RTR Athearn Units & Decoders


Alcomotive

Alcomotive

Grandson of an ALCO Builder
Guys I need a little pointing into the right direction....:eek:

I have the following units and want to bring them into service (still new in the box as of now):

ATH8000 - EMD SD40-2 Union Pacific "United Way" #3300

ATH8002 - EMD SD40-2 Union Pacific "Desert Victory" #3593

Will I be able to use the simple DH123AT Digitrax decoder? I have not taken the shell off the chassis yet. Wondered if it had a PC board or not?


Any help or suggestions are welcomed!

THX
Alco out!
 
I don't see why not. Both of those are part of the Athearn RTR line and I don't think they have PCB boards but I may be wrong. One of the ways to tell is if is still has the crew frying headlight. If that's the case, the 123AT is just what you need.
 
Yup you are right! I wonder if I could put in a PCB board of if it would be worth the time?
 
Alco, it's really not worth the time. You can use double sided tape to stick the 123AT decoder and then wire it up. Now would be the time to replace the existing headlight bulb and copper contact strip and add LED's to the front and rear since the 123AT can control headlights in both directions.
 
If the RTR Athearn says DCC Quick-Plug Equipped, then you just take off the DC adapter plug and plug on the 9-pin decoder. DO NOT pluf the piece with the wires that comes with the decoder into the decoder itself. The piece with the wires is an 8 pin adapter. The Athearn PC board has an 8 pin port, but you'll have to solder it according to the instructions (which is impossible)

If it has the bonfire light in the cab then it is probably not DCC ready, and you'll need to solder wires to components to convert it to DCC. If you don't like soldering, get the DH123AT which requires less soldering as some components snap on to your locomotive.
 
diburning is correct - the best decoder fit depends on the vintage of your Athearn. The -AT boards are designed to go in classic Athearn locos that have no DCC prep in them at all. You could put one in a newer RTR unit, but if you do have the RTR, you already have a 9-pin socket and you can use any 9-pin decoder such as the Digitrax DH123, DH163, TCS T1, or NCE D13SRJ. Much quicker and you'll have lights too.

One caveat about the Athearns with 9-pin sockets: before you install the decoder, pull the motor out and make sure the wire soldered to the bottom motor strap is not touching the frame! This doesn't affect DC operation, but it will turn decoders into smoke units. Black tape will effectively isolate it. This has been an on-and-off problem with the RTR units for several years. I hadn't had one with the the problem in a while, then a week ago I got out a brand new SD40, and... shorted. If you have an older Athearn and use the -AT type decoder, you'll need to wire up to the bottom strap and also make sure it's insulated from the frame.

Andy
 
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