Installing a decoder in a HO Kato NW2 : LUSENET : Wiring for DCC : One Thread

Does any one know how to insulate/isolate motor and wheel pickups on a HO Kato NW2 switcher? I want to install an N gage decorder (DN140)in this locomotive.

-- Emund (Ed) Price (, February 24, 1999


I have done this for installing Dynatrol receivers in 4 NW2's in the past, and the same technique should work for installing DCC decoders.

Begin by completely disassembling the chassis, noting carefully the orientation of the motor in its plastic mounting brackets. Notice that the motor picks up power through two phosphor-bronze contacts which rub the two halves of the chassis weight. To isolate the motor, we will cut these two contacts just short enough to hide behind the plastic mounting brackets. Be careful here -- although not impossible, it is a lot easier to shorten the contacts if they are too long than it is to make them longer.

Next, solder a short piece (3"?) of flexible hookup wire to each contact. You can add a piece of heat shrink to the wire and contact if you are bery careful and if the heat shrink tubing is very thin. I generally do not do this, since it can make the chassis halves spread apart. Now move the motor around in the mounting brackets until the wire and contacts are behind the plastic bracket where they cannot contact the chassis.

Before you put the motor back into the chassis halves, we must make a way for the wire to exit the halves and go into the cab where the decoder will be. Gently put one half of the chassis into a vise (I use a "Work Mate" craftsman table). Use a hacksaw to cut a channel about 1/8" deep through the metal chassis half and into the motor cavity, just missing the flywheel cavity towards the cab side. Next cut a channel just above the flywheel cavity, intersecting the first channel and connecting back to the cab area. This should allow the motor to be mounted in the chassis halves with the wires safely placed in the channels and ending in the cab.

So how do you pick up power? Notice the two brass contacts in the cab back wall, which poke down into two channels in the chassis just above the rear truck. Simply solder the decoder pick up wires to these brass contacts. The decoder output wires connect to the wires coming from the motor, of course.

If you want, you can also cut a channel clear through to the forward headlight, and replace the diode with a bulb of your choice. If you don't, the headlight will work with the loco pointed only in one direction, since it is a LED. I have not found a good way to work the cab light. Any bright ideas?

-- Norman Beveridge (, April 11, 1999.

I am now working these NW2's with decoders, and with a little work a cab light is possible.

Begin by carefully removing all the "glass" from the cab. Note the placement and order of all these pieces. Next, remove the plastic bracket which holds the brass pick up clips and also the cab LED light. On top of this bracket is a circuit board. Gently remove the circuit board and brass clips from the plastic bracket, noting its orientation. With small nippers, carefully cut off the resistor and LED. Place the bulb of your choice in the previous location of the LED, and hold it in place with rubber cement, contact cement, tape, or whatever you choose. Feed the lamp wires down through the holes (choose the correct holes!) in the plastic bracket, and then reset the circuit board and brass clips into the bracket. The lamp leads can now be attached to the decoder directly if the solder pads are exposed, or to the appropriate decoder wires if the decoder is "potted" or otherwise protected.

I have also noticed that this plastic bracket provides a convenient place to connect the red and black decoder wires for rail pick up, rather than soldering to the brass clips down in the cab.

I might also add that the new N scale decoders, such as NCE N103, are so small that installation in the NW2 is no problem at all. I still can find no way to keep the cab interior, however. But this is a small price to pay.

-- Norman Beveridge (, April 13, 2000.

I placed the decoder in a different place: I removed some material from the two weights in the area of the tank with a metal-saw. Then I placed the decoder into this space and hide it by the original plastic tank. The wires from the decoder are thin enough to lay in the gap between the two halfes. You don't need a lot of wires, because you can solder the red and black for the rails directly to the bronce-stripe which connects the trucks. The orange and gray are ok with ~4cm to connect to the motor. Only the yellow and the white wire have to be laid to the top of the engine. There is enough space between the two halfes and you can get the wires up between motor and flywheels. You can get the "blue contact" from the LEDs on one of the weights. Drill al little hole and drive in a small screw to have a point where solder can connect.

Greeting s from Carsten Hamburg - Germany

-- Carsten Linow - Germany (, January 04, 2003.

-- Warren C. Gearrick (, January 29, 2003.

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