Wiring Express models lights to R7146 TTS Decoder

[benson132]

Bought and hard wired up  - only white lights come on. There is a spare purple wire from the centre of the board (not the aux cab light connection) but no purple wire from the TTS decoder. Any idea where the purple connects to?

[Chrissaf]

TTS Decoders do not support the 'purple wire' (fourth function).

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TTS only support three functions.

First and second function is the 'directional lighting' on the white and yellow wires and a third aux function on the green wire

[96RAF]

Most Express Models kits can be rigged to allow for 4 function operation or 6 function operation. In the event of 3 function like TTS then Aux (say both cab lights) are controlled by the third (green wire) function.

 

The instructions provided always tell you which wires to connect together to enable simple directional lighting whereby the front whites and rear reds are on according to direction selected. I don’t have any instructions in front of me but essentially End 1 white lights wire connects to End 2 red lights wire (to switch the negatives) and vice versa for the other direction of travel, with blue as the common positive supply.

 

In the event you want separate lighting control of the front and rear lamps, such as day/night running or light engine/train rake 

running, then you need a more capable decoder as Chris said.

 

Edit - Be aware to stay within the TTS decoder function output limits you may have to add an additional 1K ohm resistor in the blue wire.

[Chrissaf]

In the event you want separate lighting control of the front and rear lamps, such as day/night running or light engine/train rake  running, then you need a more capable decoder as Chris said

.

It is assumed that the Express Models kit is the Hornby 08 kit, but that assumption is just because the R7146 is a Class 08 TTS. Thus there will only be cab lights at one end. The Class 08 Express Kit is designed around a four function decoder (this statement based upon the contents of the kit instructions), which the TTS is not.

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I have a copy of the 'Express Models' instructions for the Hornby Class 08. Based upon what I have read, it does (if I have read them correctly) indeed digress from the normal 'Directional Lighting' control and implement separate front and rear control. It is not a well written document and not an easy read that provides total clarity......'it is vague' is an understatement. The instructions are written with an assumption that the reader has the physical product in front of them to look at and compare to the written text, so this does not help much when trying to offer 'third party' support advice, where only the text is available for reference.

[96RAF]

Just reading through the Class 08 instructions, which as Chris says are dire. Why not just provide a simple wiring schematic.

 

The running lights are one red led (blue and red wire) and one yellow led (blue and yellow wire) at each end. The longer wires go towards the cab end.

 

It is assumed (by me) that the 08 being a shunting engine could have all lights on at both ends all the time, hence why the instructions tag the various lights to F0, F1, F2 and F3 (function operating buttons not decoder function outputs).

 

The cab light(s) has white and blue wires which they say attach to the same coloured flying leads wires on their lighting unit.

 

The instructions advise removal of the DCC socket so as to allow hard wiring the decoder in. If you wish to and space allows you to keep the socket, then the flying leads from the lighting board attach to blue, white, yellow and green (inner four) pin allocations at the DCC socket per convention.

 

This is where the confusion arises as the instructions advise against using directional lighting connections else all lights will come on together, as you would expect given the way they have configured their lighting board. They also say the lighting board tells of which decoder wire attaches to where - a picture would help. The one in the instructions is not clear enough for me to read.

 

My advice for use with a TTS decoder would be to wire the front yellow and back red light to the socket white pin,  the rear yellow and front red to the socket yellow pin and the cab light to the socket green pin (worked by F25 button) with all the blues together to the socket blue pin. I have no idea what lights the purple wire works in the kit, but on a normal 4 function decoder it would be worked by F2 and could be another cab light or work a relay for train red light or not.

 

I hope this helps...

[Chrissaf]

Just in case it isn't obvious in Rob's post. I sent him a copy of the Express Models Class 08 instructions to review and that is what his comments are based upon.

[LMSFan72]

I don't have express models lighting but I am about to add lights to my 08 TTS. I have decided that it basically has 2 jobs: shunting and may be a little mainline work.

 

If mainline then I would always be pulling even if cab end was forwards so I will connect only white lights to yellow and white. For shunting mode I will use all lights - red and white on at both ends irrespective of direction, so I will use green for that connecting to all of the lights. I will use diodes in line on the negative function wires (white, yellow, green) to protect them. Cab light I will not use, but, it could be wired to either of the other scenarios - most likely the green. It is important to lower the current draw with so many LEDs on one function with resistor - as Rob'a earlier post suggested.

[96RAF]

I guess before installing the lights you first need to define what you want them to do. My post above was based on how I would be running such a loco. LMS72 has come up with a different scenario. Benson132 may have yet another variation of need.

[benson132]

Thank you guys will experiment John

[96RAF]

Just remember the function outputs are not self protecting and limited to a max of 100mA each within the overall decoder limit of 800mA.

Exceed at your peril, well the decoder’s peril.