VR F class by Roco

Updated: Dec 15, 2020

Items used:

ESU 58823 LokSound 5 DCC Micro decoder with Next18 loose wire harness

ESU 50321 11x15mm sugarcube speaker

DCCSound Stay-alive circuit

8 pin plug


Disassembly

The body is first removed from the running boards by removing the radiator grille.

Very little room exists for a decoder, stay-alive and speaker in the model. For reliable running, the model necessitates fitting of a stay-alive circuit to the decoder, to overcome short power interruptions.

Decoder installation

The V5 Micro decoders comes with an 8 pin ribbon cable. Unfortunately the cable does not fit in the cab, so it's swapped out for a Next18 harness with loose wires.

Ribbon cable with 8 pin plug:



Ribbon cable swapped out for 8 loose wires:

The 8-wire harness of the decoder is shortened to be about 30mm long. A spare 8 pin plug was then used so the decoder could be removed in the future if required. The 8 NMRA wires were then soldered to the 8 pin plug.



Stay alive and speaker

The stay alive comprises one, 25V 470 uF capacitor, 1N4007 diode and 100 ohm 0.5W resistor.

The speaker is a 11x15mm Sugarcube style one, and must be so small as to fit in the model. Normally a larger 13x18mm driver would be used, but there just wasn't room in this model.


A small amount of material is used from the cab end window glazing piece to aid re-fitment of the body. The body is then carefully refitted over the finished chassis. Reassembly is completed by refitting the radiator grille molding.