A Short ?


C

csxfan

Member
Now with my DCC all locos just run only in one direction. Is it because there is a short somewhere since I have a lot of crossings and therefore loops and I suppose I misconnected the loops ? Can I measure or discover the short with a voltemeter ? Or how can I find out for sure if there is a wrong polarity or something ? Please help. I tried it with MRC 260 and have had the electrical issues and have not worked them out yet. I am sure there is a number of shorts, wrong rails.
 
Assuming your system IS DCC, and that it doesn't shut itself down due to a hidden short, then any problems you have are in the decoder...most probably. I doubt the base command station or throttle is the problem with scrambled bits somewhere. If the system powers up, and doesn't immediately shut itself down, then your wires are fine. If you have isolating gaps, really in AC the polarity doesn't matter providing you don't have a conflict with one side or the other coming into contact with 'itself' either via wire or rail and connectors.

Therefore, you have altered the decoder(s) somehow to all move in the same direction and not be able to reverse. I don't know what could cause that, and will let experts on inadvertent MUing or specific CV changes help you there. Mostly I wanted you to know that, since DCC is AC current, the direction of movement imparted to the drive mechanisms is dependent on the decoder...only. It is different in DC where polarity does matter. It cause the rotor to actually reverse its direction of rotation.
 
He may have some reversing loops that short when he runs into them in one direction and not the other, depending on how the switches are thrown.

csxfan: post your track plan so that people can help you
 
no reversing loops, that I know of, at least, sir, and I do not have a track plan yet though I assembled it, over 300 feet, lol, I will have to get down to do it, the way I see it, because the messy layout just doesnt work.
 
More than likely, a CV is messed up. This could be done with a bad command inadvertently, a short, with all locos on the track.

A decoder reset, or a reading of the CV's by a friend who has JMRI could determine this.
 
csxfan said:
Now with my DCC all locos just run only in one direction...
Click to expand...

We need a little more information to help determine what the problem is. When you say "one direction", is that one logical direction(will only run forward or only run in reverse) or is that one physical direction(will only run left to right or only run right to left regardless of which way the locos are facing)? Do you have any control at all over the locos(can you control the speed or do they simply take off at full speed)? Does the direction the loco is facing on the track have any effect on the symptoms?

If the locos will only travel in one physical direction then it sounds like you might have blown half of the booster circuit in your DCC system or, if possible with your system, wired it so that half the booster circuit is shorted or is not connected to the track.
 
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