proceed in the morning.

Follow-up for you.

I assumed in my response that you already disconnected the transformer and made sure it wasn't the problem and that you checked the track with the transformer disconnected from the track. Have you done that?

Hummm, no I did not disconnect the transformer. I’ll do that right now. Ok with the wires to that loop disconnected the transformer powers up as usual, no red light. I have continuity between the two track wires using my meter.

You can probably hunt it down by putting a much lower voltage on the track to generate a couple of amps of current.  Now you go around with a decent AC voltmeter and look for the place across the track that has the lowest voltage, that's near the short.

FWIW, I do this with DC as it's a bit easier to zero in with less variability than with an AC source.  I have a current limited DC power supply, I just set it to a couple of amps constant current and feed the track power and then I go hunting.  I've tracked down shorts on a loop a couple hundred feet long that way pretty quickly.

If everything was running fine and the short just came out of the blue, I'd start by a close physical inspection with a bright light, maybe a screw dropped off something and is the cause of the short.

I’m thinking the same as you John. I’m thinking something fell off of the train and caused the short. Ha! Might have known the suspected area is on the far side of the layout, very hard to get to. Heck, it’s been running great with no problems.

@Mr Union Pacific posted:

I’m thinking the same as you John. I’m thinking something fell off of the train and caused the short. Ha! Might have known the suspected area is on the far side of the layout, very hard to get to. Heck, it’s been running great with no problems.

You violated one of the safety rules of layout construction, don't make hard to access areas!   You know that's where all the problems will occur!

I wish I had a dollar for every time I've found a screw in the track, causing a short! IMHO

Alan

A few years ago I re-wired my whole layout because of a short. It turned out that the cause of the short was a wire that slipped out of a clip on a lock-on. LOL.

The re-wiring, however, was worthwhile because excess wire was removed, the wiring was simplified and organized better, and the trains run much better.  It was a good project to do during Covid. Arnold

Finding a short:

Earnest P. Worrel had a method, but I do not recommend it:

Andre

I have occasionally found it helpful to remove all engines and cars from the track, turn the voltage up to just before it triggers the transformer to shut down, and then walk around the track listening for a slight vibration and feeling for heat. Sometimes you can actually smell where the vibration is. Good luck.

Ed

Ok everyone, after an exhausting five hours of work this morning I think I have found the culprit. I checked the entire loop, red light still comes on. I disconnected every wire feeding the loop…red light still comes on. So I have a red and black wire from the transformer going into TIU fixed voltage line 2. I disconnected those two wires… no red light. I reconnected the two wires back to the TIU fixed voltage line 2 and I have no wire to the track. The red light on the transformer comes on. So, I’m guessing it’s the TIU?????

Shorted TVS diode in the TIU, easy fix.  I thought you disconnected everything from the layout, if I knew there was a TIU in the picture I'd have suggested that first.

Lol no problem. Can I just run the wires for that loop through the variable connection?

I have used the @ekaz method: heat and smell. Doesn't take much to generate enough heat to find a differential from the norm....

@Mr Union Pacific posted:

Lol no problem. Can I just run the wires for that loop through the variable connection?

Yes, variable channels be set as fixed channels.

it sounds like you are already set this way but the TIU need power for itself. It's an electronic device. It can get that by borrowing power from fixed1 input or aux power in.

@endless tracks posted:

I have used the @ekaz method: heat and smell. Doesn't take much to generate enough heat to find a differential from the norm....

In all honestly, yes, using my thermal image camera or just going around and checking for what is getting hot has been a real method used to find that short.

Yep, I know that power to operate the TIU comes through fixed input 1 and the fixed output 1 goes to my outside loop. Apparently fixed input 2 is shorted out. So can I just run my inside loop on variable input 2 set the transformer to 18 volts and run as usual?  

@Mr Union Pacific posted:

Yep, I know that power to operate the TIU comes through fixed input 1 and the fixed output 1 goes to my outside loop. Apparently fixed input 2 is shorted out. So can I just run my inside loop on variable input 2 set the transformer to 18 volts and run as usual?  

If you go into TIU settings for that variable channel and set it to fixed.

https://ogrforum.com/...ou-do-it-with-remote

Hey Vernon, I know I can do that with the DCS handheld, can I do it through the WIU on my iPad?