Available Items

Service Advisory Repair Kit
Proto-Sound 3.0 Equipped O Scale Chapelon 2-3-1 Pacific and Proto-Sound 3.0 Equipped O Scale Class 241A Steam Locomotives

Hi-Rail and Scale Wheel Proto-Sound 3.0 equipped O Scale Chapelon 2-3-1 Pacific and Proto-Sound 3.0 equipped O Scale Class 2-4-1A steam locomotives require installation of this Service Advisory Repair Kit due to a missing component on the Proto-Sound 3.0 circuit board. In the absence of this component, communication between the locomotive tender and locomotive boiler will eventually become permanently interrupted and long term damage to the circuit board in the tender will result.

The missing component is a 470 ohm 1/4 watt resistor that needs to be installed in series with the blue wire that terminates at the 6 pin connector as identified in the instructions below.

Please review the following instructions prior to starting the installation. If you are unable to perform the installation, contact your dealer, an M.T.H. Service Center, or M.T.H. whichever is closer.

For a list of Service Centers in your area, please click HERE or contact M.T.H. Service by emailing service@mth-railking.com.


ESD safe work environment
Phillips head screwdriver
Wire cutter/stripper
Soldering iron with a fine point
Remove the Tender Shell

1. Using a soft surface or an engine cradle, turn the tender over so the trucks are facing up. Locate and remove the 4 screws in the corners and remove the tender shell.
Cut/Prepare the Blue Wire

1. Locate the blue wire on the 6 pin connector. Cut the wire about 1-2 inches from the connector. Strip the insulation from the wire leaving ¼” of wire exposed.
2. Slide the shrink tubing over the end of the blue wire as shown in the picture below. Apply solder to the bare wire to tin the wires. NOTE: Be careful to not let solder drop onto the circuit board. Protect the board as needed.
Solder in the Resistor

1. Trim the legs of the resistor to 1/4” (6-8 mm).
2. Solder the resistor ends to the wires. Clean any flux residue as necessary.
3. Slide the shrink tubing over the resistor and exposed wire. Heat the shrink tubing so it shrinks down around the resistor and wires and does not slide. This will protect the solder joints.
Replace the Tender Shell

1. Reinstall the tender body shell being careful not to pinch any wires.

To download these instructions in English, French and German, click HERE.