Hi Fred / all

So, I think here is the damn capacitor.......



It is the only thing I see connected to "B" in the TT. Actually, as you can see is underneath the TT

Unfortunately, the other leg, I cannot determine where it goes. It is welded to a wire that goes under that plate, and I tried to disassemble it but can't and I don't want to damage the TT....

Regarding the number, it is really small, but it looks something like 318??. As you know I am not an electrician, so any number sounds the same to me. Maybe to you it means something else. Hope you can see it in the picture....

Thank you!! I think we might be getting closer....

Esteban

Well Esteban,

I'm really glad you succeed. Congratulations !

With the schema below:


...you'll be able to completely wire your TT for automatic processing.

Here are a few explanations and some suggestions:

-This schema uses S88 standard (towards ground) detection for all tracks (bridge included).

-The set of diodes is "the diode trick". It enhances ground conductivity when using locos with small number of axles. The use of diodes is not mandatory, it is only advised. Beware with the diodes, they have a "direction". This direction is shown on the electronic component with a grey or black circle on one side. I've shown it on the diagram (diode 1N400x). Use diodes from the family 1N400x with 1 <= x <= 7 (very common component). Download the doc about the diode trick from Ross web site ( http://members.ozemail.c.../pdf/the_diode_trick.pdf ) and read it, it is very well explained.

-About Peco SL-11 insulators: It's not very expensive (3.5 € for a small bag of a dozen pieces). As the shipping cost to Ecuador may be expensive (from US of Europe), order a few bags to have some spare parts at hand. Peco SL-11 are designed for "Code 100" tracks. It fits well in the spoke track of the TT (just did the test this afternoon). You have to remove the metallic rail joiner of a spoke track with a small flat screwdriver, and replace it with a SL-11 (beware not to hurt you).

-Some problem may arise with the second metallic rail joiner you have to replace with a SL11 (the one fixed on the C-K transition track, at the "K" side) : C-tracks are "Code 90" tracks and I don't have C-track nor any expertise on C-track (I use only K tracks). You have to decide, by first trying to insert a SL-11 on the K-side of the transition rail if it fits well or not. If it fits well, you have won, because you can insulate the 2 "0" rails. If not, you may have to order some K-tracks (2201 = 1/2 straight track = 9cm), and interpose a 2201 between the transition C-K track and the spoke track, then remove from the K-track the metallic rail joiner and replace it with a SL-11. Have also spare transition tracks, just in case...

-Finally, do not plug all the insulated tracks at the same time, then provide power. I strongly advise you to go step by step:
a) insulate the entry track, connect it to the TT (insulated) and S88 and test entry track detection and bridge (facing entry track and facing NO track)
b) add the 1st exit track, and repeat same test; all sections must be insulated from each other; also do a test with a rotation of 180° of the bridge, just to be sure there is no bad insulation.
c) then finally add remaining exit tracks and test again

I wish you good luck, and if needed, ask for help or clarifications.

Cheers
Fabrice

Hello friends,

Time has passed since my last writing on this topic.
A few things have changed, even if the principles of use are still the same as the ones described in post #1.

1. My layout Trossingen has been replaced by Trossingen II, which is larger. Regarding the TT area, there are still one entry track and six spoke tracks.
2. I've replaced the TT decoder (old Marklin ref:7686) by a LDT TT-DEC decoder. The reason was due to a malfunction when the bridge entered a half-turn (180° rotation). Approximately one time over 2, the bridge didn't rotate entirely successfully, and this ruined the automatic sequences and I had also to reprogram the decoder... Does the LDT TT-DEC solved that issue ? The answer is YES !
3. I've progressed in automating the TT area. As I have only one sensor for each block involved (entry block, bridge, spoke tracks), I dug in the Rocrail docs and done many experimentation with the various timers, to find an acceptable solution whatever the steamer entering this area... There are still a bit of tweaking to be done, but the principles are now known.

Reminder and Warning: What is described below involves a turntable dated from 1990-1995 (I don't remember exactly the precise date of purchase). With such a turntable, CURRENT CONSUMPTION DETECTION works for all tracks by only removing the "B" tongue of the spoke tracks, as described in post #1. If you have a more recent TT, current consumption detection may NOT work (See Esteban's long story in previous posts) !!! due to additional electronic components (capacitor and coil) in the TT base.

