Circuit Diagram with updated lighting

The updated arrangements use two decoders to provide independent control of forward and reverse, day or night running lights in the two cars. Flood lights and warning strobes are added. The wheel contact connections for each car are coupled together and fed to both decoders. The motor is driven from the power car decoder.

Modifying the Running Lights:

Showing how the new headlight chip LEDs and shroud extensions are fitted

The shroud extensions are made from thin plasticard and painted gloss black to prevent marker light leakage into the unused headlight lens.

Close up of the power car lighting PCB assembly

Showing the diodes and headlight series resistors (functional but not pretty)

The model is only going to be used in DCC layouts. This makes most of the Bachmann circuitry on the power car decoder board and on the trailer car lighting support board unnecessary.  Without a lot of track tracing, I don't know exactly how the Bachmann circuit operates. To be safe I will therefore remove all the SMD parts and add links where required to make the essential connections between the 21 pin decoder connector, the track contacts, the lighting PCBs and the motor. I also need to add 21 pin connector Aux1 and Aux 2 function output wires, which are not included on the original PCB. 

Interesting! I haven't found a track connected to the decoder common positive pin...... looks as if maybe the positive connection for the lights was derived directly from the track connections via the on-board diodes. I'll just link directly to the 21 pin connector and drive the modified lights in the conventional way (as shown in the circuit diagram).

Changes to the Decoder PCB:

All SMD components are removed, leaving just the two coils in series with the motor. The motor connections and track contact connections still route correctly to the 21 pin connector. The White and Yellow function outputs are accessible on two pads on the rear of the PCB. Three new link wires are needed as indicated below. The speaker contacts at the bottom of the PCB still connect to the appropriate decoder pins.

21 Pin Connector side: New links are needed for Com +ve, Aux1 and Aux2 to the pads indicated at the bottom of the PCB.

Other Side: The Pads indicated become the White and Yellow Function Outputs

Programming the Power Car LokPilot Decoder:

The wiring connects to the function outputs as follows:

       White : Right Hand Day Headlight.

       Aux1 : Left Hand Night Headlight.

       Yellow : Rear Lights.

       Aux2 : Flood lights on the spray Module.

The control buttons are as follows:

       Button Zero: Day running (Day headlight fwd; rear lights bwd).

       Button 1: Night running (Night headlight fwd; rear lights bwd).

       Button 5: Floodlights on spray module.

       (Button 6: Strobe warning lights on FL4 decoder in trailer car)

New Day Running Lights on Power Car

New Night Running Lights on Power Car

Programming the Trailer Car TCS FL4 Decoder:

The wiring connects to the function outputs as follows:

       Green : Right Hand Day Headlight.

       Purple : Left Hand Night Headlight.

       Brown : Rear Lights.

       Pink: Strobe warning lights.

The control buttons are as follows:

       Button Zero: Day running (Rear lights fwd; Day headlight bwd).

       Button 1: Night running (Rear lights fwd; Night headlight bwd).

       (Button 5: Floodlights on power car spray module.)

       Button 6: Strobe warning lights.

Amber double strobe warning lights are mounted on the roof of both cabs, driven by the FL4 decoder in the trailer car.

Showing a strobe warning light before painting, glued to the trailer car cab roof.

The series resistor is split to provide fixed anchor points for both supply wires. 470 ohm resistors are connected on each side of the LED and are glued to the inside walls of the cab.

One of the 470 ohm series resistors glued in place & soldered to a LED wire.

The strobe housings were painted yellow and the visible enamelled wire on the cab roofs and the spray module roof were painted grey. Finally, the coupling hardware, brake hoses and access steps were super glued to the front of each car. 

Trailer Car now fitted with the "add-on" bits. (I've since re glued that white step down a little!)

I found a Youtube video demonstrating the Howes LokSound decoder with the MPV on a rolling road.......  The motor sounds, warning sirens and spray sounds should add quite a lot to the entertainment value. So the next job is to order a Howes decoder, fit a speaker and work out the CV programming changes needed to combine the lights and sounds.

An ESU 50334 40x20mm 4 ohm speaker was mounted within the the under-floor box of the power car. The bottom of the moulding is heavily contoured with the shape of the rear bogie motor drive components. Some surgery was therefore required to achieve a suitable flat flush speaker location. A simple thin plasticard frame was then added on the inside, to mount the edge of the speaker, ensuring adequate clearance between the speaker cone and the remaining parts of the floor below the speaker. The speaker was glued and sealed in place using "Glue 'n Glaze". There was not sufficient room to include the standard speaker enclosure. Instead, an air tight seal was created around the speaker rim and the air gap between the box and chassis was minimised, converting the under-floor box into a semi-sealed speaker enclosure.

Speaker installed in power car under-floor box.

The night running lights will be shifted from button 1 to button 2 to avoid disturbing the standard sound start-up button on Bryan's Howes LokSound decoder. This is the only FL4 change.

Several further LokSound CVs will be altered to free up buttons 2, 5 and 6 and to separate the motor control adjustment buttons from those used to select light and sound options.

I'll complete the table below when I receive the Howes decoder and I can identify the sound slot numbers.

Howes LokSound Decoder:

TCS FL4 Decoder:

The Windhoff mpv data is now entered into the locomotive listings on Traincontroller and a simple test schedule for a test track video is in place.

To see the demonstration video, click here

The power car LokSound Aux2 Function Output (plus common positive) powers the existing floods.

A series string of 2 LEDs with a common series resistor of 1k can be connected in parallel with the existing Aux2 load, plus a dimmer single LED (+ 4k7 series resistor) on the side of the water tank.

A triple LED + 560R string, a double LED +1k string & a single dimmer water tank LED + 4k7, all wired in parallel, could illuminate the rear car. To avoid the need for a new miniature twin connector between cars, the LokSound Aux 3 can be activated via a new  MOSFET buffer, to carry out the double strobe function, leaving the pink FL4 function lead to power the flood lights in the rear car. (The double strobe wiring will of course have to be modified.)

The new circuit diagram would look something like this:

Right, I've updated the rear car circuit, removing the local common positive and FL4 pink wire feeds to the warning strobe light and substituting connections to the under-floor tracking, which route across the coupler, to the strobe light in the power car. I've also rerouted the FL4 pink wire through a new deck hole (together with a common positive wire) into the rear car water tank, ready to attach the new floodlight LED circuitry.

Next, the power car..... Removing the underside cover, the new wires powering the warning strobes have been soldered to the central pads of the under-floor tracking PCB. A quick check with a bench power supply, confirms that I've got the wires the right way around and both power car and rear car warning strobes operate from these wires.

Adding the new MOSFET:

Gate (=Aux 3) and Source (=GND) connections for the 2N7002 MOSFET.

Very thin enamel covered wire links have been soldered to the GND and Aux 3 points indicated in the photo above. These were then connected to a 2N7002 N-channel MOSFET, glued upside-down to the PCB near the motor connections. Finally, the MOSFET drain is soldered to the warning strobes negative wire, while the strobes positive wire is soldered to a common positive pad on the decoder PCB.

The updated decoder pcb assembly.

The new LEDs have been fitted to the modules and connected in line with the circuit diagram above, to the original spray module lighting supply (using a small strip board glued to the inside of the water tank module).

The power car LokSound V4 now requires the Aux 3 function output configuring to provide a double strobe output when button 6 is pressed:

The rear car FL4 now requires that the pink function wire is changed from a double strobe to a constant output, and that this output is triggered from button 5 instead of button 6.