Non Derail trouble dz2500

Make sure you have the white stripe facing in correct position as stated.

Nothing wrong with the diodes you're using, so Rod's point is the only thing I see that might be an issue.

I do hasten to point out that the Lionel 1908010 CSM2 DZ-2500 Breakout board from Lionel that is used with the DZ-2500 has a different diode scheme for protection of the non-derailing inputs.  It has 100 ohm resistors in series with the leads to the DZ-2500 from the non-derailing rails.  On the DZ-2500 side of the resistor, there's a diode to common with the cathode (band) toward the resistor connected to the DZ-2500 input wires.  The anodes of both diodes go to power common.  I wonder if this was in response to some input that the diode didn't always work or just a different protection scheme?

Not too well versed in electrical, what john said went over my head a little bit there. I'm not using any breakout board and I do have the stripe toward the isolated rail . The diodes came in a hundred packs so I've used four of them they all act the same way . Is anybody else actually using these diodes and having it work fine? Or they just wiring from the rails directly to the switch and not really having any problems?

I have an interesting update that maybe somebody can make heads or tails of. I noticed that when the diodes ARE installed that trying different Rolling Stock sometimes I get some that act a little tiny bit better than others with their reliability to throw the switch once they roll onto the isolated rail. I started doing a audible continuity check on Wheels of these. Checked about four different cars and the wheels do not check out well , very intermittent and choppy. I have cleaned  the rail and these wheels with electrical contact cleaner and it is still the same. The cars that give me the most intermittent continuity on the multimeter are the ones that fail to throw the switch most of the time.

  If I was just to stop here I would totally assume that this is just the fault of the Rolling Stock Wheels because it all seems to make sense. However every one of these same cars if I roll them onto the switch isolated section and I do NOT have the diodes in line oh, then they all work 100% of the time. So it stands to reason then that there's something about this whereas the diode is not allowing a choppy intermittent continuity connection to send the proper voltage through itself to let the switch trigger.  Is there anyone that can help with this? Is is there a different rating of diode that might allow this to work?

Perhaps an email to Dennis at Z-Stuff, he's the expert here.

I cannot find where the diodes are used for the DZ-2500.  There are instructions for diode use with the DZ-1000, but not the DZ-2500.  Where can I find the data on using the diode with the DZ-2500?  Thank you.

Right in this thread Ron!  However, as I have noted above, the CSM2 breakout board handles the diodes a different way.

John,

Thank you!  Should have read that better.  After first paragraph I thought - I have not seen that.  I went through my Z-stuff folders, their web site and Ross' web site and nothing on this.  It is now in my DZ folder and I will check it out to see if I have the same issue as JohnnyB.  However, I am going with the breakout boards now.

I would have thought a low value resistor and a TVS to ground that limited the voltage spike to maybe 10-12 volts would have been most effective.  I'm presuming that the worry was about a negative excursion of the voltage on the non-derailing pins, so the diode would prevent that.  If that's the case, then the TVS wouldn't be as effective, maybe 12V is too much negative bias on the pin.

I suspect only Dennis at Z-Stuff really knows what he was protecting against with that fix.

Am I to understand that using a Lionel breakout board would prevent whatever reverse voltage Dennis was warning about?

Well, that's what the documentation for the CSM2 Breakout board alludes to, and there are diodes and limiting resistors on the board.  As I noted before, they aren't in series with the non-derailing lines, but rather returned directly to ground.  Since I believe this was originally designed by Jon Z. at ERR, I'm guessing he may have had a good reason for the design, he's a pretty sharp cookie.

I looked at the manual for breakout board. I'm not seeing how I would connect my remote button for each switch. I have 11 switches on my layout. Would I be able to get a breakout board for each one and have them operated by the remote buttons that come with the dz2500 switches and avoid having to get the LCS module? I have no interest in using Legacy remote control to operate switches. I just want to do it from my control panel with all my remote buttons or just by walking around the layout and pushing buttons directly on 2500 where it sits. Trying to keep it simpler for my kids.

You're confused because the manual doesn't actually represent the current design of the breakout board!!!

Let's look at the actual board.  Note the nice three lead "Push Button" connection at the upper right.  Note the nice "Non-Derail" connection at the lower right.  On the left is all the DZ-2500 wires brought out to the terminal strip.

Of course, if you have the breakout board and wire it all up, running one wire back to the Legacy system will allow you remote control of the switches, something that you might certainly want to do at some point.

@gunrunnerjohn posted:

You're confused because the manual doesn't actually represent the current design of the breakout board!!!

