Graham Farish Chinese Split 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 Chinese-made split-chassis locos, including:

• Class 47 47832 'Tamar' First Great Western 'Fag Packet' livery (371-226)
  Class 47 Guide
• Class 91 91004 'Grantham' GNER Blue (371-801)
  Class 91 Guide
• Class 91 91021 'Archbishop Thomas Cranmer' GNER Blue (371-802)
  Class 91 Guide
• Class 91 91026 'York Minster' GNER Blue (371-800)
  Class 91 Guide
• Class 158 DMU in Northern Rail livery (371-556)
  Class 158 Guide

The conversion requires part of the chassis milling away to isolate the motor from the track power. Depending on the which specific body and chassis variant you have, the top of the chassis block may also need milling so the decoder has somewhere to sit. For more information on our recommended decoder locations, check out the model specific guides above.

Step 1 - Remove body

Remove the body by pulling gently upwards. If there are any underframe parts that will prevent the two halves coming apart, remove those too.

Step 2 - Disassemble

Undo the two screws that are holding the two halves of the chassis together. Take out the plastic pieces that pass through, as well as the two circular spacers and the rectangular spacers.

Take out the two bogies, and the motor.

Step 3 - Mill the chassis

Using a file or Dremmel style tool, remove the indicated metal from each side of the chassis where the motor contacts touch. You can check if you've removed enough material by popping the motor back in temporarily, and using a multimeter to check there is no continuity between the metal of the chassis and the motor contact.

Step 4 - Prepare the track pickups

Using a sharp blade, scrape away the black paint from underneath where the chassis screws and plastic square nut sit.

Step 5 - Reassemble the chassis

Reassemble the chassis by replacing the plastic spacers, motor and bogies. The easiest way to do this, is to place all components into one half of the chassis, and then place the other half directly on top.

Step 6 - Wire up the decoder

Solder the grey and orange (motor) wires from the decoder to the pickups on either side of the motor. Check there is no continuity between these two wires and the chassis.

Strip about 5mm of wire from the end of the red and black (track pickup) wires and tin them with solder. Loosen one of the screws that hold the chassis together, and trap one of the tinned wires against the chassis at either side. Check you now have continuity between the rails/wheels and the red/black wires.

Step 7 - Test

Place the loco on your programming check and check you can read the loco ID and that it responds correctly to commands. The loco should jitter forwards and backwards a few times when reading values from the decoder.

Step 8 - Refit body

If all is well, refit the body. If you find that the body won't completely click back into place, it may be that there isn't quite enough space for the decoder. If that's the case, apart from using a smaller decoder,, you have a few options.

• Mill away a few millimetres from the top surface of the chassis block.
• Relocate the decoder to the underframe battery box
• Locate the decoder inside one of the end cabs

Underframe Battery/Equipment Box

Top of Chassis Block

End Cab

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