NCE decoders


Just a few notes here:

cv 30 = 2 factory reset





Custom DCC programming for a USAT GP7:

I did a DCC install for my friend Chuck, so I've documented the NCE setup

GP7 #1716 had an AirWire setup and a Phoenix 2K2 in it.

I don't have the Phoenix programmer, so I listed up the Phoenix programming to see what functions were already "taken"

Phoenix programming:

f0 lights
f1 bell
f2 horn
f3 coupler
f4 crossing horn
f5 "working" (prime mover heavier load)
f6 dynamic break (not needed)
f7 sometimes revs up, not reliable
f8 mute

So now on the the NCE D408 programming. I decided that I would separate the upper and lower headlights so I could run them separately, upper headlights as gyralights, and lower headlights just on in the proper direction.

first, connect the outputs:

1 - white - front upper headlight
2 - yellow - rear upper headlight
3 - green - front lower headlight
4 - violet - rear lower headlight


now, program the decoder functions:

  • set output 1 (front upper headlight) to gyralight - cv120 = 17
  • set output 3 (front lower headlight) forward headlight(set to f0 fwd) - cv33 = 5
  • set output 3 (front lower headlight) to solid on in forward - cv122 = 1  


  • set output 2 (rear upper headlight) to gyralight - cv121 = 18
  • set output 4 (rear lower headlight) forward headlight(set to f0 rev) - cv34 = 10
  • set output 3 (rear lower headlight) to solid on in reverse - cv123 = 2


Now I wanted to control the classification lights. As they come from USAT, they are red and green bidirectional. This is really kind of weird, red would be used on the back of a loco if it was running light. Many diesels had a read light of some type on each end to do this, but not usually in the location of classification lights.

In the forward direction, classification lights were unusual on diesels, but if there was anything it would be white, designating an extra. Some railroads considered all freights unscheduled, thus extras. Green signifies not only an extra, but an extra in multiple sections, highly unusual outside of steam locos.

That, combined with the fact the stock USAT LEDs are common cathode, impossible to drive with a DCC decoder where you must use common anode, caused me to get different LEDs, white/red ones, and with only 2 leads, not with a common.

A little searching and thinking came up with a circuit to run these with 2 function outputs, but now which outputs that can be mapped to available functions.

Looking at the NCE documentation, really only the F6 and F7 functions on the NCE make sense.

So, tie the remaining 2 function outputs to F6 and F7:

  • output 8 is the solder pad
  • output 7 is white/green

and program F6 and F7 to control the 2 outputs

  • F6 - solder pad - cv40 = 16
  • F7 - white/green - cv41 = 8




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