# DCC Wye reverse loop controller problem



## DonR (Oct 18, 2012)

After 3 or 4 months of trouble free operations
suddenly I'm getting a short circuit when
power pickup trucks span the insulated joiners
at a certain spot. Oddly, it works fine when
locos enter the 'isolated section' from the
main layout, but when they bypass the
isolated section to the bottom tail track thru
the right track of the wye and
then go up the left track...a short occurs at
the insulated joiners. 

I tried adjusting the 'sensitivity' to no avail.
I checked the wiring for incorrect polarity. All OK.
I replaced original controller with a good one. Still shorts.
No changes had been made. The insulated joiners are
still insulating. So what have I not done?

I have a classic WYE...to describe it:

Turnouts A & B are across the top. Turnout A 
on the right is the track to
rest of layout. Turnout B on left is to dead end tail. Turnout C is
at the bottom and another dead end tail. The insulated joiners
Isolate the straight from A thru B and the dead end tail. A 2nd
set of insulated joiners are between turnout B and the track
to the bottom of the Wye turnout C: When power pickup
trucks span those joiners I get a short. (in one direction)

Main layout power buss feeds thru A and thru C and
back up to insulated joiners before B. The isolated
section is powered thru a Bachmann reverse loop
controller which is powered by main buss.

Why a short at those joiners only when loco approaches
from one direction? And why did it operate smoothly 
for months?

I've run out of things to check...help.

Don


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## NIMT (Jan 6, 2011)

Is this what you have set up?


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## waltr (Aug 15, 2011)

is the isolated section of the Wye (NIMT's drawing above) power with a DCC Auto-Reversing module? Which one (make and model)?


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## DonR (Oct 18, 2012)

NIMT

Using your drawing which is very close
to actual layout wye: 

There is only one difference.

Both rails have insulated joiners
between the Left turnout and the straight track across the bottom.

Both rails have insulated joiners where you show them on the
right turnout.


The layout is powered by Bachmann DCC and the reverse loop
controller is also Bachmann.

The odd ball thing here...the wye worked as it should for
several months...began shorting a week or so ago.

Don


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## RT_Coker (Dec 6, 2012)

Hi Don,

I have had a lot of strange trouble with the Bachmann 5 Amp booster and the Bachmann auto-reverse competing with each other. Everything can be working fine and then a small thing like more loading (multiple locomotives) and the two units start chattering at each other. I finally went with the auto-reverse’s supplied wires and connections per the manual. Since then I have not had any trouble. You might what to try this with your setup.

Bob


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## DonR (Oct 18, 2012)

Bob

I'm using the power block that came with the EZ Command
DCC controller...it doesn't have the 5 amp booster.

I had a spare reverse loop controller and replaced
the original thinking it may have gone defective...
but I get the same shorting.

Doesn't seem to be a conflict between the 2
controllers. There is clearly a short circuit when
a power pick up truck spans that one
insulated joint.

The problem is a nice brain tease.

Don


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## NIMT (Jan 6, 2011)

Is this it? If it is then I would say you have the possibility for 2 problems.
#1 The reverse loop controller has failed, you did say it was working for a month or so. (This is my pick)
#2 One of the two switches (left or wye) is got a problem with it.
To eliminate that posibility, remove just one switch at a time and run the trains across the transition that's left and see if it shorts out.
If possible switching to the layout of the insulated rails in the first pic is a better setup (only one switch in the isolated reverse loop).








Edit: :sly: Your post while I was typing makes it sound more like option #2!


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## NIMT (Jan 6, 2011)

NEWS FLASH!
Please just answer the first Question in the last post first!


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## DonR (Oct 18, 2012)

Nimt

Yes...the last drawing is exactly where my
insulated joiners are BOTH RAILS.

Logic says something changed since it operated
without trouble for months.

Per request...I'll hold there for the moment.

Don


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## DonR (Oct 18, 2012)

I'll go ahead with another comment.

The turnouts are code 100 Peco Insulfrog...

The reason I wired the Wye as I did...using your drawing...
the track to the main comes in through the right turnout.
The most traffic thru that turnout is to my passenger station
which is on the bottom tail...so I thot to avoid all the
reverse loop controller working...Initially I had thot to do
it the way your first drawing shows but changed for
the reason stated.

