Auto reverse module

[McCullough]

I have installed a DCC Specialties reverse module PSX-AR on a reverse loop. I have gaped the rails beyond an Atlas code 100 Y switch. I have wired the module according to the instructions for a basic reverse loop. I am having trouble running the gap on the side of the reverse loop where the transfer of polarity occurs from rail A and B. I can run the gap at high speed and the reversal of polarity in the engine occurs but can not cross the gap at slow speed, the engine shorts out. I can push over the gap and the engine continues on it's way. Can anyone suggest something that may help me out with this problem?

[Jim Banner]

If I read your posting correctly, you have two pairs of gaps, one pair for each leg of a Y turnout, for a return loop.  But you get a short circuit at only one pair of gaps.  This sounds like the reverser is not throwing properly.  That is, it is not throwing at all.  In normal operation, it should throw for both pairs of gaps, assuming you always go around the loop the same way.

I am not familiar with that particular reverser and you did not mention what command station/booster you are using, so I cannot tell you whether the reverser is rated for a higher current than the command station/booster can produce or whether your wiring is inadequate for the job.  Reversers work by detecting a short circuit, that is, a current draw above some limit.  If the command station/booster cannot produce that amount of current, the reverser will not see a short circuit and will not throw.  If the wiring to the main line or the wiring to the reverser, or the wiring from the reverser to the loop or the wiring within the turnout are inadequate, then the reverser will not see a short circuit.  Some reversers are adjustable to compensate for this problem.

Jim

[full maxx]

If I read your posting correctly, you have two pairs of gaps, one pair for each leg of a Y turnout, for a return loop.  But you get a short circuit at only one pair of gaps.  This sounds like the reverser is not throwing properly.  That is, it is not throwing at all.  In normal operation, it should throw for both pairs of gaps, assuming you always go around the loop the same way.

I am not familiar with that particular reverser and you did not mention what command station/booster you are using, so I cannot tell you whether the reverser is rated for a higher current than the command station/booster can produce or whether your wiring is inadequate for the job.  Reversers work by detecting a short circuit, that is, a current draw above some limit.  If the command station/booster cannot produce that amount of current, the reverser will not see a short circuit and will not throw.  If the wiring to the main line or the wiring to the reverser, or the wiring from the reverser to the loop or the wiring within the turnout are inadequate, then the reverser will not see a short circuit.  Some reversers are adjustable to compensate for this problem.

Jim

wow, you said a mouth full

[McCullough]

Thanks Jim for your input, I appreciate your advise. I've taken a second stab at it, checked for short or wrong wiring and still am at a loss. I am powering things with NCE Power Cab. I'm wondering if I need a separate booster. Also am wondering why when I push over the gap thatt the engine continues on it's way. This indicates to me that a transfer of polarity is happening. Am I correct in thinking this? Just don't know what to do. Thanks again Jim

[jward]

i believe the decoder itself controls the direction the locomotive moves.

consider for a minute a dc locomotive. if it is running in one direction and you pick it up and put it back on the track facing the opposite way, it will continue in the same direction as before. it will run in reverse.

a dcc locomotive on the other hand, will continue to run in the forward direction no matter which way you place it on the track. it doesn't matter which "polarity" is on the rails, the decoder controls the direction.

i believe this is why the locomotive continues in the same direction once it is over the gap.

[Tim]

McCullough

The power-Cab has a trip current of about 2.5A.
You need to set jumper J6 on the PSX-AR to pins 1-2.
It will cause the PSX to trip @ 1.27A. This is below the trip threshold of the
Power-Cab.

Also is it possible that the end of the train has not cleared the first set of gaps?

Tim Anders
Souderton, PA

[McCullough]

Thanks Tim, I'm thinking that I am in too deep. How do you change the J6 jumper if this is required?? H

[Tim]

McCullough

On page four of the PSX-AR manual, at the top left side of the page
is a chart showing all the possible connections to J6.

For 1.27A connect pins one and two of J6.

If you have screw terminals put a short wire between 1 and 2.
If you just have solder pads solder a wire between 1 and 2.

The holes/terminals are numbered L to R .

At the top of page three is a photo of the board showing all the jumper locations.

You do have to add the jumper because the default trip current of the PSX-AR is 3.31A.
This is higher than the trip current of  the Power-Cab.

Tim Anders
Souderton, PA

[McCullough]

Tim, I followed your last instructions re a jumper wire at J6, pts1&2. I'm still shorting out. So here I go again: I have a Y switch, atlas code 100 into the reverse loop. I have gaped beyond the switch on each track leading from the Y. I have connected my input pts before the Y and the output pts beyond the gap on the return side of the loop. I have connected my buss line for the district (maybe this is creating the problem???) to my input wires thinking this would power things up replacing a booster. Is a booster my only alternative? Probably shouldn"t put this module in the hands of a novice. Hugh

[Jim Banner]

Hugh,
Are you sure things are shorting out?  If you connect a small 12 volt bulb across the rails somewhere away from your reverse loop, does it go off or at least go dim when the locomotive stalls?   Reason I ask is that an open circuit can also make a locomotive stall.  If it stalls between the frog of your Y turnout and the gaps but the test light stays bright,  I would suspect bad wiring inside the turnout.  It appears that Atlas has quit soldering/spot welding jumpers in their turnouts in favour of relying on the plastic parts to keep the metal parts touching.  I have had Atlas turnouts fail to power one or the other route because of this.  But the solution is simple.  Add your own external jumpers to the turnout - left rail to left rail and right rail to right rail beyond the frog.

If the test light goes dim or out during the above test, then you are getting a true short circuit.  And if it happens only while the pickup wheels are over the gap, then I would start thinking in terms of a faulty reverser.  The jumper Tim suggested should have taken care of one of the problems I mentioned before - reverser short circuit current exceeding current available from the command station's built in booster.  It sounds like your wiring should be adequate but to make sure, put a quarter across the rails at the input of the wye and confirm that the command station kicks out (I assume it has some sort of short circuit indicator.)  Incidentally, putting the quarter on the tracks beyond the turnout but before the gaps, then confirming that each route causes the command station to kick out (shut down,) is another way to confirm adequate wiring through the turnout.

A frustrating problem, no doubt about that.  But we will do all we can to walk you through it.

Jim

[McCullough]

Tim/Jim I so appreciate your help in trying to solve my problem. So I tried the quarter trick before the Y and after the Y, each time the system shorted out. I tried the 12 volt light and it shut off as soon as the first set of trucks hit the gap.  Next? Thank you again. H.

[Jim Banner]

At this point, I believe you have a bad reversing unit.  Hopefully it is still under warranty and you can exchange it for a new one.

Jim

[Chris350]

Here's one more thought.  I wired my PSX-AR's to the bus at one terminal block, and the other goes to the loop.  I have no jumpers from outside the loop across the gaps.  The loop is powered solely by the PSX-AR.  I have had very good luck with them, far better than the Digitrax unit, which I let the "magic smoke" out of.  I have a loop and a wye, and one reverser per circiut.  I'll have to look into the trip current settings as well.  More learning.  I use a Digtrax Zephry.

[McCullough]

Chris, I'm a bit thick when it comes to this stuff. Can you explain step by step hook up for your PSX-AR. bus to terminal??? Are you using a separate booster for power??

[McCullough]

Tim/Jim - What do you think about what Chris said above? H.