Basically, I’ve been toying with converting to DCC for a little while now. The problem is, I have two locos that I absolutely love (one was “inherited” as well), but they are strictly DC- old enough before DCC ready was common. Is there a safe way to install decoders in these? If it helps, I believe both of the locos are Athearn. Thanks in advance.
Athearns are very, very easy to convert. There several ways and different decoders avaible to re-wire with a little solder work. I also belive Digitraxx even offer a “clip-on” decoder where it is design to work with the older athearns and no soldering at all.
I wouldnt call old Athearn BB locos ‘easy’ to convert. In fact, there are some modifications that are a MUST to avoid issues down the road.
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You need to isolate that motor from the frame. Remove the motor, then carefully remove the bottom clip (watch out for the little spring…) and nip off the 2 feeler contacts. Solder a wire to the underside of the clip and reinstall the clip. On the frame under the motor, place some electrical tape to eliminate any chance of electrical contact.
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You need to make the frame NEUTRAL. This is achieved by removing the trucks and then dremeling off the contact on the truck that contacts the frame (hard to explain but easy to see when you do this). Solder a wire to the remainder of this contact and also solder a wire to the other contact (the one that contacts the long metal clip that delivers electricity to the top of the motor). Using styrene, replace the thickness of the metal that was removed to the underside of the frame that the truck sits on.
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Reinstall the trucks, motor and wire up to a DCC decoder.
With this method, you will be able to run the Athearns back to back with metal couplers (something not possible before).
David B
First off, thank you both for the advice. I just have one question regarding your post, davidmbedard. You mention soldering wires to certain parts of the frame and motor. I’m assuming I need to solder the other end somewhere?
David, I have never had to make the frame nuetral in the manner you describe. On some of the Athearn unit I have, it’s very labor intensive to do what what you describe. There are plastic shank couplers available from Kadee that will prevent shorts between mu’d units. I just isolate the motor from the frame, solder a wire to the clip on the underside of the motor and solder another wire to the base of the headlight clip. These wires become the negative (-) for the decoder. The wire on the headlight clip connects to the decoders - input and the wire on the bottom of the moter connects to the decoders - motor output. From there I cut the ends off the strap that clips to the top of the motor so that there’s only 1 inch on each end. The + motor output connects here. I solder a jumper wire from the + contact (the thing that sticks up from the truck) on the front truck and solder the other end of the wire to the rear truck, leaving enough slack so the trucks can move easily. The + input of the decoder connects to this jumper wire. Lights can be installed as the user wishes. I connect my lights so they are powered directly from the trucks. I’ve done several BB Athearn’s in this way and haven’t had a problem yet.
Digitrax also offers two decoders that make installation in an Athearn a snap. The DH123AT and the DH163AT. These just clip on.
That is the difference between you and me Jeff. You look for the simplest way to achieve what you want, I on the other hand have to please clients with my work. If I were to do what you have described, then have a client install standard metal Kadee couplers…well, lets say that I would be out of a job.
I stand by what I have posted. And the method I have described will eliminate ALL issues with Athearn BB locomotives.
David B
You will need to follow the directions that come with the decoder.
David B
I think you could look at the difference another way. Jeff knows he’s not going to put a metal coupler on, so he knows that frame is not going to be an issue. When you do an install for a customer, you don’t know what he’s going to do with it in the future, so you have to do the more robust installation. But it seems to me that both are right, in the right circumstance. Actually, you said it yourself, Jeff looks for the simplest way to achieve what he wants. Since he gets what he wants, it is the right way for him. You do you installs in the simplest way that achieves what you want. (I don’t think you make work for yourself that doesn’t serve a pupose). Because you are doing the installs professionally, your objectives are different.
It would help if we knew how old the engines are, what kind of engines they are and who made them. I’ve got an old Athearn F7 that is probably 50 years old. I put a decoder into it. I did isolate the motor, but could not make the frame neutral because of the way the trucks transfer power up from the tracks. I used Kadee’s plastic draft gear boxes to isolate the couplers.
That’s the good news. The bad news is that I tried to convert a number of other old engines to DCC, and this was the only success I had. The others all ran poorly even on DC, after 40 years in a box in various basements and attics. So, test number 1 will always be, “How well does it run on DC?”
I, too, have “beloved” old engines. That’s why I invested so much time into trying to upgrade them to DCC. In the end, though, I had 2 old GP-9’s with Kadee couplers, but they didn’t run well enough to put them in service. Yes, I looked into replacing the motors and wheelsets to bring the guts of these engines up to modern standards, but then I found GP-9’s for $40 each, new in the box P2K’s, at M.B. Klein. (www.modeltrainstuff.com if you want to look.) I bought one, put in a decoder, and went out and bought another. They run beautifully, and the detail level is so much better than the old engines.