I'll have to recheck, but I believe due to Peco power
routing, if the Bottom turn out is set to straight there
is no power in the track from it to the turnout on the LEFT.

Don


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## NIMT (Jan 6, 2011)

The answer is going to floor you. You had a bad connection and you fixed it and now it shorts out!
You MUST move the isolation section to be like the second picture here.

Wrong way and shorting!







Right way!


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## NIMT (Jan 6, 2011)

And power routing In DCC is a problem. it's best to not use it and to feed power to all sides of the switches!


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## DonR (Oct 18, 2012)

I found the bad guy.

NIMT

Your mention of possible turnout problems triggered me
to hook up my trusty Harbor Freight V/O meter to the
isolated section reading DC voltage. I got a + reading

I found when I flipped the right hand turnout to
the across the top isolated track the reading turned to -
good ole Peco power routing strikes again.

Close inspection and there it is...expansion pressed
the rails together over the insulated joiner...

It was shorting the main Buss to the isolated buss
when the Peco was set to the isolated section...
and that is why the system worked when loco approached
the other insulated joint going from main to isolated
it did as was supposed...but going the other way
it shorted. And explains why it was working fine but
suddenly did not.

This has to be an unusual happening...and something else
for DCC guys to check when there is
a problem...are the insulated joiners INSULATING.

Now gotta undo what the gremlins did.

Do thank you and the other guys for your help.

Don


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## DonR (Oct 18, 2012)

NIMT 

Sure wish I had that ability to computer draw...your
diagrams are so easy to read.

Guess you see that I found the problem which was
a defective insulated joint that was shorting Main
to Isolated track when Peco's power routing was on.

I felt it had to be some off the wall thing like this since
the system was working fine until it didn't.

I have long ago done what you suggest...I have drops
on all of my tracks affected by power routing...otherwise
the trains would be dead half the time.

Might add CHECK THE INSULATED JOINTS to your
DCC problem check list. 

Thanks again

Don


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## NIMT (Jan 6, 2011)

Excellent!:thumbsup::thumbsup: Glad to hear you got it going again and bonus no cost to repair. 
I will add "insulatted rail joiner to my trobleshooting list! 
I dont use insulated rail joiners, I screw four small brass flat top screws in the roadbed on the centerlines of the rails, 2 each side by side, just high enough to miss the bottom of the rails then I set track over the screws, Removing ties that get in the way, I solder the rails to the screw heads then cut the rails between the screws that way they can not move and short out. I have a friend that will even epoxy the gap in the rails.


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## DonR (Oct 18, 2012)

First time I ever that kind of insulator mishap...anyhoo

I took your advice and now the Isolated track is the Y
part below both turnouts...and no complaints
from the controller.

What d ya mean no cost...how about my psyche?...
(or is that psycho?)

Don


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## NIMT (Jan 6, 2011)

Your into Model Railroading... Thats a given! :retard:


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## Kilian (Feb 27, 2012)

This is what scares me off of starting my model railroad. The electrical. 

My layout is like the letter Q. Round with small point for a yard. I assume to use a wye to connect for a mainline to the yard.


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## DonR (Oct 18, 2012)

Kilian

Electrical problems are part of the fun of trains...but DCC
makes it easier...

And the guys on the forum are going to guide you
thru whatever puzzles you...enjoy it.

You'll be learning a whole new aspect of life...the
ins and outs of electricity...what you find out can help
you with vehicle and home problems later...

If you have a wye...you must isolate it...and power it
through an automatic reverse loop controller. 

I'm curious about your layout SHAPED LIKE THE LETTER Q.

Don


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## NIMT (Jan 6, 2011)

Kilian,
Your only 5 hrs north of me, and I do make house calls!:laugh::laugh::laugh:
Seriously DCC wiring is easy and 99% of all problems can be solved with a quick converation.


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## Kilian (Feb 27, 2012)

NIMT said:


> Kilian,
> Your only 5 hrs north of me, and I do make house calls!:laugh::laugh::laugh:
> Seriously DCC wiring is easy and 99% of all problems can be solved with a quick converation.


Awesome. Thanks NIMT!

Do you ever attend the Calgary Train http://www.supertrain.ca/. In April?


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## NIMT (Jan 6, 2011)

I'm planning on coming up there for this one, just to check it all out!


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