track short circuit?

[jockellis]

G'day, Y'all,
When I laid the track for my switching layout, everything ran fine. But now that I've started putting down the Woodlands Scenic grass, etc, the train will only run in one direction. I'm using an elderly MRC twin power power pack, an Atlas 215 selector and an Atlas 220 controller. I've got a multi tester which I don't really know how to use. Anyone got some suggestions?
Jock Ellis
Cumming, GA US of A

[Anonymous]

When you say it'll only run in one direction, are you sying that it dies when you try to change directions? Or is it de-railing?

Electrically, if the train will run one direction, it'll go the other way if all things are equal. I'd be looking for a problem with the electric switch that chages direction on the power supply. Instead of flipping the switch, you can also swap the lead on the power supply. Don't change anything else when you do it. If the locomoive goes backwards, then look at whatever you do or did to make it not work.

You can use the multi-tester to watch the track voltage. You can also put it in series with the power supply to watch current, which I've found to be VERY helpful in watching for dirty track and such.

Mark in Utah

[SpaceMouse]

I think Mark is onthe right track. The first thing I would do is test the track with your multi-testor. Set it to measure DC volts and put one lead on each track. If it is analog you might have to switch the leads on the track to get a reading. Then flip your directional switch and do it again. It should read the same voltage only reversed. (-15.4v and 15.4v for example). If it doesn't it is probably the switch in the transformer.

[Anonymous]

Did you check all the switches, switch points for anything?

[mrgstrain]

I am not very good with electronics but it is not a short circuit, it is an open circuit which means that the power will not go from point A to point B because of a broken wire or a bad switch which means no connection. Now is the time to learn how to use your tester. Good luck.
Larry

[howmus]

Doesn't sound like a short cicuit. Much more likely you have an open circuit here. My guess is that the Atlas selector or controller is being used to reverse the DC to reverse the train. I used some of the Atlas controllers when I first started to build my layout over 20 years ago. Some didn't work out of the box and what I was told back then was that they wear out after a time and have a habit of picking up dirt so they don't make contact. If that is the scenario, then I recommend replacing the items with standard toggle switches.

[Anonymous]

I had a similar problem with my track after I sodred(?) it. I came to find out my track was dirty. I suggest checking your engine wheels, and track for dirt, then progress to the more advanced stuff. Always remember the KISS principle (keep it simple stu well you know the rest)!!

[Anonymous]

If dirty track were the problem it is not likely that the locomotive would move in one direction and not the other. The track is either too dirty to pass current onto the wheels or it's not, direction should not play a part. I agree with above posts that it does not sound like a short but more like an open in one of your Atlas devices. I have never used those on a layout so I don't know what their "bugs" tend to be, but you might try just running wires directly from the power pack to the rails--if the train moves, fine. Then put the wire that was to "this" rail onto "that" rail and vice versa without changing any switches on the power pack. If the train now moves the "other"way you have eliminated both the power pack and your locomotive from suspicion and can begin to chech out your Atlas controllers, etc.

Good Luck

[jockellis]

G'day, Y'all,
Thanks for the ideas. I know almost nothing about electricity so thanks for telling me it was an open circuit.
Before I wrote my post, I switched the direction switch on the power pack which would basically bypass the 215 controller switch but it didn't work. And the multimeter which I had attached to the power pack's variable DC terminals dropped from 9 volts and up to only 3.
Speaking of dirty track, after I spray painted my track I cleaned off what I thought was all the paint. Later, after successfully running the Atlas S-2 over one siding, I noticed that I had forgotten to get the paint off it. But it had not bothered the locomotive in the least! But that was before the scenicking with ballast and such.
No, I haven't checked the switch points but the problem occurs in all the electrical blocks. I'll go back tomorrow, Saturday, and see what that might do. What am I looking for? To see that the points touch the track on both sides?
Thanks again,
Jock Ellis
Cumming, GA US of A

[howmus]

QUOTE: Originally posted by jockellis

G'day, Y'all,
Thanks for the ideas. I know almost nothing about electricity so thanks for telling me it was an open circuit.
Before I wrote my post, I switched the direction switch on the power pack which would basically bypass the 215 controller switch but it didn't work. And the multimeter which I had attached to the power pack's variable DC terminals dropped from 9 volts and up to only 3.
Jock Ellis
Cumming, GA US of A

Is this a problem with one loco or several locos? I ask because what you are now saying describes a problem that is more likely to be something binding in the engine. The drop to 3 volts or less would indicate a short or a stalled motor. Try your track with a different loco.

