Like I had mentioned before, I am new to DCC. I purchased the GP7s because they were both Pennsylvania RR, had different numbers and were on sale. I purchased most of the items before the track was ready to use. I bought the E-Z Command because of the price and it would run the DCC. The cost of other DCC controllers is out of my price range. I had no idea of the differences between the sound and non sound units. I am finding out all of this as I go along. There were no foot notes that stated " Our sound and non sound units run differently and the non sound units hum,this is normal" I didn't find this out until I had sent the the non sound unit, that I thought was defective,back to Bachmann and was told there is nothing wrong with it. Installing a hard wired board is no problem at all, disassembly and soldering in the new board is something I have no problem doing. I have taken a few units apart and cleaned out the excess globs of grease that are shipped with. Just got my Labelle lubrication kit and will be cleaning and re lubing all of my units. Thank you for the JMRI DecoderPro web site. I had taken a quick look and just might be something that would be helpful. I don't know of any local Model RR clubs to help re program my units to run together and would I still be stuck with the hum in the non sound unit?