OpenDec02 DCC Decoder – Users manual

Welcome to the OpenDec02 User Manual!

The OpenDec02 is a high-end, open-source Digital Command Control (DCC) decoder designed specifically for installation in model railroad locomotives. Developed with a commitment to NMRA compliance and versatility, the OpenDec02 offers fantastic performance and customization options for model railroaders of all skill levels.

Purpose and Benefits:

The primary purpose of the OpenDec02 decoder is to enable precise control and operation of model locomotives within a DCC environment. By integrating advanced features and adhering to NMRA standards, the OpenDec02 empowers model railroaders to enhance the realism and functionality of their layouts.

Key Benefits Include:

  • Versatility: Compatible with a wide range of locomotive types and configurations, the OpenDec02 offers flexibility for various modeling applications.
  • Customization: With extensive programmability options, users can tailor the decoder’s behavior to suit their specific needs and preferences.
  • Reliability: Built to withstand the rigors of model railroad operation, the OpenDec02 ensures consistent performance and durability over time.
  • Open-Source: As an open-source project, the OpenDec02 encourages collaboration and innovation within the model railroad community, fostering a spirit of creativity and exploration.

Throughout this manual, you’ll find comprehensive instructions, helpful tips, and valuable insights to assist you in getting the most out of your OpenDec02 decoder. Whether you’re a seasoned model railroader or just starting out, we’re confident that the OpenDec02 will exceed your expectations and elevate your modeling experience to new heights.

Thank you for choosing OpenDec02. Let’s embark on this journey of discovery together!

Getting started

Congratulations on your purchase of the OpenDec02 DCC decoder! This section will guide you through the initial steps to begin using your decoder and integrate it into your model railroad locomotive.

1. System Requirements:

Before proceeding, ensure that you have the following items:

  • A compatible model railroad locomotive.
  • A DCC-compatible command station or controller.
  • Basic soldering tools
  • Access to the OpenDec02 user manual (either digital or printed).

2. Package Contents:

Inspect the contents of the OpenDec02 package to ensure everything is included. Your package should contain:

  • The OpenDec02 DCC decoder module.
  • Documentation, including the user manual and any additional instructions.
  • Any accompanying accessories or components, if applicable.

If any items are missing or damaged, please contact your supplier for assistance.

3. Installation Overview:

Before installing the OpenDec02 decoder, familiarize yourself with the installation process outlined in this user manual. Key steps typically include:

  • Identifying the locomotive’s motor and lighting connections.
  • Removing the locomotive’s shell to access the internal components.
  • Installing the decoder according to the provided instructions, ensuring proper placement and connection.

4. Safety Precautions:

  • Ensure the locomotive is powered off and disconnected from any power source before beginning installation.
  • Handle the decoder and associated components with care to avoid damage.
  • If soldering is required, take appropriate safety measures to protect yourself from burns and fumes.

5. Additional Resources:

Refer to the OpenDec02 user manual for detailed installation instructions, troubleshooting tips, and other valuable information. Additionally, online forums and communities dedicated to model railroading may provide helpful insights and support from fellow enthusiasts.

6. Contact Support:

If you encounter any difficulties during the installation process or have questions about using your OpenDec02 decoder, don’t hesitate to reach out to our customer support team. We’re here to help you get the most out of your decoder and ensure a smooth and enjoyable modeling experience.


This section describes the required steps to install your new decoder into your locomotive. The instructions assume some electronic knowledge and you need to be able to wield a soldering iron but it does not require expert level soldering to succeed.

Materials Needed:

  • OpenDec02 DCC decoder
  • Model railroad locomotive
  • Soldering iron
  • Solder
  • Connection wires in assorted colors. AWG28 – AWG24 is appropriate for this.
  • Wire cutters/strippers
  • A couple of short pieces of heat shrink tubing with ~1mm I.D.
  • A 30mm long piece of heat shrink tubing with 25mm I.D.
  • Small screwdriver (if required by your locomotive)

1. Preparation:

  • Ensure the locomotive is powered off and disconnected from any power source.
  • Gather all necessary tools and materials in a well-lit workspace.

