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Offline luckas  
#1 Posted : 15 June 2022 11:02:54(UTC)
luckas


Joined: 06/02/2002(UTC)
Posts: 191
Location: ,
Greetings,

I have a 7286 with the digital decoder (7687) and controlled using software through a CS3.

The turntable works well in automation, but operates normally only in one orientation. When rotated 180 degrees, the contract tracks inside my engine sheds are 'activated' even if there is no locomotive inside.

The issue seems to be 'electrical' in nature, rather than a software issue.

The entire length of the turntable 'block' is a 'contact track', and each of the engine shed blocks also utilise a contact track.

Again - all works fine in one orientation, but when rotated 180 degrees, the turntable 'trips' the empty contact tracks in my sheds when positioned on each.

It's a long shot, but I wonder if anyone can suggest an explanation?

Paul
Offline JohnjeanB  
#2 Posted : 15 June 2022 15:15:16(UTC)
JohnjeanB

France   
Joined: 04/02/2011(UTC)
Posts: 2,080
Location: Paris, France
Hi Paul
Not sure which s/w you are using.
BEWARE: the 7286 has track contacts (3 at each end of the bridge) to power the access track where the bridge has stopped. If not bent or cut, the bridge may activate (renders occupied) an empty track shed. This is because at least one of the bridge tracks is connected to ground and can transfer -through these contacts) this ground connection to the access track thus making a fake occupation.

Here is the little I know, using Rocrail and a DSD2010 decoder (different from your decoder) with a 7286 TT:
- the TT is 48 position and the s/w has to manage 48 positions otherwise the loco may exit the bridge on the wrong side.
- when executing a schedule (a succession of blocks used to travel from A to B) when stopping on the bridge, the loco direction is updated depending on whether an exit on the smae bridge side is required or not
- for each access track, there are TWO ROUTES to access the bridge: one to enter the + side and one to engter the - side and with Rocrail I had to lock one of the 2 to minimize the bridge rotation
- the bridge has 3 detection zones allowing a precise stop of long locos while

Here is a video a my layout with Rocrail, a CS2 and digital automatic operation

It seems to me that some simplified operations (like 24 track management) are for manual operation (you know which side the loco must leave the bridge) and not nworking in totally automatic mode
Cheers
Jean
My layout videos
latest vid
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thanks 1 user liked this useful post by JohnjeanB
Offline luckas  
#3 Posted : 16 June 2022 08:02:46(UTC)
luckas


Joined: 06/02/2002(UTC)
Posts: 191
Location: ,
Hi Jean,

Thanks for your ideas. My engine shed tracks are powered separately, and the track on the turntable is not powered unless it is connected to the entry or exit tracks, but only in one orientation. At 180 degrees the turntable track does not receive power from the engine shed side, only from the main line side, and it trips the contact tracks in the engine sheds.

I think the 'good' side of the turntable has had the electrical contacts cut to prevent what you describe above. I must have done this years ago, but I can't remember. The 'bad' side is still electrically connected to provide the turntable track with power.

I think I've solved the problem. I wonder if there's a way to provide power to the turntable track separately, and remove the electrical connection from the remaining side?

Paul
Offline JohnjeanB  
#4 Posted : 16 June 2022 12:39:31(UTC)
JohnjeanB

France   
Joined: 04/02/2011(UTC)
Posts: 2,080
Location: Paris, France
Hi Paul
Originally Posted by: luckas Go to Quoted Post
I think I've solved the problem. I wonder if there's a way to provide power to the turntable track separately, and remove the electrical connection from the remaining side?

In the Fleischmann / Märklin 7286 turntable (with a multi-colour flat cable, the bridge track have 3 cables for connection
Here is the assignation of the contact rings on the TT
7286-plot central.png
and the cable colour for the track are
- Brown one lateral rail
- Orange other lateral rail
- yellow: "center rail"
The other 3 cables are a link with the remote control
7286 Cable colour assignment.png
Since you are using the 7687 you may notice:
- B plug to connect the bridge's center rail
- O plug to connect the bridge's left rail
- O plug to connect the bridge's right rail
Here is a link to the 7687 users manual https://static.maerklin....876e4b34bc1574773383.pdf
I hope this helps
Jean




My layout videos
latest vid
hump yard
Offline luckas  
#5 Posted : 16 June 2022 12:47:59(UTC)
luckas


Joined: 06/02/2002(UTC)
Posts: 191
Location: ,
Thankyou again Jean,

As far as I can tell everything is connected correctly. Now that I think on it some more, I'm pretty sure I modified one of the ends of the TT centre track (ie, disconnected the O) in order to isolate it from the engine shed contact. That would explain why turntable shorts the shed contacts when rotated 180 degrees.

What I don't understand is why my TT centre track is not powered unless it's connected to an entry or exit track. I thought the B-0-0 connections would supply power to the TT track continuously.

I need to dig a bit deeper.

Thanks again,

Paul
Offline JohnjeanB  
#6 Posted : 16 June 2022 13:37:41(UTC)
JohnjeanB

France   
Joined: 04/02/2011(UTC)
Posts: 2,080
Location: Paris, France

Paul
Originally Posted by: luckas Go to Quoted Post
What I don't understand is why my TT centre track is not powered unless it's connected to an entry or exit track. I thought the B-0-0 connections would supply power to the TT track continuously.

There may be mutiple reasons why the centre track is not connected:
- the cable to the center pivot is not connected broken
- on the bridge, when the conducting plates have been removed (central screw), there is a contact blade to link the conducting plates with the central pivot. If absent or bent, there is no power feed.
Sans titre.png
In the red oval, there is a contact blade with a hole in the middle. If absent or not bent properly, no power will arive to the "center rail"

After many years of using the 7286 TT, I strongly advise NOT to use the extremity contacts. They cause noise, friction, contact issues. So it is best to cut them off or to bend them so that they cannot touch anything. The bridge must receive power directly
Cheers
Jea


My layout videos
latest vid
hump yard
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