Updated 14.01.2010
Märklin 43410 and 39420
The 43410 is originally fitted with a white and red front lights, changing with the driving direction. I was not very happy with the light installation. The front light, either the red or the white, was on all the time. In addition, the light changes when the car starts moving, not when the direction of the pulling/pushing locomotive is changed. The light is controlled by a mechanical switch in the bogie.
A number of SBB cars are supposed to run in the same train as the 43410, all with interior light. As I wish to control the interior light with a decoder and a relay, I decided to install this in the front end of the control car, as this car already has a pick-up shoe.
The originally fitted printed circuit board. The two parts next to the car was installed in the front bogie, the orange and the black wire was soldered to the to soldering pads in the middle of the board. The brown and the yellow wires come from the bogie in the other end of the car; the brown is "0" (wheels) and the yellow "B" (pick-up shoe). I did not want to alter any of these parts, so I carefully removed them and store them safely.
The new printed plate, that has to be lifted one millimetre up from the floor. It is too thick to fit as the original board was fitted.
As all the parts will be installed in the driver's end of the car (front end), I moved the pick-up shoe and the ground connector to the front bogie.
New circuit board
The new board will be used for LEDs and their dropping resistors, as well as a
distributor for the orange wire from the decoder (+). By carefully aiming
it is possible to find the location for the four LEDs, compared with the original
circuit board. The three white LEDs are connected in series, with a 510 Ohm
serial resistor. The red LED has a 1,5 KOhm resistor. The interior
light in the driver's cab is also soldered to the board. The LEDs I use
are a bit bigger than the original ones. The camera did not catch the
colour difference between the white (or rather yellow) and the red LED.
The relay
A small one-pole relay, that just fits under the interior, inside the area of the
original circuit board, when I bent the contact pins down. It's approx. 7,3
mm high.
Left upper pin = contact output, current to the connected cars, red wire to the
current conducting coupling
Left centre pin = coil input, brown/red wire (-) from the decoder
Right centre pin = coil input, orange wire (+) from the decoder via the circuit board
Right lower pin = contact input, red wire from the pick-up shoe
A drawing of the board is in the bottom of the page.
Decoder:
I installed the 60961 decoder in a decoder holder, Märklin part no. 285820, on
the steel plate under the interior, between the front doors. I cut out the
floor of the interior between the doors, so the interior fits perfectly over the
decoder an all the wires. The wires must be spread out flat, to fit under
the interior.
With the interior installed:
The decoder functions:
| f | wire colour | function |
|---|---|---|
| f0-f | gray | one red light at the car end |
| f0-r | yellow | three white lights at the car end |
| f1 | brown/red | interior light in the connected cars, via the small black relay |
| f2 | brown/green | interior light in 43410, via the two-pole connector on the board and a 1.500 Ohm resistor |
| f3 | brown/yellow | light in the driver's cabin |
| f4 | brown/white | not connected |
Interior light in the control car:
The interior light in the 43410 itself is controlled with f2, brown/green wire. Two 73400
LED light units is used. It gives a rather warm light colour, but I am not
fully satisfied. I experimented with a home made light unit, using 28 Volt
normal bulbs. I like this light better, but the power consumption is far
higher than the approx. 30 mA the two 73400 units consume. I soldered two
wires to the 73400-connector behind the driver's cabin, and connected them to
the two-pole connector on my home made circuit board. The light colour is rather warm, but in my opinion it is
too bright. So I installed a 1,5 KOhm resistor in series with the
brown/green wire (function f2) from the decoder to the light units.
Perfect. And the current consumption went down below 10 mA.
A photo will follow later.
Light to the connected cars:
The interior light in the connected cars is controlled with f1, via the relay. I have not
installed light in the other cars yet. I will probably go for the 73400
units, except for the luggage car, where I wish to illuminate only parts of the
car.
The red wire from the pick-up shoe is distributed to the relay contact and to
the decoder. The other end of the relay contact leads to the conducting coupler
in the other end of the car (single red wire under the steel plate). The relay
coil is connected to function f1 (brown/red wire from the
decoder) and to the orange wire from the board.
Note: the driver's cab normally sticks to the car body. I just removed it for examination and to cover the light guide with thin insulation tape, to prevent the driver's cab light spilling to the upper front lamp. At the same time I glued a man to the seat. He became a bit too high, but I find the removal and installation of the cab rather tricky (easy to brake the light guides to the lower lamps), so I leave him as he is.
I will report when the interior light, people and so on are installed in the other cars.
Wiring diagram:
The LED circuit board looks like this:
My
plan is to run the train like this:
39420 SBB Re 4/4 I 10 015 locomotive
43400 SBB D 18926, luggage car
43380 SBB B 6124, 2nd class car
43360 SBB A 2231, 1st class car
43390 SBB WR 10121, restaurant car
43370 SBB B 5581, 2nd class car
43410 SBB ABt 50 85 38-33 930-2, control car, 1st and 2nd class
I know that the control car ABt is not supposed to be here (wrong era), but I think it looks good anyhow.