Dapol Class 66 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 conversion is the same for the following Dapol Class 66 variants:

• Dapol Class 66 66545 in Freightliner green (ND050)
• Dapol Class 66 66713 in GBRf 'Forest City'

The chassis is a two-part split chassis. There is a switch on the bottom of the loco to select between day or night running modes. There is a small PCB on top of the chassis to facilitate this, and a further long, thin lighting PCB on the inside of the body shell. Most of the factory PCBs are not DCC compatible and will be modified or removed completely.

This guide assumes fixing the loco to day running mode, i.e. the headlight on the left is lit and the one on the right is left disconnected. The conversion includes both tail lights on either end, as well as the top central white 'halo' light.

Step 1 - Remove body

Remove the body by gently pulling upwards.

Step 2 - Convert Motor Connections

Desolder the components on top of the motor. Desolder the wires that go from the day/night switch to the small top PCB.

Remove the chassis screws (including the chassis wire tabs) and gently prise apart the two parts of the chassis at one end. The bogie should drop out. Repeat for the other side.

Run your finger along the inside of the underframe and it will unclip. There are two points at either side to unclip - they are easy to identify because you can see the chassis metal pin through the black plastic.

Turn the chassis upside down and remove the capacitor from the bottom of the motor. Remove the day/night switch and the wires attached to it, the other ends of which were desoldered earlier. The day/night switch cannot be used in DCC because the lights at each end of the loco need to be on separate decoder circuits.

Remove the copper contact from around the motor frame. Solder a grey wire to the bottom of the motor, and an orange wire to the top, then put the motor back in the chassis.

Pass the grey wire back up to the top, along the side of the motor in the same route that the switch wires previously used. Clip the two chassis halves back together and re-fit the underframe.

Re-fit the bogies. The easiest method is to line up the driveshaft from the motor with the bogie cardan shaft, and slide them together. Then prise the two chassis halves apart slightly, and push the bogie in at an angle so the locating pin connects. Rotate the bogie so it sits correctly and re-join the two halves. Repeat for both bogies, then put the screws back in. Make sure the copper contacts are not bent out of shape, and reform them if they no longer contact the inside surface of the chassis.

Solder a red and black wire to the two chassis tabs removed earlier, if possible put some heat shrink sleeve over them.

At this point, you will have four wires: grey/orange attached to the motor, and red/black attached to the chassis. You can skip the more complicated lighting conversion steps if you prefer and simply connect these wires to the decoder and you're done for a motor-only conversion.

Step 3 - Modify Main Lighting PCB

Remove the main lighting PCB from the inside of the body. Cut the PCB as shown so that the halo lights still have a handy stub of PCB that we can use later as a soldering point. Desolder all of the wires, making a note of which side of each LED is positive/red or negative/black. The central section can be discarded.

Solder two new wires to each halo LED stub.

Step 4 - Modify Cab Lighting PCBs

It is possible to do this with the PCBs still attached to the body, but they can be removed and re-fitted later if you prefer.

Desolder all of the wires from the back of the cab PCBs. There are three LEDs on each PCB, each with two legs making a total of six legs per cab. Note the copper solder pad that joins two of the LED legs. If you want to connect both white headlights, you will need to cut/scrape away the middle part of the track to break the connection.

Either way, check that there is now zero continuity between any of the LED legs. In this guide, we just want the day running light rather than both headlights lit at the same time, so the right-hand white LED will be simply left disconnected.

Solder wires to the LED legs as shown in the diagram, and connect in the halo wires from earlier. This will achieve the halo plus normal left-hand running lights when going forwards, and both red marker lights when going backwards. You will end up with two lighting negative wires (yellow/white) and one positive common (blue). In the photos, red and black are used for lighting positive common (red) and lighting negative (black) in some places.

We will re-purpose the original day/night switch PCB as a central point for the three lighting wires (yellow, white, blue). Solder the white, yellow and blue connections from your decoder each to one of the three pads. If your decoder does not have a blue, solder a bridge wire from the red track pickup instead (this is the 'half wave' technique). You can just as easily use the black track pickup, it doesn't matter - but red is better as this will be used as the 'lighting common positive'.

Solder a 1kOhm resistor to the pad that has your lighting common positive connected to it, and then solder the lighting common positive wire from the body to the other side. If possible, add heat shrink sleeving around any exposed wire.

Solder the yellow and white negative lighting wires from the body to the yellow and white pads.

Glue or blacktack the halo light stubs back in place. If you removed the cab PCBs, glue or blacktack those back in place too.

Step 4 - Test

Put the loco on your test track and read the loco ID. It should shuffle backwards and forwards, and then return the default loco ID of 3. Turn the lights on the test them, and make sure the white/red lights illuminate correctly according to the direction of travel. If all is well, secure the decoder and wires with some tape, and re-fit the body.

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