I did take the guts out of a couple of my old locos, and I now run them once in a while as dummy “honorary” engines along with the new Geeps. At least I got some value out of the couplers I put in.
When I decided to make my new layout DCC, the plan was to convert most of my old fleet. I figured I would save a lot of money that way. It was a good plan. But I ran across a lot of issues. First of all, the layout uses code 83, which older Rivarossi engines don’t like because of their large flanges. Most of my diesels were Athearns and the problems have been well documented by others in this thread. Then there was the issue of the couplers on the Athearn F7s. The coupler housing was poorly designed and I never did learn how to remedy that problem so that was another issue. Gradually I came to realize it was simpler in the long run to just renew my fleet, a few at a time. I began with DCC ready locos and when factory installed decoders and sound became more common, that is what I bought. I know not everyone can afford to do that, so converting old locos might be there best option. But for my money, the newer locos look better, sound better, and run better so the old fleet has been mothballed. I got my money’s worth out of them so I don’t feel too bad about it.
PS I am still kicking myself for buying a small fleet of Athearn BB F7s when Trainworld had a blow out sale on them. This was before I realized how much work would be involved to convert them to DCC.
In response to MisterBeasley, the first engine is a GP7 that I bought in '02 or '03. The second is an F7A of unknown age, but I’d put it at 1980’s to early 90’s. The GP7 is for sure Athearn (still have the box for some reason) and the other I can’t be certain, but I’m pretty sure it’s also Athearn. Also, looking at both of the motors, they’re suspended a little above the frame by a piece of plastic. I’m assuming this isn’t what you mean by isolating the motor?
Also, I use only plastic couplers and don’t intend to ever run consists until I have a much larger layout a decade or so from now.
There are two prongs on the bottom clip of the motor that make contact with the frame. These must be removed. Put a strip of electrical tape in the bottom of the motor well to insure that the motor can’t make eletrical contact with the frame.
Thanks to everybody for the input. I think I’m going to go with the drop-in decoders- I’m not comfortable enough with my skills yet to go changing things inside my locos too drastically.
Check with your LHS if you’re going to buy the decoder there, and if they do installations themselves. They will probably be willing to show you what you need to do to isolate the motor, and any other quirks of the engines you’re upgrading. Bring the engine in with you when you go decoder shopping. My LHS is that way.
You’ve got relatively new engines. They should work just fine. Take a look at the headlights, too. If possible, swap the incandescent bulbs for LEDs. In either case, you’ll probably need to add resistors between the decoder and the bulbs. I use 1K resistors for my LED headlights. Radio $hack has those. Really overpriced, but convenient. They come in a 5-pack for a buck.
The motor must be electrically isolated from the frame in any case, no matter what type of decoder is used.
Lionel Strang’s “DCC Made Easy” book uses an Athearn loco as the example in the chapter on doing a ‘hardwire’ installation of a decoder, using the Digitrax Athearn decoder harness. If you follow along with the book, it’s quite easy to do.
There was a rather extensive pictorial item on these forums a couple of months ago on how to install a decoder into Athearn blue box engines. That post is probably several pages back by now, but it might be worth your time to search for it.
Here’s one I found by searching for Athearn decoder installs:
I saw this on youtube and thought it might be helpful to some out there: http://www.youtube.com/watch?v=YZku8qp0BBs. If someone already referenced this video, sorry for the repeat.
That’s the one I was about to link to. I have it in my YouTube favorites and I also downloaded it to my data drive.
Thanks so much for that post- it really helped to be able to actually see what you guys were talking about.
Hello Wikious,
I would encourage you to try converting an engine. The no-solder kits should work for you and have instructions which should make the process relatively clear. Here’s a link to a switcher I did:
http://www.tcsdcc.com/decoderpics/athearn_sw1500/athearn_sw1500.htm
It was tricky because there was very little room for the decoder. I also did a GP38 engine, where I mounted a larger decoder onto the upper motor clip with foam tape. That engine had lots more options due to it’s size.
These engines run fine on DCC. They are noisey using DC, and that won’t get any better in DCC, but DCC will even let you tweak some performance parameters to smooth their speed control out a bit. I will say, though, that they will never be as nice as a Proto 2000 or Atlas engine. It will be a GREAT learning experience. Don’t be afraid to learn to solder, and remember: you can always get frustrated, put the loco aside for a day or two, rip it all out, and make it way better on the next try. I like soldering in the decoders, and there have been lots of threads discussing soldering.
If we can help further, just ask! 
Jim