Model Railroading > N Scale Plug n Play Decoder Testing

I've aquired a lot of N Scale over the years, and I know that DCC is the way I want to go on my future layout, but I am extremely frustrated right now and need help.

Since nothing is coming out from manufacturers that I want, I've been buying decoders for my non-equipped locomotives. My DCC system is NCE, so I've been buying primarily NCE decoders.

I did my first install a couple years ago. N scale locomotives aren't rocket science. I installed the decoder, put the motor tabs on the decoder contacts, applied Kapton tape to isolate the tabs from the frame, put it together, placed it on the track to program...and the locomotive was a brick. It would run on DC, but on DCC, the decoder wasn't detected by the system. Re-read the instructions, and could see nowhere that I went astray in the installation. Chalked it up to a bad decoder, but got busy with lie and didn't attempt to install a different one.

Tonight, I'm bored, and decide to do some decoder installs, placing NCE N12A1 decoders into Atlas SD60s. Install the first one...it's a brick. Nothing. Won't even run on DC power. Another bad one? I get a second decoder, and I decide I want to test this one before I install it. I go to my programming track, connect jumpers from the track to the motor tab contacts on the board, and the system can't detect the decoder. Yet another bad one?

So I was wondering if this is an acceptable way to test a decoder? I know they have decoder test kits, but this seems like it should work. I just don't want to send an annoyed email to NCE saying their decoders are crap when in reality my issue is user error.

If you actually connected jumpers from the track to the motor tabs you likely fried the decoder!  The track power should ONLY connect to the track tabs or red & black wires.  The motor MUST be completely isolated from the track and connected only to the motor tabs or orange & gray wires.  Testing before installation is an excellent idea, but to test a decoder you need a motor or resistive load connected to the motor terminals.   There are several decoder testers available, and there have been articles on building you own tester.  Just understand that if you connect track power to the proper tabs (NOT the motor tabs!) your DCC system will still not be able to detect the decoder until you connect a motor to the decoder.

Barry Draper

Well, I definitely won't do that again! Luckily I only tried it with 1 decoder. When I installed that decoder, the locomotive would operate on DC power, but the DCC would not detect the decoder, so I guess it's shot.

Read the decoder warranty at the NCE and Digitrax websites. If you smoke a decoder you can send it back with a reasonable exchange fee and get it replaced or repaired.

If you cannot find someone to help you with a few decoder installs then spend some time with you tube videos. View several as you will find not all of these self produced instructional videos are 100% correct especially when it comes to programming.

Keep in mind the track side or red and black wires are the decoder input. The motor orange and grey wires and lights with blue, white and yellow wires are the output side. Those sides can never be directly connected without damaging the decoder usually fatally.

Posted from iPhone

Well, I found a rather significant problem this morning...I didn't have the DCC power connected to the track! So I guess I didn't cook my decoder.

I installed a 3rd decoder in a different locomotive last night, and was able to program it and run it this morning, so at least I know I am installing them correctly. But the second one still doesn't work, and I'm going to try the first one again.

Here are some photos and instructions on how to install decoders in N Scale locomotives.  I hope it helps. 

http://www.tcsdcc.com/Customer_Content/Installation_Pictures/N_Scale/N_Search/search.html

I've done over 60 installs and I've gotten the "no locomotive detected" message at least a dozen times. Usually it is bad contact either in the pickup strips or of the decoder in the frame. Atlas units with the one piece light board seem to be a problem with he thickness of the decoder. I use TCS mostly and the decoder so are thinner than the stock DC boards so they move around. I read a trick where you put a tiny amount of solder on the pads to make it fit snugly. In the situation of a bad decoder, I try to install it in another locomotive. Also buying another decoder can prove it if you have a roster of locomotives to convert in the future. TCS replaces bad decoders for free. NCE will replace ANY brand decoder for $10. Digitrax has charged me $18 plus shipping when I needed replacement. I stick with TCS because of the excellent service.

Ryan Wilkerson
Fair Oaks, CA

Thanks all for the advice. I'm going to play around with them to see if I can get them to work. The solder thing makes a lot of sense as well.