[Anonymous]

QUOTE: Originally posted by jockellis

G'day, Y'all,
Thanks for the ideas. I know almost nothing about electricity so thanks for telling me it was an open circuit.
Before I wrote my post, I switched the direction switch on the power pack which would basically bypass the 215 controller switch but it didn't work. And the multimeter which I had attached to the power pack's variable DC terminals dropped from 9 volts and up to only 3.
Speaking of dirty track, after I spray painted my track I cleaned off what I thought was all the paint. Later, after successfully running the Atlas S-2 over one siding, I noticed that I had forgotten to get the paint off it. But it had not bothered the locomotive in the least! But that was before the scenicking with ballast and such.
No, I haven't checked the switch points but the problem occurs in all the electrical blocks. I'll go back tomorrow, Saturday, and see what that might do. What am I looking for? To see that the points touch the track on both sides?
Thanks again,
Jock Ellis
Cumming, GA US of A

When you switched polarity on the power pack and the voltage droped to 3 volts from 9 the only thing that changed in your circuit was inside the power pack. My guess is high resistance on one terminal on the polarity switch inside the power pack. Does the power pack geet very hot if you leave it in the position with the low voltage? Try another power pack if this is happening.

[howmus]

QUOTE: Originally posted by bukwrm

When you switched polarity on the power pack and the voltage droped to 3 volts from 9 the only thing that changed in your circuit was inside the power pack. My guess is high resistance on one terminal on the polarity switch inside the power pack. Does the power pack geet very hot if you leave it in the position with the low voltage? Try another power pack if this is happening.

Since the same thing is probably occurring when he switches polarity with the Atlas Controller, that would elliminate the power pack in my thoughts. Jockellis, take the loco off the tracks (all locos and other equipment that draws power to the track) and check the voltage to the tracks. Then switch polarity in the pack. If the voltage drops, it is the pack, if not, it is the loco. What I'm thinking is that the brushes in the motor may be binding. I have had that happen.

[rrinker]

Good call Howmus, my father in law had an Athearn BB that ran poorly, and was a LOT noisier than most. So I took it apart figuring it needed lubrication. Looking at the motor I saw one of the brushes somehow got turned 90 degrees so instead of the nice curved shape fitting agains the commutator, just the two edges were touching. Pulled the clip off, turned the brush around the way it is supposed to be, and all was better.

-_Randy

[Anonymous]

QUOTE: Originally posted by howmus

QUOTE: Originally posted by bukwrm

When you switched polarity on the power pack and the voltage droped to 3 volts from 9 the only thing that changed in your circuit was inside the power pack. My guess is high resistance on one terminal on the polarity switch inside the power pack. Does the power pack geet very hot if you leave it in the position with the low voltage? Try another power pack if this is happening.

Since the same thing is probably occurring when he switches polarity with the Atlas Controller, that would elliminate the power pack in my thoughts. Jockellis, take the loco off the tracks (all locos and other equipment that draws power to the track) and check the voltage to the tracks. Then switch polarity in the pack. If the voltage drops, it is the pack, if not, it is the loco. What I'm thinking is that the brushes in the motor may be binding. I have had that happen.

You are right, I was thinking of my set up, currently the power pack is the only control I have. If you set everything so you get good voltage at the track. Switch polarity at the Atlas Controler, go bak to the original settings then switch polarity at the switch on the power pack. If the voltage drops both ways then the problem is somewhere else but if it drops with only one switch than you have found the problem.

I had not even thought about the brushes flipping when the motor reverses. Good thought. I think I have spent to many years installing parts.

[jockellis]

G'day, Y'all,
I got out a newer MRC powerpack and held the leads to the end of a track. Everything worked perfectly. Note to self: replace 1960s era Golden series two cab powerpack with new one because that newer powerpack was so much better than the 1964 model. But back to the old powerpack, the problem persists. It is both cabs leading me to believe it has to be in the common wire.
Jock Ellis
Cumming, US of A

[jockellis]

G'day, Y'all,
I just thought of another question. When I touch the leads to my voltmeter to the track, the needle jumps to 16 volts as soon as I crack open the throttle. Do DC powerpacks use constant voltage and variable amperage like the Magnaflux magnetic particle inspection NDT machine I run at work?
Jock Ellis
Cumming, GA US of A

[rrinker]

No, but an old rheostat power pack is not in any way regulated, and the loa dand rheostat must be matched. So your no-load voltage reading even witht he throttle barely cracked is going to be high.
For this reason, the old pack will have poor control of a newer quality loco like Kato or Stewart. And an HO pack won't control N scale locos very well - I'm talking rheostat packs here, a transistor pack won't have these problems.

--Randy

[jockellis]

G'day, Y'all,
Thanks, Randy. I don't know nuttin' about 'lectricity.
With regard to the other problem, it started working again, all by itself. I never had this problem on another layout with another 215 switch. If it continues, I will replace it. Anyway, I've enjoyed hearing from ou all. thanks.
Jock Ellis
Cumming, GA US of A