Athearn decoder install - tidy?

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I've got two Athearn locos I've hard wired Digitrax decoder in, a blue box GP38-2 and an RTR GP35. Run great on the test track. The problem I'm having is determining where to locate the decoder and wires so that nothing interferes with the mechanism. I tried mounting the decoder to the shell under the rear fans, but it hits the rear truck. There's not enough room on top of the motor, and if I mount it towards the front of the loco it's visible from the cab. And as far as the wiring, I'll probably tape them to the top of the motor, but since I haven't figured out where the decoder is going I've held off.

The GP35 I think has enough room for the decoder to be mounted on top of the motor, the GP38-2 has a weight in the dynamic brake area that limits the amount of room. Should I perhaps remove that weight and the associated plastic?

Just wondering how others have handled these installs...pics would be great!

Thanks in advance.

Steve W
 

kjd

Go make something!
Here is how I did a GP38-2 and F45. I bend a piece of brass strip and screw it to the frame to make a little shelf to put the decoder on. I only have lights in the front of the GP38-2 because it is one of a pair that always goes together.

I write the date I finished the locos in the shell and the F45, MRL 391, is 10 years old this month. I am in the process of changing the fans and putting in an NCE decoder so I can have the strobe operate.
NCE because for less than the comprable 2 function Digitrax, you get a mappable 4 function decoder.
 

kjd

Go make something!
To get an idea of how much room is inside a locomotive you can use Photoshop or any photo manipulation software that allows layers.
Step 1. Take a photo with the shell on.
Step 2. Without moving the camera and setting the locomotive exactly where it was for the first photo, take a photo with the shell off.
Step 3. Combine them setting the opacity of the shell on photo to less than 100% so you can 'see' the drive inside. I consider the shells to be .080" thick so you don't have quite all that room.

And in the case of the GP38-2 it has that lower section under the DB. Measure from where the shell sits on the frame to the bottom of the bump then measure up from the frame to see how much room there is.
 
Last edited by a moderator:

Smoke

Southern Railway lives on
To get an idea of how much room is inside a locomotive you can use Photoshop or any photo manipulation software that allows layers.
Step 1. Take a photo with the shell on.
Step 2. Without moving the camera and setting the locomotive exactly where it was for the first photo, take a photo with the shell off.
Step 3. Combine them setting the opacity of the shell on photo to less than 100% so you can 'see' the drive inside. I consider the shells to be .080" thick so you don't have quite all that room.

And in the case of the GP38-2 it has that lower section under the DB. Measure from where the shell sits on the frame to the bottom of the bump then measure up from the frame to see how much room there is.
You look at the picture and without reading the directions it's like am I seeing things or is the shell disappearing. I really like the idea though and I think I will try that.

-Smoke
 

davidmbedard

DCC Sound Guru
One could use some not so thin styrene and make yourself a shelf that extends over the flywheels and the motor....then place the decoder on that...the wires will then be held up by the styrene (or make grooves in the plastic to hold the wires in place).

David
 

Rick Stoneman

New Member
I use perf board so you can thread the wires through in just the right places. I cut it into three pieces and glue them off-set and set the center one on the motor with the other two sticking front and back. They sit just below the top so it gives lots of room for decoder and wires. Sometimes I solder connectors on the lights in case they need to be changed.
 

GatorDave

Railroading Fan~Gator Fan
Steve,
I had a similar problem and I found an easy fix. But you will have to forget about Digitrax. Their decoders are too large for Athearn Geeps... there is simply not enough room in the shell. I installed one and the shell would never completely snap down on the chassis.... no matter where I moved the decoder.

Okay, brace yourself! I bought the newer MRC decoder. I know, "MRC does not make a good decoder". I've heard that so many times and I believe their sound decoders (the standard, not the Brilliance) leave a lot to be desired. But their motor decoders work just fine. I have had one installed in a P2K GP9 for a year and it still performs as well as any of the Digitrax decoders I have installed.

I never got to install it in the Athearn Geep because I decided to change eras and the GP38-2 didn't fit my plans. but I did "dry fit" it and the shell snapped on without any noticeable issues. The decoder is tiny.

I don't know if this will solve your problem, but I hope it helps. Good luck, Dave

HPIM0416.jpg


Here are the specifics...

MRC 1650
5-FUNCTION DECODER
with MRC Light Effects
Built-in NMRA DCC plug
Thank you for purchasing our highly advanced DCC locomotive
decoder. Combined with any DCC System, our decoder will
make your model railroad more realistic and more exciting.
• Designed for HO scale
• Built-in NMRA DCC plug
• Maximum current: 1.5 Amp
• Programmable for either 2-digit (1-127) or
4-digit (1-9999) addresses
• Programmable start voltage
• Programmable acceleration rate
• Programmable deceleration rate
• Programmable speed curve (factory pre-set)
• Programmable top voltage
• Programmable 14, 28, or 128 speed steps
• Directional lighting at 0.1 amp rate
• Easy setting “Rule 17” lighting, ditch, strobe and
Mars lights
• 4 accessory functions (F1 to F4), at 0.1 amp rate
• Supports advanced consisting, (CV19)
• Supports programming on main
• Compatible with NMRA DCC standard
• Complies with the Part 15 of FCC
• 23.5mm long x 12.3mm wide x 4.5mm high
 

kjd

Go make something!
Everything I have bought from MRC has been back to them at least once. I have two Tech II 1400s that have both been back twice. They are however the best analog controllers around. I also bought a Sheer Brilliance decoder for a project for someone else. It is misnamed as far as I am concerned, the Brilliance part anyway. It has been back to them twice already because its accessory light functions don't work. The sound is loud but not anything special as far as I could tell. Its light functions leave a lot to be desired, they can not be set up to be protoypical. The decoders don't even look good, with stuff on the board crooked.
As far as fitting Digitrax into Athearn GPs, they fit fine if they are not on top of the motor but back in the radiator area or toward the front in the electrical cabinet area. I prefer NCE lately because of the extra functions for the same price as the Digitrax. NCE is also mappable while Digitrax is only sorta.
 
Steve,
I had a similar problem and I found an easy fix. But you will have to forget about Digitrax. Their decoders are too large for Athearn Geeps...
Good thought Dave, I have gotten in such a routine with Digitrax I never even thought about a smaller decoder. I do have a Lenz that is similar in size to the MRC you used, I'll tinker with it. Thanks!

It's that "step" in the dynamic brake area that makes it difficult. I just installed an ESU Loksound decoder in an Athearn RTR GP35, and the decoder, which is similar in size to a Digitrax, fit just fine on top of the motor. Mounted the speaker in the rear of the shell facing downward and I was all set!

Thanks to all who have replied.
 

I'm a HO'er

New Member
I took the weight out of my Athearn GP40-2 under the non dynamic housing, it was a tiny little weight real tiny. I know the step you are talking about. I modified mine and installed a soundtraxx DSD-AT100LC 1st gen sound/motor decoder. I have alot more pictures if you want to use them to help you out


Now before someone says you can't take the weights out and pull I do agree 100%. This weight is no doubt 4% of the total weight, not worth fussing over IMHO. Here is a photo comparison
 
Thanks for sharing, that's exactly what I was planning on doing, that tiny bit of weight can't make much of a difference. Especially on my "flatlands" layout!
 

RexHea

RAIL BENDER
Steve, another thing that is often overlooked is that you can install an N scale decoder in HO. Just make sure the current rating is high enough. I run an NCE N scale in my P2k S1.
 




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