How to convert N Gauge Graham Farish Class 20 to DCC

This guide covers the following models:

• Graham Farish Class 20 in blue livery (8205)
• Graham Farish Class 20 in blue livery (375-026)
• Graham Farish Class 20 in black (late crest) (371-027)
• Graham Farish Class 20 in grey with red stripe (371-028)
• Graham Farish Class 20 in blue livery (371-029)

Step 1 - Remove Body

Unclip the yellow front piece and remove the screw behind it.

Lift off the body. You may want to mark which end of the chassis is the front/rear to make it easier later.

Step 2 - Remove Bogies

Undo the screw at each end of the chassis and remove the bogie retainers. Drop out the bogies and put them aside.

Step 3 - Modify Lower Chassis

Turn the chassis upside down and desolder the capacitor. Solder a black wire to the copper strip where one of the capacitor legs previously was.

Strip another black wire and trap it under one of the screws. This would normally be a red wire, but black will be used here as it can be seen from certain angles.

Move the lower brass arm to one side and remove the spring, brush and brush sleeve. Replace with a digihat. Solder a black wire (normally grey) to the end of the spring. Add shrink sleeving to the brass arm. Replace the brush and spring, and move the insulated arm back into place.

Step 4 - Modify Upper Chassis

Turn the chassis back the right way up. Repeat the above step with this brass arm, again replacing the brass sleeve with a digihat. Solder a black wire to the spring.

Route this wire towards the rear of the loco and then to the centre of the chassis underneath. You should be able to route the wires so that they sit neatly between the pickups and the centre gear. If done correctly, the wires won't touch any moving part and will be hardly noticable once reassembled.

Some kapton tape can be used to hold the wire in place.

Step 5 - Fit Decoder

Solder the four wires to the decoder. Cover the decoder in kapton tape or shrink sleeve to protect it from shorting against the chassis or track.

Position the decoder in the middle of the chassis so it is hidden from view, and fix in place using some black tack or glue.

Refit the bogies.

Step 6 - Refit Body

Refit the body, screw and yellow front piece, and the conversion is complete.