
Last Updated: 28 May 2025
Graham Farish Class 91 DCC Sound Installation
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.
Buy Graham Farish Class 411 DCC Sound Conversion
This guide shows how to install DCC sound into the Graham Farish Class 91 Poole-made models, by installing two digihats, a Next18 decoder socket, and a speaker. Models covered include:
The Graham Farish Class 91 GNER model was made in China and has a different chassis arrangement. Please contact us if you are interested in having this model converted to DCC sound.
Step 1 - Fit Digihats
First, follow our Graham Farish Class 91 digihat conversion to install two digihats, one at the top and one at the bottom of the chassis. You will end up with the motor brushes isolated from the chassis, and a grey and orange wire ready to connect to the decoder socket.
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Step 2 - Prepare Chassis
Drill two small holes into the plastic at each side, as close to the metal as possible. These will allow us to pass wires up into the body from the decoder socket installed under the floor.
Step 3 - Install Next18 Socket
Turn the loco over and glue a Next18 socket just next to where the digihat was installed. Solder black, red, white, yellow, blue and two brown wires to the socket PCB. Pass all but the black and red wires up through the holes drilled in the previous step. Also pass the wire from the lower motor brush up into the body.
Step 4 - Connect Track Pickups
Tin the end of the black wire and trap it under one of the large screws. This will provide one of the track pickups to the decoder.
Solder the red wire to the copper strip to provide the other track pickup.
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Step 5 - Connect Motor
Solder the orange and grey wires from the motor to the decoder socket.
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Step 6 - Fit Speaker
Using a Dremmel or similar tool, cut the end off one of the chassis end pieces as shown.
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Refit the bogies and reassemble the chassis.
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Glue the speaker to chassis and solder the two brown wires to it.
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Step 7 - Fit Lighting Socket
We will be retrofitting directional LEDs into the body at a later date. This optional step installs a socket to make it easier to separate the body from the chassis, as the lighting wires can simply be unclipped. With suitable decoder programming, you can alternatively use this wiring for cab lights.
Solder the blue (common), white and yellow wires to a mini socket, and glue it to the side of the chassis.
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Step 8 - Refit Body
Refit the body and the DCC sound conversion of your N Gauge Class 91 model is complete.
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