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Help. I have a digitrax super empite builder. I followed the manual on how to select and run a dcc loco. On page 15 it had me put in the default 03, that I did and it worked. along with putting a dc loco on 00. So now I want to program in the dcc loco number of 340. But no luck. I'm not understanding how to put the number in. What am I missing. I need some help or can someone point me to the right page in the manual. I'm new to dcc so this is a learning curve. Loco is p2k sd-9 HO scale. Help:confused:


Milw Road in SW Wisconsin
It depends on your 'throttle' but the basics are in the Digitrax manual. Use either a dedicated 'program' track or get all other engines off of the layout if you are programming the address. With a DT400 series throttle:

o - Push the “Prog” key
o - Make sure “Pg” is displayed in the bottom center of the display
AD2” should be displayed on the left side of the screen
o - If you want a four digit address (128 & above) push the right knob down one time
and “AD4” should appear in place of “AD2
o - Use the keys to select the number you wish to program the loco to (340)
o - Push the “Enter” key followed fairly quickly by the “Y” key
(this changes CV 29 to enable the four digit address for you)
If successful you should see the number you programmed in the display
o - Push the “Exit” key to get out of Program Mode.

* - Note that you have to press the "+" key real fast after the "Enter"
key so that the bit in CV29 flipped to use a 4 digit address.

If you have a 'sound equipped' engine, it is possible that you may need a 'booster', but I have never seen a P2K engine with QSI sound to have a problem. I have had problems with MRC sound decoders in Athearn Genesis models that only can be programmed on the main(My 'Power Pax' booster would not program them on the program track).
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OK, I have the dt400 and I was able to program the loco number in. But now when I turn up the throttle up to 3 the loco takes off like a jack rabbit start. So somehow I think I changed the speed settings. When it was on default it was a nice slow start up. The loco has no sound and it has a dh123p decoder. Not sure were I missed up. I been reading thru the manual and not seeing or understanding how to reset the throttle if thats what needed. Thanks for any help. CF.


Well-Known Member
Try a CV 2 set at 0 and see if the first turn to speed step 1 on your DT400 gets it underway at all. If it won't move at all, try a setting of 10, then 20, then 30, until it just begins to creep along at speed step 1.

NOTE! make sure you are doing this in Ops Mode. Make doubly sure. Hit the programme key three times (I think) to get it to Ops Mode, and then change CV2.


Fleeing from Al
Also, make sure the DC capability of your DCC engine is turned off. This can lead to jack rabbit starts and runaways with some decoders.


Thanks, Selector and UP2CSX, I got it moving and now to work on the lights. slowly I'am trying to understand the manual and get the hang of this. Sorry it took so long to thank you.CF


Well-Known Member
I believe that different decoders have slightly different CV's that control lighting. I believe that one of the most important ones is CV 29. You must get into the decoder manual, not the Digitrax manual, and find out how lighting can be manipulated on your model.

Remember that when it just gets too confounding, or if you feel you have made a huge error, just set the address on the DT400 to "00" and do a full factory reset in Ops mode. Make sure all other engines are off the layout! :eek: Again, your decoder manual tells you how to reset your decoder to factory defaults.


Master Mechanic
With a DH123x decoder, set CV 08 to 08 to reset to factory defaults. I believe this is true for all Digitrax decoders.


Well-Known Member
Also, make sure the DC capability of your DCC engine is turned off. This can lead to jack rabbit starts and runaways with some decoders.

I've had some personal experience with this one, but it's pretty much history now. The old Digitrax DH-121's were notorious for it, and some early QSI systems performed better with DC mode switched off, but we rarely if ever see this one anymore. I have some folks I program for and they run on both DC and DCC depending on where they are in the round robin meeting cycle, or club vs home, whatever, so this option isn't available for everyone :D

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