Here is a shot of the real area:


Replacing the old Marklin 7686 decoder by a LDT TT-DEC decoder has raised an issue, regarding the bridge occupation feedback when using the current detection method. I'm going to provide you the solution if you wish to do such a thing.

Reminder: the LDT TT-DEC provides 2 feedback information: "bridge occupied", and "target position of the bridge reached". The "(target) position (of the bridge) reached" feedback uses a standard ground detection, i.e. standard S88 or LDT RM-88-N or equivalent. I'm going to discuss only the "bridge occupied" feedback, using current consumption detection.

Reminder: These 2 feedback information are mandatory if you wish to achieve automation in the TT area (+ of course feedback from the entry track and the various spoke tracks)

LDT site is very well documented and provide many examples for wiring their various devices. Unfortunately, my case was not (completely) described. After some investigations on various schema, the schema "page 1673" http://www.ldt-infocente...sbeispiele/page_1673.pdf has led me to the solution:
The brown and orange wires of the TT ribbon cable are respectively rail 1 and rail 2 (0 line). The yellow wire is the B line.

As a result, I only need to pick the yellow wire from the TT ribbon and plug it into the current consumption feedback detector.

The wiring schema for such a thing is finally very easy:



The settings in real life is a bit more complicated . The yellow wire of the TT ribbon cable must be left intact, and plugged into the current feedback detector (LDT RM-GB-8-N or Viessmann 5233 or other equivalent). Then, the 6 pin plug of the LDT TT-DEC must be connected to the TT ribbon, except for the yellow wire. To solve that, I've used:
a) a 0,5m extension cable for S88 bus from LDT
b) a hand made interface, done with a small piece of Veroboard, 2 X 6-pin connectors and 5 straps over 6 connected between these 2 connectors. The remaining wire goes to the current consumption detector. Then, plug the TT ribbon cable on the TT input and the extension cable on the DEC output.



Some additional information about MY turntable with the LDT TT-DEC:
After the initial setup of the TT, it worked perfectly !!! except I though the bridge was rotating a bit fast in my opinion (faster compared to the old 7686). I've tried to slow down the rotation speed using the adequate potentiometer. The result was perfect in one direction (clockwise), but in the other direction it was a disaster (not all clicks heared, and the bridge stopped anywhere except in the expected position ). Finally, I went back to the initial settings and left this higher (but acceptable) rotation speed and now the TT works perfectly 100% of the time.

I'll discuss later the various tweaking of Rocrail and provide more examples for automating the TT area. To summarize, the most critical part involved in automatic sequences in the TT area is the ENTIRE placement of the steamer ON the bridge, before the rotation starts. To achieve a good placement, a loco must have set its own timer for this block (the TTBridge block). The various parameters of Rocrail for a loco object provides such a timer. This timer is used by default if it has a non 0 value, instead of the block timer.
Each loco going in this area will have a different timer value, depending of the mechanic, the loco decoder tweaking, the "slow speed" value, and the position of the slider when using current consumption detection !

Stay tuned for more information...
Cheers
Fabrice

When testing my BR64 I found it makes a slight buzzing sound which becomes louder when on the turntable.
I decided to remove the capacitor and inductor from my turntable.

It was a royal pain in the ass to do since my turntable is installed, even with the centre being accessible.

To access the inductor you need to remove the capacitor, de-solder all the wires and then remove the plastic cover.
Here is that work performed with the inductor now exposed:



After removing the inductor and re-soldering the wires (now with yellow on the centre pin which was previously soldered to the inductor leg) here is what it looks like:



After re-testing I found no change with the buzzing noise of the BR64 so I am not sure if this work has helped me at all.
I will be using S88 detection for my turntable, rather than current detection which is what other users had problems with.

Edit: I also cut off the centre strip 'tabs' that stick out from the turntable that provide power to the spur tracks in analogue operation.
Since I run digital it was not required and also caused problems as it could occasionally make contact with the rails during rotation, resulting in a short.