2. Identify Locomotive Components:

  • Remove the locomotive’s shell to access the internal components. Refer to the locomotive’s user manual for instructions on shell removal if needed.
  • Locate the motor and lighting connections inside the locomotive. These are typically labeled or identifiable by color-coding.

3. Prepare the OpenDec02 Decoder:

  • Inspect the OpenDec02 decoder for any visible damage. There are no pins or connectors on the decoder, instead wires need to be soldered directly to connections points on the back of the decoder.
  • If necessary, refer to the OpenDec02 user manual for guidance on decoder setup and configuration.

4. Identify Decoder Connection Points:

Identify the solder points on the OpenDec02 decoder for motor and lighting connections. These are labeled as follows on the OpenDec02 decoder:

Motor pads are labeled A and B on the PCB, A should be connected using a orange wire to the A side (or M1) of the moter and B should have a grey cable connected to the B side (or M2).

Lamp drivers, or rather the high voltage/current drivers are marked with AUX and then a number. AUX0 and AUX1 are normally used for driving the front and rear headlights of a locomotive. It is important to connect these lamps (or LEDs) as shown in the schematic below. Each lamp/LED needs a resistor of its own. Now depending on what lamp is installed in the locomotive it may not need a resistor at all. The job of the resistor is to limit the current through the lamp/LED but some older locomotive uses lamps that are already purposed for the driving voltage. In that case a resistor is not needed. If your head lights are LED lights you always need to resistor to limit the current.

The track signals are noted on the board by a short piece of track. Right track should be connected to the PCB pad closest to the motor connections and the left track on the other pad as shown in the schematic below. NRMA colors are shown in the schematic below.

5. Prepare Wires for Soldering:

  • Cut the wires to the appropriate length for connection to the decoder.
  • Use wire strippers to remove a small amount of insulation from the ends of the wires, exposing the bare conductor.
  • We also recommend pre tinning the wires with a small amount of solder. This will make it easier when attaching the wires later on.

6. Solder Motor Wires:

  • Heat the soldering iron and apply a small amount of solder to the tip.
  • Touch the soldering iron to the motor connection point on the decoder to heat it.
  • Place the stripped end of the motor wire against the heated solder point and apply solder to create a secure connection. Be careful not to apply too much solder.
  • Repeat this process for each motor wire, ensuring they are securely soldered to the appropriate motor connection points on the decoder.

7. Solder Lighting Wires:

  • Follow the same process as above to solder the lighting wires to the appropriate connection points on the decoder labeled AUX0 – AUX1.
  • Do not forget the current limiting resistors. Make sure you also isolated the resistors and resistor legs using heat shrink tubing to ensure short circuits can’t happen.

8. Secure the Decoder:

  • Before securing the decoder into the locomotive we recommend wrapping the entire decoded in heat shrink wrapping. This will effectively protect the decoder from short circuits if your loco uses metal parts in the construction.
  • Carefully position the decoder inside the locomotive, ensuring that it does not interfere with any moving parts.
  • Use double-sided tape or small adhesive pads to secure the decoder in place, if necessary.

9. Test the Installation:

  • Before completely reassembling the locomotive completely you should test the installation to make sure that everything works as expected.
  • Reassemble the locomotive, ensuring all wires are routed neatly and do not interfere with moving parts.
  • Reconnect the locomotive to the DCC system and power it on.
  • Test the locomotive’s operation to ensure both motor and lighting functions are working correctly.
  • The OpenDec02 decoder starts by default to listen on the short address 3.

10. Troubleshooting:

  • If the locomotive does not respond as expected, double-check all connections and solder joints for any loose or faulty connections.
  • Refer to the OpenDec02 user manual or contact customer support for further assistance if needed.

11. Enjoy Your Upgraded Locomotive:

  • Once the installation is complete and tested successfully, you can now enjoy the enhanced functionality of your model railroad locomotive with the OpenDec02 DCC decoder installed.