The one thing that I do before ever installing a decoder in a DC loco is to run the loco on a DC-powered track. Among other things, that will tell you if the motor is wired correctly for directional travel.
Rich
Alton Junction
If the throttle is set to forward, the headlight comes on, but the loco moves in the opposite direction, the correct fix is the motor polarity by swapping the orange and grey wires as David suggests. If you change NDOT in CV29 it works, but if you forget about that and reset the decoder, you'll be scratching your head wondering why it runs in reverse.
Also, since this is a Proto S2, did you run a new orange wire to the bottom of the motor and isolate the tab that contacts the frame? If not, you have a very high likelihood of frying the decoder if the loco ever derails, since the whole frame is connected tot he lower motor brush and if a sheel is pushed into it, it will connect track power to the motor output resulting in fried decoder. The Proto and Atlas Alco switchers are NOT plug and play even if they do have an 8 pin socket.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
I don't think that reversing the orange and gray wires is going to make a difference in the lighting since the OP says that the motor is functioning well, and he has already tried to CV29 fix. The problem seems to be in the lighting function outputs.
Which of the four DH123 decoders is it? DH123D?
The blue wire is common, white is forward, and yellow is rear. So, the white and blue wires should be operative here.
If all is wired correctly, you could try setting CV61 to 1 instead of 0 (default).
This is what the Digitrax decoder manual has to say about CV61.
Program CV61 to a value of 01 and the decoder will map the normal reverse light function output (yellow) to be controlled by the F4 function key. In addition, the normal forward light function output (white) will bcome a non-directional light output that is controlled by F0 (light function) button on the handheld.
Do what D. Bedard suggested. If that doesn't solve the problem, I would start over.
ENJOY !
Mobilman44
Living in southeast Texas, formerly modeling the "postwar" Santa Fe and Illinois Central
I had a headlight problem when I installed Digitrax decoders in several Kato N scale RDC's. The headlight function was reversed. I reset CV 33 to 0 and 34 to 2.
I am not sure about a DH123, but on my TCS decoders, the blue and white wires power the front headlight; also, if you want front direction only to turn on the light (full, no dimming in reverse), set FOF (CV49 on the TCS) to "0".
Dante
Not sure what's going on. I did what you suggested Martin, and nothing changed. This should be so simple to get right, but I'm at a loss. Ready to tear the whole install out again and start over.
Thanks for the suggestion, it was a good one and should have worked.
Jim
Visit look4trains.com
Jim,
Solder both the white and yellow wires to the light. Doing so won't hurt the decoder and the light will be on in both directions unless you turn off F0.
Martin Myers
Relatively new to hardwired installs, I have done three or four so far. My problem: I installed a Digitrax DH123 in a P2K Alco S2. The motor functions well. I can change the normal direction of travel by writing different values to CV29. However, I only installed a front LED headlight in this unit. No matter what I have tried so far (CV33, 34, 35, CV61) I cannot make the headlight light when the engine is travelling in the direction the light is shining. I have F0F and F0R both set as non-directional, but the light will only light when the engine is travelling away from it. This is true for any value of CV29. Suggestions of what to try next would be welcome!
Thanks, Jim