The loco is not dcc ready ,it is a blue box kit , is a sd40-2. if any knows thank you. Chris
Digitrax DH123AT fits in without soldering.
ATHEARN (not atheran) older blue box kits use the frame as a ground, and a fair amount of work is needed to make it DCC. Not the kind of job for a novice. My [2c]
My advice would be to hire an installer locally and ask if you can watch him do his work.
I would bet that if you tried this install, you will blow a decoder.
David B
I don’t think it is hard at all. If you are anywhere near mechanically inclined it should not be a problem. So in a highly unlikely first case scenario he blows a decoder the first time and learns a very valuable lesson that serves him well and saves him a lot of money in the future on other installations. To me its like saying you have a flat tire. You better call somebody who knows what they are doing to change that when the instructions are in the owners manual. There are numerous web sites that explain how to do a Blue Box in detail with pictures. Have at it.
Chris, you be better sereved asking this question in the DCC section. First thing that comes to mind is how much power does the BB draw. Some of the old motors will draw a lot power will eat a decoder even when installed right. Ask me how I know? [:D]
Cuda Ken
The reason I suggested he watched someone do it is as follows as there are 2 ways to do an install into an Athearn BB loco.
The first way is doing the minimum required wiring (Digitrax DH163AT boards). While this will work, it actually doesnt work WELL. If you follow the instructions of the decoder, you dont actually address some of the underlying issues of the Athearn electrical design;
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You are relying on mechanical-electrical connections between one side of the trucks and the frame.
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The frame is live and if you are using metal couplers, you run the risk of a short if you run your locos back to back.
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The motor draws too much amperage overtime.
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The gears tend to gum up over time.
Yes, the install will run, but you will loose electrical contact on a regular basis, have shorts if you run your loco back to back and a mechanism that is hindering the motor.
The second way to do the install is to take the entire loco apart…everything. Here are the steps to a reliable, low-current draw Athearn BB decoder install.
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Take apart everything, down to the gears. Remove the motor so you are looking at a bare frame.
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Place ALL the gears in a tupper ware container (with lid) with soap and water. Shake to clean
So as I understand it the second way has seven steps and produces a very acceptable solution. Hardly rocket science in my opinion and I still say easily done by anyone who wants to give it a try.
No, it isnt rocket science, but rather Athearn science.
I challenge anyone to show me on the Web of another install that mentions my steps. All of the other install instructions fall under my “first” way of doing things.
David B
Check stall speed amps w/meter on straight DC. Get decoder that will handle load. I have 2 athearn locos, F7/9, SW1200. My dad is the eletronics guy I go to for questions. Used DH123 in both.They were hardwired. Make sure motor is isolated from frame. Loco’s are 35+ yrs. old. Those old motors pull alot amps.1 amp is’nt big enough for these old motors. I made the mistake of trying to clean the wheels by spinning on napkin(SW1200).and blew decoder. Stall amps will kill a decoder. Now I only clean wheels (F7/9) by hand. (hate brass wheels). When clean, it runs smooth as silk. Dane
Kalmbach has a good book on DCC, available at your LHS, which has a chapter on installing a decoder in a blue box Athearn with pics etc. Just get the Digitrax harness mentioned above and follow along. ANY decoder that fits the 9 pin harness will work fine. I’d try a TCS one.
Well David, that is the one step I have never done, I have known about it but been to, well lazy.
David, with soldering the wires to the trucks the frame is still hot right? When you do your conversions do you leave frame hot or make them cold? I think part of my problem has been wheels hitting the hot frame while cleaning.
Is the reason to replaces the wheels just because they stay cleaner? I have a Heavy Weight Athearn F-7 I am wanting to take a crack at again. It has nickel wheels all ready.
On the RTR Athearns, would you remove the board and hard wire, if so why?
Your friend Ken
Here is how I wired up a Athearn SD40-2. It was a little newer, had the hex driveline and factory nickel-silver wheels. On the SD40-2 there is room to solder the black wire to the proper part of the truck. The frame is still hot, but I mount the Kadee couplers in an insulated box. To make the frame not hot would take a bit of work, as the pivot bearing area is there as well. If you just added some fiber-plastic shim, the height would be off.
On the newer RTR Athearns, at very least I would take the motor out, and add a layer or two of electrical tape. From the factory they rely on paint to keep things insulated. Some of the boards have been failing, you take your chances. If you decide to hard-wire, remember that Athearn uses 1.5 volt bulbs, so you would have to add resistors somewhere. The Genesis board had LM317T voltage regulators on it for running the lights.
I like the TCS Back-EMF decoders in Athearn engines. Put it on step one, and it starts to move, no adjustments needed.
This discussion about the AT harness is interesting. Over the weekend I fitted decoders to two BB locos. For the first I used an AT harness and found a few problems. The new motor clips fouled the flywheel where the wire is soldered so needed to be reshaped. The wire was soldered so that it left in line with the motor axis rather than out to the side. Most of the wires were too long to get a neat install. In the end I ended up shortening most of the wires and soldering direct to the loco. I used an AT for the second install as well but hard wired, although I did use the motor clips and plastic motor blocks. If I do another BB install I will simply use a plain harness rather than bothering with the AT harness.