Graham Farish Class 90 DCC Conversion

Mistakes may damage your locomotive, controller or other accessories. Use a multimeter to make absolutely sure you have completely isolated the motor from the track before testing. Always use the Programming Track for testing. Our guides are provided for reference only, and you proceed entirely at your own risk. Unsure about something - try our DCC Conversion Service instead.

This guide covers the older Graham Farish split-chassis models, which use the same brass bushes as used in the older steam locomotives. Similarly to the steam locos, the brass bushes need isolating from the metal chassis. This is done using two plastic digihats, one for each side of the chassis.

Examples of models that require this method include Class 90 electric locos manufacturerd in the mid nineties, including:

• Class 90 90022 'Freight Connection' Railfreight Distribution Grey (8828)

For the newer Chinese split chassis models, for example 90046 (371-777) in Freightliner Green/Yellow, follow the standard Chinese Split Chassis Conversion Method.

Step 1 - Remove Body

Carefully unclip the body and pull upwards to remove it.

Step 2 - Replace brass bushes

One one side of the loco, remove the metal clip ensuring the spring doesn't fly out. Remove the spring and the carbon brush, then take out the brass bush. Replace with a plastic digihat. Repeat for the other side.

Step 3 - Fit decoder wires

Solder a red wire to the side of one of the removed metal clips, and a black wire to the other one. These will provide the decoder with power from the track. Solder an orange wire to one of the removed springs, and a grey wire to the other one.

Place some heat shrink over the middle part of the clip so that there will be no electrical connection between the clip and the spring. Replace the carbon brush and spring, and secure by placing the clip back over the top so that the red/black wire is at the bottom. Repeat for the other side.

Step 4 - Fit decoder

Route the wires up and across the top of the chassis block. There is space to fit a small decoder at each end. Secure using tape, and ensure it is completely insulated from the chassis.

Step 5 - Refit body

Refit the body, and test!

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