Athearn SP GP40X LM-3S Install

[Espeelark]

I only recently got a RailPro system and did my first decoder install (of any kind)! I started with a "DCC Ready" Athearn Southern Pacific GP40X. I had to cut down the weight over the rear truck so as to allow the iPhone speaker to fit. I also cut a trench/slot in the side of that same weight for the motor's power pick-up wire from the rear truck. It originally went through the center of the weight which required you to disconnect the wire from the PC board if you wanted to removed the weight. This mod will allow the weight to be removed in the future without having to disconnect the power pick-up wire from the PC board.  After that it was at simple matter of soldering the wires to the speaker and then routing/taping the wires in place. I made no effort to replace the head lights (with LED) at this time, or, try to separate the bulbs so that I could install the s'ware for SP's typical gyralights - that will come sometime in the future. Pretty happy with my first effort! 

[G8B4Life]

Looks good.

The commutator indicates that it appears that model has had a lot of use (very black stripe on it from the motor brushes). If so that carbon buildup on the commutator may impact the models performance a bit.

- Tim

[Espeelark]

Thanks for that observation.
I picked up that GP40X used, so, I shouldn't be surprised by that....
What's the best method to clean/restore that?

[G8B4Life]

The best method is simply tied to your confidence level.

You could try a couple of ways of cleaning it; trying to clean it in-place or going the whole hog service.

For cleaning in-place you can try a hard pencil (not ink) eraser or cotton bud (you guys call them Q-Tips) soaked with Isopropyl Alcohol, or both. Lay the chassis on it's side with the commutator end of it pointing towards to the workbench (so the other end is pointing up) and clean the commutator while turning the motor by the flywheels. You don't want any eraser bit's to get into the motor and foul it so that's why to try and orientate the chassis with the commutator end pointing down towards the workbench.

The whole hog method can be seen here: https://model-railroad-hobbyist.com/node/30210#comment-286822, which I suggest reading anyway even if you want to try cleaning in-place.

Be careful no matter which method you choose, you don't want to damage the motor winding's where they attach to the commutator.

- Tim

[Espeelark]

Thanks for the link to your "whole hog" method. I'll see how well it runs (or doesn't) and go from there.
Paul Mac
Modeling the SP in Ohio

[CPRail]

Hi Paul,

I have the quartet of SP GP40Xs on my bench to do. I've noticed that the board that comes with the loco doesn't appear to have enough connections to seperate the lights for the full-meal deal SP lighting. I'm looking at using the Athearn board that comes with the Genesis locos instead, but it requires more wiring as there is no top motor strap on the bottom of the board as on the factory setup.

I like the idea of the slot for the rear truck wire.

I'm using Scale Sound Systems speakers which replace the rear weight, so I'll have to see what JT designed for that wire.

Your install looks good! Glad to know the RP module fits under the hood. I've often gotten everything hooked up and taped down, just to find out you need 1/16" more of room!!

[Espeelark]

Hi Ian - I'll be interested to see what you eventually do with your GP40X quartet as I have one more to do myself.
W/respect to needing 1/16' more room, that happened here as well the first time around. What I found is that the 8 pin connector (?) soldered to PC board that comes with the loco doesn't allow the LM module to sit down low enough. I couldn't talk myself into trying to de-solder that connector, or, cutting it off somehow, so I simply bent the LM leads over on themselves as is visible in the photo.

[ON28]

Good job, always good to learn from other installs.