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Installing the Atlas DCC Decoder into Atlas/Kato HO Scale Diesels
For many years, Atlas has offered quality HO scale diesel locomotives that contain a unique "solderless wiring harness".  The wiring seems to be a complex mass of plastic and wires.  But it is very simple and easy to disconnect. 
  • A grey plastic platform snaps onto two black plastic tabs that form part of the motor mechanism. 
  • Two bare copper wires run down each side of the grey plastic platform.  These copper wires are held in place under 8 plastic tabs - 4 tabs for each wire. 
  • In the middle of the plastic platform, these copper wires are bent in towards the middle of the platform. 
  • Two copper tabs about 1/8" wide come up from each side of the motor and are bent under the two copper wires at one end of the grey plastic platform. 
  • One grain-of-wheat bulb is located in the middle of the plastic platform and provides light to each end of the locomotive through a clear plastic light tube. 
  • Bare wires from the bulb are bent under the two copper wires. 
  • Four black wires which are attached to the pickup wheels are crimped onto the ends of the two bare wires on the plastic platform. 
An ingenious system that uses no solder! 

Newer Models
The wiring harness for newer models consists of a green printed circuit board that provides directional lighting. 
  • The printed circuit board snaps onto the two black tabs that form part of the motor mechanism. 
  •  Wires from the motor are threaded through holes located on one side of the circuit board.
  •   Four black wires are attached to the pickup wheels from each truck.  Each of these wires is threaded through holes located at each end of the circuit board . 
  • At each end of the circuit board is a grain-of-wheat bulb whose wires are threaded through holes in the end of the circuit board. 
  • All wires are held in place using black plastic snap-on covers. 
Again, an ingenious system that uses no solder! 
And Now an Even Better Locomotive - With DCC

With the introduction of its DCC Dual Mode Decoder, Atlas has taken these fine HO scale locomotives to a new level.  The Atlas 341 Dual Mode Decoder is a premium quality decoder that gets rid of that rats nest of wires and black electrical tape that is so typical of many decoder installs.  The Atlas 341 decoder simply drops into the place of the solderless wire harness - whether it's the old-version grey plastic platform, or the newer green printed circuit board.  It can easily be installed on any HO-scale locomotive that has the two black plastic motor tabs. 
In addition to the usual locomotive control functions, the Atlas 341 supports two additional functions - typically for lighting effects.  Using the Atlas GP-7 as an example, we'll walk you through the steps for installing the decoder.  Then then we'll show you how to install some grain-of-wheat bulbs for simple headlight control. 
A suggestion - before you start installing, print the instructions and read them thoroughly from start to finish. 


Steps for Installing the Atlas Decoder
Installing the Atlas 341 Decoder involves a maximum of 9 simple steps.
  • Removing the old Wiring Hariness
  • Preparing the copper strips from the motor for wiring to the decoder
  • Preparing the pickup wires for wiring to the decoder
  • Preparing a styrene (plastic) spacer to fit between the decoder and the motor.
  • Installing the decoder
  • Determining which end of the locomotive is front and which end is back
  • Connecting the motor wires to the decoder
  • Connecting the pickup wires to the decoder.


Some Words of Wisdom
  • Do not use black electrical tape or double-sided sticky tape. 
  • Only use heat-shrink tubing. 
  • Do not use a 250 watt solder gun!!! - unless you've got a good supply of decoders. 
  • Use a 25-45 watt pencil soldering iron. 
  • Be careful with the soldering iron. 
  • Remove all handrails and other plastic parts that can be removed. 
  • We assume no liability if you follow these instructions!

The Atlas 341 Decoder - Photo copyright Atlas Model Railroad Company.
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