Let's look at the actual board.  Note the nice three lead "Push Button" connection at the upper right.  Note the nice "Non-Derail" connection at the lower right.  On the left is all the DZ-2500 wires brought out to the terminal strip.

Of course, if you have the breakout board and wire it all up, running one wire back to the Legacy system will allow you remote control of the switches, something that you might certainly want to do at some point.

If you have long switches, like No 6, No 8, or curved switches where an engine loses power trying to get through the switch, you will need to alternately power the curved lead rail/straight lead rail using the Z-Stuff DZ-1008 relay (others will work).  The DZ-1008's wires will attach to the left hand screw connections (yellow and green).  You can also attach the DZ-1008 power wires, red to the second hot connection (lower left) but you will have to double up the black common wire to the one Com connection.

For the push button, use can use the connections on the breakout board but my push buttons are pretty far away so they get their power from a separate source.  The white wire from the push button can be connected to the push button connection on upper right, or to the Wht screw on the left.

I'm already planning on the DZ-1008A relays on the double-slip switches (2 DS switches, so four relays), and on my three curved switches.  I tested a few different and typically problematic small powered units on the other switches, and I had no issues.  The other switches are 10x, 20x, O72, and O96 types.  Those all have a pretty short gap between powered center rails.  It's also very easy to drop in the relays after the fact with the breakout boards by just dropping the two wires from the dead rails.  I don't anticipate having to do that, but all the switches are accessible if necessary.  The two O96 switches are the only "maybe" ones, but they didn't present an issue in testing.

I was doing some research on diodes to educate myself and maybe I'm way off base here but it seems that a certain amount of voltage is necessary to get the diode to actually conduct the voltage forward across the semiconductor part. I'm wondering if because the wheels of most railroad cars, when they get onto the isolated rail part of switch, are giving a kind of chattered intermittent connection at best , so when the diode is in there that it just isn't maintaining contact long enough 2 get the voltage to push through the diode. I understand schottky diodes are requiring less voltage so maybe that would work when you're just getting an intermittent Morse code kind of contact with the wheels to rails. Cant find any around so ordered some and have to wait a week, cheap test if it doesn't work out.  If not I guess I'm going to have to go with the breakout boards but that's going to get expensive over 11 switches.

@Johnny B posted:

I was doing some research on diodes to educate myself and maybe I'm way off base here but it seems that a certain amount of voltage is necessary to get the diode to actually conduct the voltage forward across the semiconductor part. I'm wondering if because the wheels of most railroad cars, when they get onto the isolated rail part of switch, are giving a kind of chattered intermittent connection at best , so when the diode is in there that it just isn't maintaining contact long enough 2 get the voltage to push through the diode. I understand schottky diodes are requiring less voltage so maybe that would work when you're just getting an intermittent Morse code kind of contact with the wheels to rails. Cant find any around so ordered some and have to wait a week, cheap test if it doesn't work out.  If not I guess I'm going to have to go with the breakout boards but that's going to get expensive over 11 switches.

You might consider trying the circuit that's on the breakout boards, it's just a standard silicon diode and a 100 ohm resistor.  The resistor is in series with the lead coming from the insulated track section to the DZ-2500, and the diode is on the DZ-2500 side with it's cathode (stripe) to  connected to the DZ-2500 non-derailing lead.

I can attest that the breakout boards are expensive, I have 26 of them, and the total price (I got them from all over) ended up being about $600 for the 26 breakout boards!  The railroading is getting really expensive!

Hi John, let me know if I'm understanding this correctly ...so coming from the isolated rail section wire lead I would then have the 100 ohm resistor, then the diode, then the lead going to the actual 2500 machine.? The stripe on the diode obviously facing rail.

On a little somewhat related side note since it seems the biggest cause of the problem is the lousy conductivity of the Rolling Stock from Wheel to wheel, does everybody experience this? I have about 60 Rolling Stock of various makes and most of them are like this. Am I supposed to be sanding down the wheels to allow better conductivity? For note I have used electronic contact cleaner 2 clean the wheels and the track and it's still intermittent.

@Johnny B posted:

For note I have used electronic contact cleaner 2 clean the wheels and the track and it's still intermittent.

Stop using contact cleaner, it's not suitable for this task, it leaves a residue that picks up more dirt.

@Johnny B posted:

Hi John, let me know if I'm understanding this correctly ...so coming from the isolated rail section wire lead I would then have the 100 ohm resistor, then the diode, then the lead going to the actual 2500 machine.? The stripe on the diode obviously facing rail.

