DCS Signal Problem Solved?

Pat,

If I understand you correctly, the bottom line is that you did 2 things:

• Changed from Passive mode on the hidden staging area to normal TIU mode.
• Swapped Z4000s between the two channels.

Is that correct?

Pat,

  Electronics don't you just love it, got no advise for ya as to why it fixed your problem, unless your TIU is working intermittently. 

PCRR/Dave

The gremlin left the electronics, pure magic, ever hear of murphy's Law!

if a thing can happen it will!  !!!!!!
Alan

I wonder if there's a better common on the tiu channels with the way it works now ... We know the  Z-4000s are phased together via the track common but this can be lost at switches . insulated sections . Are the transformers common tied together??

Barry:

You  got it right.  And the problem does not reoccur if I go back to passive mode on the hidden staging channel.  I went back to normal wiring so I regained the availability of emergency stop.

Any ideas?

Pat,

Any ideas?

Not a one.

The only explanation that I can offer is that something else occurred and then "un-occurred", of which you're not aware.

If there truly is a sustaining issue, you can be certain that it will resurface.  

Hi Pat, it is possible that there was a poor connection on a ground circuit.  I use semi-passive, feeding hot through the TIUs but ground bypasses the TIUs, with all black outputs connected together and tied into the ground buss that runs around the layout.  I have had soldered wire connections fail (my grandgremlins like to duck under the layout and pull wires too hard) and black TIU terminals get loose, with the result an impaired signal. 

I tend to think that Gregg is on the right track.

I only tested passive mode once outside on my G scale. The signal strength went down and that was it for me.

So the problem is I never found out why or remember exactly what was being used. I saw a recent post about adding something to the circuit when in passive mode to help the signal. I should have copied that post!

 It never occurred to me to add anything if a version L TIU was being used. I would like to figure this out so I can run bigger consists!

As far as this post, troubleshooting can be a lengthy process, made even longer when the problem is intermittent.

I run 2 Lionel tank cars with sound. They usually are no problem. One day this past year, my trains were acting up. I pulled those 2 and things got better. I don't think they are to blame. At times like that, it's what fixes the problem seems to be the cure. You still have to find the problem.

Barry & Robert:

Thanks for the feedback.  I’ll try to remember this episode if (when?) this rears it’s ugly head again.  

This is the kind of thing that lends credence to my belief that Murphy was a model railroader.

Interesting. Did the equipment on the tracks change? Loose connection?

I had the same problem go here this may help.

https://ogrforum.com/...ignal-voltage?reply=

Gregg & Robert:

Thinking about the things I’ve done to the layout during it’s 8 or so years in operation, I believe you may have hit on the issue.  I’m extremely lucky to have stumbled onto the solution as I seriously doubt I could ever have traced the grounds (commons?) that caused the problem.

Over the last 3 years, I’ve retrofitted computer operation of the layout which utilizes many isolated outer rail sections to track the locations of the trains.  Sadly, when I built the layout I didn’t realize the value of consistency in choosing which outer rail to wire as common, or wiring both outside rails as common.  Isolating sections required some kludges to keep one common rail and still be able to isolate a section on the opposite rail.  Sometimes I’m amazed at how well it actually works.

Thanks again for your input, it’s been very helpful.

One thing that was discovered in several different test locations is the addition of a 22uh choke between the transformer and the track (and TIU connection) really helps in passive mode.  Basically, you're wiring the 22uh choke to isolate the transformer from the TIU and track connection.  It appears that some transformers adversely affect the TIU signal in passive mode, no big surprise there.

Pat, I have found that with electronics things happen.  There must always be a reason, but sometimes that reason cannot be easily discovered.

I have two TIUs on my layout, each fed from different transformers.  Certain softkeys sometimes cause the triggered events to happen twice, a condition that goes away if I turn off the other TIU,  There is no electrical interconnection, other than they both have the same layout ground.  MTH's only suggestion was that there is possibly inductance between two circuits.  Years ago, it only happened in one spot on the layout, and now all over.  I call it the doubletoot syndrome, because its most obvious on the whistle signal buttons.

Pat,

After spending way too many hours trying to troubleshoot problems (I am lousy at it). I have reconciled myself to this thought.  If the problem suddenly goes away then I don't look a gift horse in the mouth, I humbly thank the gremlin who made the problem go away and move on in peace (until it happens again).

Ed