This is my situation; I am in the research and planning stages of an HO layout. I do have track on a 4x8 just to run some trains. I have some rolling stock, track, turnouts, and couple loco’s; and my most recent purchase the digitrax zephyr. I plan on doing steam era but along the way a acquired an sd40-2 (stupid impulse buy).
My prob is this, the athearn r2r sd40-2 that i have came dcc ready so when i bought my system i asked the hobby shop owner what decoder i need for it so he sent me home with the DH123D decoder. I plugged it in the locomotive and it will go forward & backward but the headlight is on all the time. Now is this the way the headlight will always work or can something be done or is the loco just not wired for the headlight function? I have been reading the digitrax manual to figure it out but it seems overwhelming at first and when it comes to loco wiring and circuit boards i have not a clue. I have figured out how to change loco addresses and acceleration settings and have tried resetting the decoder, but this has just stumped me.
I must say though my Trix mikado wow!!! With the dcc on its impressive.
The FL (forward light) function key turns headlights on and off. On some DCC systems, the number zero does the same thing. I don’t have a Digitrax system, so I’m not familiar with how they mark their keys, so if there is no FL key, press the 0 key and see if that turns the headlight off.
Thats the problem. The light stays steady even when i try to shut it off with the corresponding function key. The light comes on when i power the track up and stays on.
The decoder’s default values should have been set for directional lighting with FL used to turn the lights on and off.
Try programming the value of 00 into CVs 49 and 50. These are the two CVs that control lighting effects for the headlight and backup light, and 00 in these two CVs set them to normal directional lighting that can be turned on and off with FL.
If you hard wired this decoder, make sure you have the color coding correct – blue wire to both lights, white to the headlight, and yellow to the backup light.
You got that right, lil’ buddy! It’s smoooooooth!..
“Skipper”
P.S. The one thing I would change on the Trix Mikado is the “orange” LED headlight. They should have put in a golden-white one. Trust you got a good price on it.
I tried what u said but the 00 was programed already into cv’s 49 & 50. The loco came with the plug n play deal so no hard wiring was needed and sadly it has no back up light which is cheap in my opinion.
I have a Digitrax system. The F0 function button should control the front head light.
I also have several Athern SD40-2. In my Athern SD40-2 the head light is not isolated through the decoder but gets its power directly from the track. If your light is being powered by the decoder the white and blue decoder wires should be connected to the head light. If you have a single light bulb in the front of the locomotive with a metal clip attached to the frame your light is not connected to your decoder. You can replace the light with a bulb or LED connected through your decoder. You can download the Digitrax decoder manual from the Digitrax web site and it will instruct you how to add new lights to your locomotive.
Maybe the actual problem is that the Athearn RTR SD40-2’s are not DCC-ready. The only RTR’s that are DCC-ready are the ones that use the old RPP shells, and that doesn’t include the SD40-2. Are you sure it isn’t a “non-dash-two” SD40?
Well the loco i have says right on the box sd40-2 and it has the extended rear porch so im sure its an sd40-2. I think Jim is right because it has a single light connected to a metal clip on the front of the loco. What a rotten deal it comes with the quick plug and u still got to rewire the darn thing.
All the Athearn DCC-ready, RTR’s that I’m aware of have wired bulbs (front and rear) and don’t use the metal clip for the bulb. Also, don’t forget that half of the -2’s increased length is in the long hood, so the increase in the porches isn’t very much as compared to the SD40’s.
What’s the Athearn stock number on the box, and the loco’s road name and number?
For comparison, here’s a link to an Athearn SD40 that is DCC-ready. Notice the second, eighth, and tenth bullets describing this loco, all of which are absent from the one you listed: Based on Rail Power tooling with many upgrades Equipped with Quick Plug DCC technology Directional headlights http://www.athearn.com/Products/Default.aspx?ProdID=ATH93561
Now let’s look at the decoders. For the DCC-Ready Athearns, the DH123D is a good choice. Since it plugs right in, you’re not paying for a lot of extra harness or anything else unnecessary: http://www.digitrax.com/prd_mobdec_dh123d.php
For the non-DCC ready Athearns, Digitrax makes the DH123AT which has a wiring harness cobbled together. You still have to do some minor surgery to isolate the brushes and front light, etc, but other than that it’s pretty simple to install: http://www.digitrax.com/prd_mobdec_dh123at.php
My guess, based on the info you’ve provided, is that you got a non-DCC Athearn and the DH123AT. If that’s the case, follow the instructions carefully when it comes to the front light. One side of the bulb should get power through the frame, and the other
So apparently even though the box says it has a dcc quick plug equipped and it does, the loco doesn’t have the features and just able to run on dcc. Here is a pic with the decoder dh123d installed.
HO RTR SD40-2, UP/We Will Deliver #3654 Key Features Fully assembled and ready to operate Factory installed Celcon handrails Next-generation drive mechanism with hex drive lines All wheel drive and electrical pick up Machined RP25 profile metal wheels Magnetically operated knuckle couplers no mention of quick plug I’ve never seen one like this, looks like an aftermarket cobbled up add on, that somebody threw together. anyway, the wire from the copper strip behind the bulb need to go to one of the center terminals on the front of the board. hard to tell from pic, but looks like it 's connected to outer tab which would bypass the board, and the light will stay on all the time.
You are correct the wire coming from the copper tab is connected to the outside terminal on the board. I tried connecting the wire to either one of the center terminals on the board but no success the light still remains on.
I also believe though, that Athearn’s DCC-Ready locos use 1.5v bulbs like the Genesis locos have, and not 14v bulbs like the BB locos.
If that’s the case, connecting to one of the center terminals on the board will power the light through the surface-mount resistor on the board. While that will dim the bulb somewhat, my bigger concern would be that the 14v bulb draws too much current for that SMT resistor to dissipate. That could be a problem.
And as far as the light staying on even when it’s connected to the center light terminals, if this really is an aftermarket cobbled up add on (and it sure looks like it), no telling what else might have been modified to make it “work”.
Let me inform u that when connected to the center terminal on the board the light dims considerably.
I bought it at a LHS and the loco wiring looks like a professional install, what would you recommend? Maybe i should give athearn a call and see what they say.
Could you please tell me a good reference book or books so I can learn and better understand loco wiring myself?
If its any consolation, the Atlas AEM7/ALP42 models come DCC Ready and PnP for a TCS decoder. I installed it and it has no control for the number boards, they are always on with track power too. Not sure if the mfgs just don’t realize they’re doing this or they just don’t care.
