Author Topic: KEY Challenger decoder install  (Read 490 times)

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KEY Challenger decoder install
« on: August 23, 2014, 04:31:15 PM »
I have posted threads, in the past, asking for help and suggestion regarding decoder install in my brass Challenger and more specifically how to add power pick ups to the brass tender. I gave up on that idea and purchased a complete, sans decoder, Athearn N scale Challenger tender with all wheels including the front truck picking up power. Should be plenty of power to run the Challenger. However when i plugged the tender mounted decoder into the boiler wire harness I had a direct short that shut down my Powercab instantly. I have piddled with it for 2-3 weeks and find that the mistake was 100% mine and I feel real stupid admitting it, so I am going to post some images and story that may keep someone else from repeating my goofiness.

Obviously, the tender wiring was 100% OK, so I shall not cover it. The problem was with the original factory wiring on the chassis. This Key Challenger was made somewhere around 1984 or '85 and I purchased it in 1998, second, third, or fourth hand, who knows. It ran flawlessly, KATO smooth, on analog but when I added decoders all heck broke loose.

Last night, I completely dismantled it and found a couple of things:

1) After removing the plate from the bottom of the first engine, I found that one of the bearing blocks was not installed correctly. After turning it to slip down where         it belonged the axle straightened out and the plate fit as it should. I don't know how it ran smoothly at all, but it did.

2) The wiring was my problem. The right side drivers on the front engine pick up power from the right side rail and carries the power through the gear tower and then onto a set of wipers on the tower. On the second engine, the left side drivers pick up from left rail and carries through the gear tower and wiper. There was a red wire, that I assumed was from the right rail and there was a blue wire that I assumed was black pick up from left rail. WRONG, the red wire was actually picking up from the second engine and left rail and the blue wire was connected to the front engine and right side rail. SO, when I plugged that improperly wired harness plug into the tender plug, I had a direct short. How stupid on my part.

Here is the chassis before attempting first decoder install, you can see the blue wire................

Here are the parts. Note the brass pieces with the wires soldered to them. The wipers, which are the shiny little plates, ride in a groove on the gear tower and screw onto the top of the brass plates that are insulated on the bottom. Not many sub-assemblies to build this nice loco.

Here is an image of the front engine. You can see a groove in the gear tower just above the screw head. The shiny little plates ride in the groove and become not only a retaining device to hold the engine in place but also they become the wipers for power. Pretty slick, I think, and work much better than wipers used by other manufacturers back in the "80's.

I am going to solder new red and black wires to the wiper plates and clean the gears well before reassembly.

Hope this has some value to somebody.

Carl Sowell
El Paso, Texas
Southern New Mexico N Scalers, Las Cruces, New Mexico