So, you have just finished a decoder installation and are getting ready for the moment of truth… will the smoke stay in or will you set it free?
Rest assured, everyone has released the smoke for a decoder at least once. It happens. Don’t be intimidated by it. But, there are a few steps you can take along the way to minimize this experience and validate your work.
Before discussing the process, I would like to describe my physical setup. After about the six smoking decoder, I started looking for a better a way. Errors happen. Hidden shorts are, well, hidden. Sometimes you miss things.
The best practice for working with DCC is to set up a test and/or programming track.
What is a test track? Simply put, it is a dedicated track for testing engines separate from your main layout. Do you need one? It just depends. If you have a basement sized layout with hundreds of locos, yes. If you have a 2x4 N-trak module with a couple of locos, probably not.
What is a programming track? Simply put, it is a 100% isolated section of track that is connected to a special set of outputs on the command station to be used for the purpose of programming DCC decoders. Do you need one? Yes, if you plan to use DCC regardless of the size of your layout or the number of locomotives you own.
Almost every DCC Command Station produced today has the ability to establish an isolated programming track. There are two modes you can use to program a decoder, Program On Main (POM) or Program Track. When you use Program On Main mode, you have to specify the address of the decoder you want to program and then the CV you want to change. Every decoder on the track that has that address will be changed accordingly. When you use Program Track mode, only the decoder(s) on the Program Track will be changed. It will be changed regardless of the address or any other CV value. This is particularly important if you have forgotten the address or entered a value that has the board locked up. It is also handy for doing resets and complete reprogramming.
Here is a schematic of how I have wired the test track. I have many additional devices connected to my track at input “A” since I works with many different decoders. The devices include a Soundtraxx PTB-100, a LokProgrammer, a LokTester, a QSI Decoder programmer, and a Digitrax PR3. I will undoubtedly have more as time goes by and new products are introduced.
Subsequently, I use the Digitrax PR3 as my interface to a PC (and JMRI/Decoder Pro) at this connection. This connection is only necessary as you develop a need for the device.