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I have many DZ-1000 switch machines on my layout. I have one that has started acting up after working well for a number of years. Intermittently, when thrown, it throws, but then bounces partially back to the other route, although the LEDs on switch machine and controller show the initial thrown route. It does this for both routes. Any ideas? This is independent of the non-derailing feature.  It happens when thrown from the controller on the panel.

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Thanks for your questions.

It stays there. It is not hard to change position manually.  I did it 20 times manually with no bounce back.  I then threw it with the controller until it bounced once (maybe 15 times before it bounced).  I then did it 20 times manually with no bounce back.

I did do some wiring at the same control panel not too long ago, which is hinged, so some wires moved during the raising and lowering process

To eliminate the DZ1000 or confirm it has a circuit issue is it possible to connect the wires from the control board for another DZ1000 you is working, to the problem machine?

If the machine starts working you know you have a wiring issue
If the machine acts the same (bounce back), you can be pretty sure you have a internal machine issue. This assumes you don't have non-derail feature on the turnout output tracks. I don't think isolated middle rail track on either side will be the cause of the issue.

By the way what voltage level are you applying to all the DZ-1000s?


Last edited by Joe Fauty

Great suggestion!

12v AC.

So I disconnected the three wires at the switch machine, and used jumpers to an adjacent machine. No bounce back, although, a few times, the jumped switch didn't throw at all--could be a jumper connection thing.  Seems the DZ-1000 is okay. Maybe the 2-button controller is the issue?

I do have both these switches wired for the non-derail feature, both have worked for several years. This testing has been with the 2-button controller, not cars on rails.

I may have a spare DZ 1002 controller to try next.

Ken - excellent! Please let me know if it turns out to be the controller.

12VAC is just fine.

I did not know you are running DZ-1002 controllers. While I have nothing against them I installed DPDT momentary toggle switches to run my switch machines. However even theses can go bad. I had one go bad after about 5 years. Fortunately when I designed my control board I put in more toggle switches than I needed which paid off since I only needed to move one wire instead of having to get underneath the control board and disconnect the toggle switch.

I have had a similar issue with my DZ-1000 switch machines. If I recall, the red LED would stay lit although there were no trains in the area. I contacted Z-Stuff and was told the issue resides in the diode (red LED). They sent new LEDs and this fixed the problem. However, when I had the same problem with a different switch machine, I simply removed the LED. An explanation was never provided, so hopefully your issue will shed some light (no pun intended).

I responded to Steve's suggestion by putting electrical tape under the the DZ-1002. This had no effect on the problem.

Here is Dennis Zander's feedback: "Try disconnecting the GREEN and YELLOW wires. It sounds like one of them is shorted to common."

So I disconnected both and the wires for the non-derailing feature. Not surprisingly, the switch did not throw under the train. Then I hooked up the yellow, but not the associated non-derailing wire. No problems, but I can only throw the switch one way. Then I hooked up the green, but not the associated non-derailing wire.  The switch did not throw under the train. I did not observe bounce back, but I didn't throw it that many times.

The problem seems to be the wires for the non-derailing feature. More to come...

Today, I first threw the switch about 3 dozen times: no bounce back. Next, I measured the continuity between the short frog rails used for the non-derailing feature and all the other outside rails in the vicinity: no short on either one. Next, I added the wire for the non-derailing feature to the green wire.  I ran a train through it 9 times. At no time did the switch throw under the train. Then I threw the switch about 40 times: no bounce back.

Tomorrow, we'll see what adding the non-derailing wire to the yellow does...

The wire for the non-derailing feature that connect to the yellow (diverging route) seems to be the problem.  Switch threw under the train with both non-derailing wires connected. When I threw the switch straight and backed the engine through from the frog end on the straight route, the switch threw curved, but the green LEDs remained lit on both switch machine and DZ1002. Removing the non-derailing wire for the diverging route/yellow made everything else work again.

Still scratching my head as to the mechanism of the problem.


I will add to Scott - make sure you are using the inside rail. Another way to check is too put your voltmeter into continuity, place one probe on a grounded rail and the other on the insulated rail and see if they are connected to each other.
Another thing I remember - if the machine ever flutters (point rails going back and forth) check the rail pins. This is particularly true for Ross turnouts. A pin on a ground rail will come get too close to a pin for a power rail.

Ken - nothing to do with you. This is about the 6th time I have relearned this lesson. If something goes wrong disconnect everything associated with it and start over again one wire at time.

Problem solved!

I had checked continuity with the multimeter before and found no issue. I did it again: still no issue. Joe's suggestion about rail pins got me to look up close and personal at the switch.  I didn't see any problem with rail pins, but there was debris between the ties, and nearby, I noticed a few very fine steel wires that had flown off a wire wheel.  After vacuuming the vicinity, everything ran with no problem. It seems a small piece of fine, bare steel wire would intermittently make contact, especially when wheels were rolling by.

Thanks to everyone for your help. Such a relief to get this working again.

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