Tortoise switch machines don't work

[dadret]

I have 17 Tortoise switch machines on my new DCC layout and I hooked them up per the "Bi-Polar DC with SPDT switches" instructions supplied with the Tortoise using two Circuitron 12V DC power supplies and Mintronics SPDT (with centeroff) switches.  Everything worked fine initially but now only one side of ALL 17 machine works.  When I flip the switch one way the machine works but when I go to the other side there's nothing - the switch does not cycle and there is no sound indicating that its trying to.  This happened after I soldered the leads from the Tortoise to the bus wire (the feeds to the switches are connected with wire nuts).  Since its all of them not working I would suspect the power supply itself or a break in the wire near the pwoer source but I can't find any obvious problem.  If one of the power supplies went bad I would think neither side would work.  Anybody got any ideas where to start looking before I spend the rest of the day under my layout. 

[baron9]

I also use tortorise switch machines and I was told that a 12volt power supply would be enough to handle 22 switch machines. The only difference is that I use DPDT toggle switches,maybe that is why they only work in one direction. Sometimes I have a problem with wires touching other connections and a simple movement of a wire or two works for me.

[cacole]

Your SPDT toggle switches are not reversing the polarity to the Tortoise to make it go in the reverse direction.  You need to use DPDT toggle switches wired into a X on the end terminals, with both power supply leads connected to the switch, and the machines connected to the center terminals so the polarity is reversed.

[dadret]

If using the SPDT switches insteead of DPDT switches is the problem then why did they all work at one time.  They all worked until I finalized all the connections.  I have now found that one of the two power supplies was not working (no DC output) so I replaced it but I still have the turnouts only working in one direction.  I disconnected the last few switch machines I hooked up  to see if I did something wrong there but that didn't make any difference.  I'm very confused now expecially since the Tortoise instructions clearly show SPDT switches.

[cacole]

Do you have your two separate power supplies connected to the SPDT toggle switches as shown in the second diagram; i.e., plus output to one side of the switch, minus output to the other, and the two power supplies connected together as the common side?  If not, you're not properly reversing polarity to the Tortoise.

That's why I prefer the simpler wiring of the first diagram using a single power supply and DPDT toggle switches.

 

[oleirish]

I have ten of them on my layout and never had an glitch in them  HUMMMM! I use DPDT center of switches W/Leds showing direction(RED&GREEN)I'am only useing one power supply(12VDC)That I got from RS for about$6.00.I've set them up with an X on the switch for reverseing,

JIM

[selector]

Have you checked the switch for power output on the posts that could be affected?  It sounds to me like a defective switch.

[dadret]

I have all the components connected just as the second diagram shows.  What still confuses me is that ALL of the tortoises worked like they're supposed to at one time and now they don't.  One possibility is that not all of the wires from the circuit board on the tortoise (numbered 1-8) are connected the same to the switch and bus wire.  I tired to make sure that the wire from position 1 on the tortoise went to the center lug on the switch and from positon 8 to the bus wire but I may have mixed these.  Would that make a major difference?

[cacole]

If each Tortoise is wired to a separate SPDT toggle switch, it should make no difference except to reverse the direction that the Tortoise moves, because that would just reverse the polarity.

Are you sure both power supplies are functioning, and that you have the positive output of one and the negative output of the other connected together as the bus wire?  If you connected both power supply positive terminals together, or both negative terminals together, you have no polarity reversal through the toggle switches.

 

[Texas Zepher]

Your SPDT toggle switches are not reversing the polarity to the Tortoise to make it go in the reverse direction.  You need to use DPDT toggle switches wired into a X on the end terminals,... .

No, he doesn't.  He specifically stated he was using the "Bi-Polar DC".  Please read and understand the question before telling someone they have to totally rewire their layout to the way you did it.

I hooked them up per the "Bi-Polar DC with SPDT switches" instructions supplied with the Tortoise using two Circuitron 12V DC power supplies and Mintronics SPDT (with centeroff) switches.  ... If one of the power supplies went bad I would think neither side would work.

No, throwing only one direction is exactly what would happen if one of the power supplies went bad.  One power supply is for each direction.

Have you checked the switch for power output on the posts that could be affected?  It sounds to me like a defective switch.

Have you tested both power supplies at their outputs to see if they are both producing power?

[dadret]

Both power supplies are working.  I'm using Miniatronics WT412 Filtered 12V DC, 400mA power supplies.  My tester shows that they are both putting out 14.4V however - Is this maybe the problem?  I've checked, disconnected, reconnected, etc and the positive output of one power supply is definitely connected to the negative of the other and the bus wire connected to these.  The other positive output is connected to one side of the switch and the negative to the other side and this worked well at one time but now it does not.  I think I'm through messing with it for today as its too frustrating.  I'm just about to go get a bunch of DPDT switches.

If the toggle switch is defective, then they are all defective and thats not too likely.

[Anonymous]

Sounds to me like you my have crossed a wire. I would check this carfully. When you throw the toggle one way they work fine. Now, did you try each toggle?

[Vail and Southwestern RR]

If it worked, and now it doesn't, whatever you did in between was the cause.  That's kind of an obvious statement, bu I don't know how many times I've had to relearn it.  Sinc eyou;ve got the meter, check what voltages are at the switches when you throw them.  There's no rocket sciene here, more likely a loose or broken wire.  Just start at the supply and work your way to a Tortoise, checking the voltage at each step along the way.  Slow and deliberate will find it!

 

[dadret]

Thanks everybody for your help.  I'm not really sure what I did but they all seem to be working correctly now.  I think the problem may be that I used solid rather than stranded wire (I think its easier to solder) for the bus and switch wires and where I joined several wires together with wire nuts some of the solid wire broke.  All I really did (after screwing around with it all day) was  undo some of the wires that I had the wire nuts on and twist them together without the wire nuts and the switch machines started working - Fortunately this was on the first set of switches. Tomorrow I'm going to remove all the wire nuts and solder the wires together and then go back to stranded wire.

[Jacktal]

     just a guess here...you say that everything worked fine for a while,so my guess is that you have mixed two wires on one or more switch(es).Since you're using center off SPDT's,I'd try switching them all "off" and then try them one at a time.It's possible that they'll all work fine until you toggle the faulty one.You may have tried this,but if you haven't,that would be a good way to start.

    BTW,using solid or stranded wire has no effect on the electrical operation,so going back to stranded won't fix your problem.The error is in the schematic somewhere.

[Stevert]

Tomorrow I'm going to remove all the wire nuts and solder the wires together and then go back to stranded wire.

  Excellent decisions for this type of wiring!  A properly soldered joint will always be better than a wire nut from an electrical standpoint, and solid wire of the gauge you're probably using for your Tortoises is prone to breakage if it's flexed very much at all.

  I don't know how many times I've seen the conductors of solid bell or phone wire break inside the insulation, causing an open circuit. 

  Sorry you had to go through some grief to get to this point, but hopefully you've prevented someone who reads this thread from going through that same grief.

 

Steve