Adding DCC to Athearn BB/RTR
- Thread starter fiend540
- Start date
Cjcrescent
Master Mechanic
Depending on how new the RTR's are, they may be DCC ready. If not Digitrax makes a harness for easy installation into Athearn diesels that are not DCC ready. Their DH123AT and DH163AT decoders come with the "no solder" harnesses. If you already have the decoders with different harnesses, then all you will need to get are just the harnesses, the DHAT. These harnesses will fit many other decoders as well, not just Digitrax. Go here to read about them:
http://www.digitrax.com/menu_mobiledecoders.php
There's a nice picture series of what to do from our own Jeffrey Wimbley at http://kcsrailfan.proboards.com/index.cgi?board=dcc&action=display&thread=96. He's converting an F unit but the method is the same for any BB engine. The most important thing is to check the motor with a meter for continuity once you believe it's isolated. Your meter should read zero if the motor is isolated. Any other reading (usually negative ohms) means the motor is not isolated from the frame. No matter who well you do the rest of the wiring, you'll get magic smoke and a blown decoder if the motor isn't truly isolated.
diburning
AlcoHaulic
Caveat: the red wire on the DHAT harness comes with two clips that clip onto the truck brackets for power pickup. The clips may not stay secure on the trucks. I've had to solder the clips to the brackets to get them to stay (which defeats the purpose of not soldering in the first place).
meanjean
Member
Take a look here.
http://www.tcsdcc.com/Customer_Content/Installation_Pictures/HO_Scale/HO_Search/search.html
Some good pictures
http://www.tcsdcc.com/Customer_Content/Installation_Pictures/HO_Scale/HO_Search/search.html
Some good pictures
DCCinstalled
Member
I have attempted to use the harness a few times. I have found it to be just as easy to solder the decoder in without it as the wires will often break off of the clips It is very easy to add LED's while your in there too. Miniatronics Surface Mount Yeloglo LEDs work well and they come with resistors in the pack. Remember heat shrink tubing is your friend when it comes to soldering the LED's to the decoder wires.
Yeah my LHS talked me out of one as he said the clips stink and I pretty much agreed when I looked at the thing. I picked up a NCE decoder with a harness and for now I think I am going to leave the lights unhooked until I can figure out which bulbs to use and if I am going to install ditch lights. I am assuming that the loco will run fine with those wires from the harness that are for lights just capped of with some electrical tape correct?
DCCinstalled
Member
As long as the extra wires are out of the way of the drive shafts you should be fine.
Quick question guys, i was going to follow this link here http://www.tcsdcc.com/Customer_Cont...s/HO_Scale/Athearn/GP38-2/Athearn_GP38-2.html
because they make it pretty straight forward but I noticed they eliminate the rear truck pickup clip. I am just wondering if this is OK to do or if I should run a jumper between the two pickup clips for added security.
because they make it pretty straight forward but I noticed they eliminate the rear truck pickup clip. I am just wondering if this is OK to do or if I should run a jumper between the two pickup clips for added security.
Wouldn't have a picture of where you soldered to on the trucks do you? Is it basically the same spot as where the clip attaches to the truck, bit on the opposite side?
Final question guys, typically what size wire are the leads on most decoders? My wire stripper was too large and I want to make sure I get one that will work for sure.
A little update guys, I decided to solder a decoder/harness into my rtr gp38-2 tonight and following that guide plus your guys advice has led to a successful installation. I am super pumped about this and while i still need to figure out what I am going to do for the headlight at least she lives! Thanks again guys, I finally got to use my NCE powercab!
Good work, Cory. The first one is always the most intimidating. As for the headlights. I used 3mm LED's for both the front and rear. Just solder a dropping resistor in line with the LED's unless the decoder already has 1.5 volt outputs. The Athearn shell doesn't have a lot of clearance for the LED's, especially in the front. I use a 20 degree output LED so all the light is directed forward and none lights up the cab. I use thin brass strips for the headlights, soldering them to the outputs and making a 90 degree bend as close to the decoder as possible. I then cut the strips so the legs of the LED will be as close to the headlight lenses as possible and solder the LED legs to the strips. They are stiff enough to hold the LED's in position and you can take the shell off without worrying about ripping out the headlights.
As for the headlights. I used 3mm LED's for both the front and rear. Just solder a dropping resistor in line with the LED's unless the decoder already has 1.5 volt outputs. The Athearn shell doesn't have a lot of clearance for the LED's, especially in the front. I use a 20 degree output LED so all the light is directed forward and none lights up the cab. I use thin brass strips for the headlights, soldering them to the outputs and making a 90 degree bend as close to the decoder as possible. I then cut the strips so the legs of the LED will be as close to the headlight lenses as possible and solder the LED legs to the strips. They are stiff enough to hold the LED's in position and you can take the shell off without worrying about ripping out the headlights.