Graham Farish Class 158 DMU Poole Chassis 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.

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This guide covers the older Poole-made Graham Farish Class 158 diesel multiple units including:

• Class 158 DMU in Northern Spirit Transpennine Express livery (371-525)

This conversion requires a Digihat to isolate the lower motor brush from the chassis.

Step 1 - Remove body

Remove the body by gently pulling upwards.

Step 2 - Modify copper conductor strip

Undo the bogie clips by turning them through 90 degrees. Remove the two screws holding the large copper strip, and the clip holding the brush/spring in. Remove the copper bush, being careful that the spring doesn't fly out and disappear. Using pliers or snips, cut the strip into five sections as shown.

Step 3 - Refit copper strip

Refit the two long pieces of the copper strip and replace the screws. Solder a red wire to bridge these two halves. Solder an orange wire to the piece of copper strip with the hole in it. Replace it, followed by the bush. Make sure the carbon brush and spring are still inside (the brush should go in first).

Solder a black wire between the lower two copper strips that were not removed. Remove the capacitor completely.

Step 4 - Fit digihat

Turn the loco over, and remove the clip holding the other spring/brush inside the copper bush. Remove the copper bush and replace it with a plastic Digihat. Solder a grey wire to the end of the spring. Place the spring back inside the digihat, making sure the carbon brush is still inside.

Put a piece of heat shrink sleeving over the middle of the clip, so that when refitted it cannot make an electrical contact with the spring or wire.

Refit the clip, and pass the grey wire up through the chassis towards the top.

Step 5 - Add track feed wires

Solder a black wire to either of the places where the black link wire meets a copper track. Do the same for a red wire, to either places where the red link wire meets a copper track.

Step 6 - Fit decoder

Route the wires to the underside of the loco and wire the colours to the decoder as follows:

The decoder will sit inside the underfloor accessory box, neatly out of sight. If you prefer, you can install it in the body, however that will require some of the inside roof plastic removing.

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