Minitrix Steam Loco Conversion Method

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 is a general guide to converting many Minitrix steam locos, including examples with a front light.

Step 1 - Remove Body

Remove the body from the loco by removing the screw in the top. Remove the tender body by removing the screw from the bottom.

Step 2 - Remove existing wiring

Desolder the green wire from the tender PCB. This is connected to a track pickup via the copper coil at one end and the motor at the other. Desolder the connection to the motor too. This wire can now be completely removed.

Desolder the black wire from the motor. This is the other track pickup.

Desolder the blue wire from the blue wire from the tab coming up through the middle of the chassis. Remove the 10Ohm resistor.

Step 3 - Remove motor connection

Desolder the copper tab that connects the bottom motor tab to the chassis. This can usually be done without removing the motor. If it proves stubborn, remove the motor by undoing the two screws at the back, it then just pushes out.

Step 4 - Remove bulb wiring

If the loco has a light at the front, desolder the white wire from the tab coming up through the middle of the chassis.

Step 5 - Test

At this point, the motor should be completely isolated. Using a multimeter, check there is continuity between the top rail (with the loco facing left), the wheels on the loco on that side, and the wheels on the tender on the same side. Check there is no continuity between these points and any of the wheels on the other side, and the bottom rail.

Check there is continuity between the top rail, and the tab coming up through the chassis that the blue wire was removed from. Also check continuity between the top rail and the blue wire (that isn't connected to anything currently). There should be no continuity to any part of the chassis, nor either of the two motor connection points.

Now check continuity between the bottom rail, the loco chassis, the tender chassis and the black wire that isn't connected to anything. There should be no continuity to either of the two motor connection points.

Step 6 - Prepare the decoder

Prepare the decoder by removing any wire tails that aren't going to be used to save space. For Lenz Silver Mini+, keep the red/black/grey/orange, and also white if the loco has a light.

Create a small shelf using cardboard, or piece of thin plastic. The chip will need to fit at an angle over the worm cog. There are other places it will fit, even using a bit of blue tack to secure it will work. Make sure it is insulated so there is no chance of a short, and also make sure it cannot foul the worm.

Step 7 - Connect the decoder

Solder the motor wires (orange and grey) from the decoder to the motor.

Solder the black wire from the decoder to the solder point on the chassis upright Add a short extension to the black cable coming from the tender, and solder that to the chassis upright too.

Solder the red wire from the decoder to the tab that comes up through the chassis. Also solder the blue wire from the tender to this.

Step 8 - Test

At this point, put the loco on your test track and try reading the decoder ID. If all is well, you will get the customary jitter and the default loco ID 3 back. Try running the loco backwards and forwards to confirm all is well.

Step 9 - Finish Up

Add some tape if you want, to secure the wires and neaten the job up. Put the loco and tender bodies back on, and you're done!

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