Hi All,

I decided to mount an ESU function decoder into my 43832 "Silberling" cab control car, as well as interior light in all three cars in the consist. First I just wanted to control the interior light in the consist, however suddenly the idea of controlling the head/tail light and separate controls for the interior light in each of the 3 cars became a small project. This is the functions I got now:

F2: Headlight/taillight on/off
F3: Interior light in cab control car on/off
F4: Interior light in 1/2 class car on/off
F5: Interior light in 2 class car on/off

I this current simple version the function decoder controls 3 relays. The first relay switches the power for the head/tail light PCB in the cab control car, the switching between head and tail light is still controlled mechanically without any changes made.
Interior light in the cab control car is driven directly from the function decoder.
The trick was get two function outputs through the normal one pole current conducting coupler, without adding separate decoders in each car. Two relays controls the power to the conductive coupler, one relay with a diode provides the positive half of the from power provided by the slider, and another relay the negative half. The cars controlled this way are then fitted series diodes an capacitors to avoid flickering. This direction of diode selects the channel.

Hi Kimball,

The function decoder I used is ESU's 52620 function decoder, it has 6 outputs, each 250mA, total 500mA max. It runs both Märklin-Motorola and DCC protocols. The price here is around €20 incl. GST. Basically it is a Lokpilot without the motor controller part, so it's cheaper and a bit smaller.

Hi John,

Here is the schematic, I'm considering making solid state version bases on the same idea.

Hi Anthpao,

Thanks for your comments. I fully understand what you are saying, however my goal was to achieve two independent function outputs over a single pole conducting coupler. If you have a look at the schematic in post #5, you see the power to conductive coupler (J3) is controlled by two relays (K1 & K2) and two diodes. This way makes it possible to control whether provide the positive and/or negative part of the AC cycle is powering the consist via the coupler. The two cars connected to the cab control car are then “programmed” by placing a diode in series the LED bars, the direction of diode then controls the “channel”, positive or negative. Each car has it’s own ground spring, these cars would also work in any other consist with power provided from the pickup shoe, thus being compatible with the standard Märklin use of conductive couplers. I add a capacitor in each car to avoid flicker, since each car is only gets power from half a cycle.

I fully agree with you and John, regarding the programming – re-assigning the function, and changing the address to same as loco normally used in the consist. However I kept the mechanical switch in front truck for changing between head and tail –light, since I felt it’s doing the job well, and keeping it this way makes it more independent of loco used.

This is what I would like to do, except that I will use the trailer car with at least 3 different engines.

So I guess I program this decoder on a programming track, allocate an address, and choose on/off funtions for F whatever. Is that correct?

I am ignorant of these electronics, because all my decoders usually come installed by a factory in Goppingen, Germany.

regards
Kimball

Thanks Pål,

I just want to add a couple more details about some of parts I used, many times train projects.

Relays very small: Tyco Electronics, TSC-112L3H000, RS components #493 6745, UK price £1.81 ex. VAT
http://uk.rs-online.com/...=4936745&x=0&y=0

LED interior light from www.hufing-tronic.de warm white 230mm LED PCB with 7 LEDs and adjustable with trim pot, I bought them for for around €5 on Ebay.de , that is 25% of Märklins price, but there no plast bracket or double adhesive included. By they lots LEDs models.