VR DRC by Trainbuilder

Updated: Dec 11, 2020

Update 2019

DRC 41 was in the workshops for a new LokSound V5 sound decoder installation and total re-wiring. This particular installation featured the following:

1) ESU 58429 LokSound V5 21-MTC decoder

2) ESU 51967 Adapter board

3) ESU 54671 PowerPack Mini

4) Twin DCCSound speakers, custom designed for the Trainbuilder DRC.

5) TCS 1411 6-pin 2x3 micro connector

6) Rewiring using ESU 51942 black wire.

7) Hollywood Foundry Bullant pick-ups (discontinued).

The DRC prototype was fitted with Cummins prime movers that provided a deep, bassy sound. Hence well designed speakers were required to faithfully reproduce the sound in 1/87. Two speakers, one at end end, featuring 13x18mm drivers were designed for the available space. However neither speaker is visible from outside the model so the effect was successful.

3D printed custom speakers, using 13x18mm drivers wired in parallel:

Deconstructed main chassis showing passenger compartment and speakers to be fitted:

The #2 end speaker was designed to support the ESU 21-pin adapter board and decoder. The purpose of the board is that the decoder can be easily removed from the model in the future, if the need was to arise.

The rear pickups were replaced with a custom 3D printed part that held Hollywood Foundry etched brass pickups in place. These provided better electrical pickup than the factory parts.

Following rewiring of the chassis, the passenger compartment assembly was refitted. To enhance the quality of the power system, an ESU PowerPack was fitted. However it would not fit in the available space due to interference with the body. So, the capacitor was wired separate from the PCB and "thrown over the wall". Neither parts were visible once the model was assembled. The LokSound V5 CVs that address the Powerpack are a little different from those in LokSound V4 decoders.

Charge amount: CV113 = 64 (0...255)

Enable charge: CV31=16, CV32=0, CV339=31

Once the chassis wiring was complete, a bench test presented no issues with short circuits, so work proceeded with wiring up the lights.

To enable separation of the exterior body from the chassis, TCS connectors were used. All up, 8 connections were required for full independent light control:

6 pin connector:

1) Yellow: #1 headlight (F0f), Pin #8

2) Orange: #2 headlight (F0r), Pin #7

3) Red: #1 white markers (Aux 1), Pin #15

4) Black: #2 white markers (Aux 2), Pin #14

5) Grey: #1 end red markers (Aux 6), Decoder solder pad (powered, not logic)

6) Blue: #2 end red markers (Aux 7), Pin #4

2 pin connector:

7) Orange: Interior lighting (Aux 5), Decoder solder pad (powered, not logic)

8) Red: Common positive, Pin #16

470 ohm resistors were placed on the negative side of all LEDs. All joints had heatshrink applied and the finished body was as follows:

Next the model was reassembled and the couplers refitted.

Original installation:

The DRC body is removed from the chassis via six small screws under the floor. To keep the passenger compartment free, an ESU LokSound V4.0 decoder and 16x25 mm speaker was installed in the guard's compartment. The speaker is sealed air tight to the enclosure and the resultant sound level is appropriate.

The lighting has been daisy-chained such the headlights, white markers and opposite end red markers are directionally illuminated with F0. 470 ohm resistors are on each function output (-ve). The interior lighting strip is wired to Aux 1, which is activated via F11.

Front and rear pickups are isolated from the motor, and the motors grey and orange wires are direct soldered to the respective wires on the decoder. Finally the body is reassembled to the chassis and the DRC is ready for service, with authentic sounds from DRC 40.


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