Not quite.  The 100 ohm resistor in series with the lead, and at the connection to the DZ-2500 switch machine, the diode cathode is connected and goes to track ground (outside rail).  That is what is on the CSM2 Breakout Board.

What would be recommended to clean track and wheels?

Mineral spirits is a good choice.

Maybe I'm missing something but I just bought a breakout board from local hobby shop and it does have the new style as in the picture John posted earlier. However the enclosed structions show the old board and do not tell you how to hook up the push button. Also the connector block for the push button on the physical board does not have any labeling to indicate which color wire goes where. I don't want to smoke something, any help appreciated.

Do you own a multi-meter?  That's how I figured it out.   Everything is labeled except for the button connection, here you go.

Well I have now installed the breakout switch and it has the same symptoms as when I installed a diode. So to summarize again what I know... if I test various Rolling Stock for continuity from Wheel to wheel, if it is good then that car will always trigger the non derail even if I have a diode installed or running through a breakout board. If I have a Rolling Stock that shows very intermittent continuity through the wheels then that car will hardly ever trigger the non derail when running through a diode or breakout board. HOWEVER, that very same car with bad conductivity between the wheels, if I run it through the switch with the isolated rail leads connected directly to the leads of the DZ 2500 machine then even that lousy car will trigger the non derail function 100% of the time without fail.

This tells me two things.

1. In a way the fault is in cars that don't have good conductivity through the wheels. 2. something is different when you put a diode in and or run it through a breakout board where that situation will not let those iffy cars trigger the machine.

For note I took some of these bad continuity wheel cars and clean the wheels till no black comes off at all and the rail also and they still act the same way so it's not a case of them being dirty.

Any further thoughts, I can't imagine nobody else is having this trouble.

Sounds like the cars.  I have to admit, I checked half a dozen engines and all had perfect continuity between the wheels.  Obviously, I don't really care much about the rolling stock, I expect the engine has already triggered the non-derailing feature, so the cars just follow.

That is understandable but often times  I am pushing cars and they are the first thing that crosses. Could someone just push a couple different cars  across a dz 2500 controlled switch that is using a breakout board and see if they have this very intermittent trigger of the non derail feature like I am seeing? Then I would know it's not just something weird that I'm doing. I've only tested this in about seven or eight of my cars so far and most of my MTH and Lionel newer cars fail to trigger it. My Menards cars and 40 year old Lionel cars seemed to work just fine however.

You got me, since I'm still wiring my power and switches, I'm not your man.  I'm in building mode right now.  I can't imagine why any modern MTH or Lionel cars with clean wheels and clean track wouldn't trigger the non-derail, so I'll have to take your word for it.

well I took a Dremel and sanded off the dark gray coating on the Wheels. I assume this is a black oxide coating even though it's dark gray. Interestingly, at least so far, I only need to do one individual wheel and it's enough to get decent continuity from Wheel to wheel and it's throwing my non derail switch just fine now. So I guess I just got to do this to about 40 to 50 cars, but it solves the problem. Fortunately all my engines seem to have continuity just the way they are. So that's good I didn't really want to be sanding on those.

What is the brand and vintage of your cars?

Maybe 30 mth built within last decade. About 10 Lionel within last decade.  Those all have lousy continuity. Around 8 Menards..those have perfect continuity. And approx 13 Lionel that were made in 70s...they work fine as is too. I have a couple other K line and Atlas mixed in there but I haven't checked them yet.

Another solution, of course, is to have the switch oriented correctly before you try to pass through!

True but can't trust the wee ones to be diligent on that.

Hello all, I have an update. I received my order of schottky diodes, lower voltage drop, and installed them on a few switches. While it's not a fix all it is definitely an improvement over the regular diodes. I have so far tested about 50 of my cars. To recap the situation .....if I do not have any diodes on the non derail then all my cars work fine triggering it. If I put in regular diodes then out of those 50 about 45 of them would not trigger it, or at best be very intermittent whether it would. With the schottky diodes in there now out of those 45 about 40 of them work just fine now. I have been noticing when I was sanding off the coating that was inhibiting conductivity from the wheels , some seem to be on there much thicker then others so though not a complete fix and I still have a few cars that need to be sanded to work reliably, the schottky diodes do save me a ton of work.

Just to note this coating on the wheels is not dirt or Grime as I have cleaned the wheels very well and it even does this on some of my newest cars I have received that are brand new and probably have less than a half-hour of railtime on them.

Also I would have the same problem with failure to trigger the non derail when using a Lionel breakout board that I was testing out so if I was to use breakout boards I would bypass it for the non derail function and use a schottky diode.