Atlas 4 function decoder problem

Model Railroader Electronics and DCC
1

I am trying to put accessory lights on my atlas SD 35. The locomotive comes with an onboard 4 function decoder. I tested outputs C and D with light bulbs to see if the work. Function D makes the bulb light with 13.65 volts. When I test function C I read 13.65 volts on my meter. but as soon as I connect the light the voltage drops to 0. Also the function always seems to be on when F1 is off. When I press F1 it turns the function off, Output D works fine though, when I press f2 the light comes on. I’ve never worked with an Atlas decoder before so I have no idea why this is happening. Thank you for any help!

2

This sounds like something that can be corrected through programming of CVs.

Atlas doesn’t make decoders; it was made by Lenz of Germany of possibly TCS or NCE. Atlas’ web site is no help at all because they don’t show that decoder as being in stock and there is no documentation offered for it.

If you can find a part number on the decoder that can be traced to the manufacturer of it, you may be able to find programming instructions if none came with the decoder.

The Atlas decoder documentation that comes with their models is pretty worthless from what I have seen, but sometimes there is a manufacturer’s identity on the decoder.

3

Thanks. The only information I can find on it is that it is DCC PCB #342. I guess I’m stuck…

4

Maybe ill just try a new decoder and take the other one out

5

Traintown:

You can try reading CV 8. If it’s an NMRA compliant decoder this CV gives the manufacturer’s ID number and you can find the manufacturer from the table included here: http://www.nmra.org/standards/DCC/mfgnumbers.html.

Joe

6

Although I have several Atlas locos, I’m not familiar with the SD35. Does it come with with the dual-mode, four function decoder?

If so, does this diagram help?

How about this documentation?

7

Joe.

Most of the DCC on board decoders will have the locomotives manufacture ID. If Atlas put the decoder in it it will come up with 127 in CV8. I have read CV8 in BLI locomotives with QSI decoders in as 38. On early QSI decoders the code would change to the QSI code with an upgrade chip change. Just about all of the on board decoders are a custom deal between loco manufactures and decoder makers. Aftermarket decoders will always have the decoder manufactures code.

Pete

8

Pete:

Thanks for the clarification.

Joe