With DCC one of the great advantages is having realistic sound effects in your locomotives. A lot of the newer locomotives on the market are equipped with sound right out of the box. This leaves our older units a bit lacking, stifled, quiet. This article covers installation of a sound decoder in a Kato AC44-9w that came from the factory without a decoder or room for a speaker.
We do not use any special machine tools however this is considered an advanced level article.
Locomotive Selection
For this project we are installing sound into a KATO CNW C44-9w. This model was not shipped with a provision for sound, newer models have room for a sound decoder and speaker.
Decoder Selection
 (Click for Larger Image) |
We are trying to make this install as easy as possible. Digitrax® manufactures a SoundFX decoder which has both sound and control features. This is in contrast to a decoder that only has control functions without any sound. The decoder is designed to replace the existing board that Kato installed for lighting and the DCC socket. Installing the decoder is quite simple requiring only a screwdriver.
Remove Locomotive Shell
Before pulling the shell off the chassis, remove the handrails from the walkway and side of the locomotive cab. Once the handrails are removed gently squeeze the shell near the center and work it loose carefully.
Board Removal
Use a phillips screwdriver to loosen both screws holding the light board in the locomotive. The second screw is under the DCC plug near the left flywheel. You can remove the plug by rocking it back and forth as you pull up. After the board is removed pull the brass clips holding the motor leads and four wires going to each truck.
Chassis Inspection
Remove the trucks by loosening the motor first and working the worm gear out of the top of the wheel assembly. Remove the plastic covering of the fuel tank by using a flat screwdriver.
Chassis Modification
Cut the chassis to fit the speaker and provide a path for the speaker wires to the DCC decoder.
Speaker Installation
Place the speaker in the fuel tank and feel the speaker wires up through the catwalk.
Decoder Installation
Screw in the decoder and attach the appropriate wires. Be sure to orientate the decoder correctly so the lights (LEDs) fit near the slots but not in the slots for lighting.
Decoder Fully Wired
Shell Before Modification
The picture below is the shell before I made the cut for the speaker wires. I placed the shell on the locomotive and marked the wire hole locations with a pencil. This will be a rough cut and does not need to be exact or pretty.
Shell After Modification
This photo shows the modifications to the shell which will allow the speaker wires to reach the decoder on top of the motor.
Reassembly
Place the shell back on the chassis, pay attention to the speaker wires. You do not want to pinch the wires between the shell and chassis. Leaving the speaker wires loose you should not experience any problem with pinching the wires.
Optional Enhancement
I notice that the speaker picked up metal debris from the layout as the speaker is very close to the track. I cut a protective square out of .15" styrene sheet which is very thin. I use a bit of black electrical tape to attach the shield in front of the speaker. This did not limit the sound capability at all and provided extra protection for the speaker.
Conclusion
You are now ready to program the locomotive and push it into service.
- Mark Goedert
Digitrax and SoundFX are property of Digitrax Inc. All rights reserved.
