Roco 4178B Install of a DCCconcepts Decoder

Roco HO 4178B Re 4/4
Installation of a DCCconcepts Decoder

This locomotive has a centrally mounted motor, carden-shaft driven bogies at both ends with power pickups on 8 wheels.
The best method to disassemble the locomotive is to turn it upside down.



Move the body outwards from the middle and the tabs will release, lift the body upwards.



Remove the weights over the bogies, the power pick-up wires from the board and the retaining screws.



An ideal place for the decoder is under the end of the PCB board near the motor terminals and above the carden shaft.

Light from the two lamps is transmitted down light pipes to the front and rear of the loco. Each lamp will be replaced with a Warm White and Red SMD LED.

Remove all components from the PCB.


A few modifications to the PCB board.




Cut the PCB tracks to isolate the switch from the circuit and also the supply for the lights.

The blue wire supplying positive voltage from the decoder will be soldered to the lower track.

Below - SMD LEDs soldered in place a small piece of black card placed between the White and Red and glued in place with CA.







To fit the decoder wires in above the motor weight- grind a hollow in the bottom of the PCB board.

Mill out material from the weight that fits over the motor, leaving enough room for the wires to fit under the PCB.



Groove milled in the weight to accommodate the decoder wiring.



Mill out material from the end weight to accommodate the decoder, make sure there are no sharp edges, to wear away the decoder casing.




Close view of the decoder under the PCB

	Lighting is on four functions Before the body goes on test the locomotive on the Programming track to make sure the decoder will read. If there are any short circuits in the wiring, the system will report a short without damaging the decoder. Also, test the loco for operation on the track before putting the body back on.