The operative word here is "used."  Failure is probably the reason they were sold.  Buyer beware.

It's probably cheaper and easier to just buy a new one that is known to work and has a warranty.

BluNami does the same thing.

All good if you are digitally conversant.

I am not.

Call Soundtraxx.

You're not oversimplifying, you are making it too complex.

EZ command is not able to change any CVs at all or reset anything.  And unless you know the locomotive address, you can't even get into it to reset CV8 without putting it on a program track, which doesn't access the locomotive by address.

Executive summary:  You have to put your locomotive on the program track of some more advanced DCC system or program it on the main of the same system (only if you already know the address, which you don't).  EZ command is basically a DCC train set power source for people who don't care about CVs and stuff like that.

And, hopefully, when you took the decoder out and disconnected the wires , you marked each ones to know where to reconnect.  Especially if you did all eight of them.  If you didn't, "rewiring" will require a back feed of each circuit to identify.

I don't know anything about Arduinos. I'm too old. 😂😂😂😂😂

By a professional

Faulty plug, or power wire?

And every vendor of DCC systems has a starter set. 

I have experience with several systems but this is the Bach Msn's house so it's not really appropriate to talk about other Brands of equipment.  I will say that I started off with a Bachmann EZ  command and used it for a year before I moved a more advanced system which anyone with a serious pursuit of Model Railroading will want to do.  EZ Command is not unlike learning to ride a bicycle with training wheels, it's very simplified and limited but gets the job done.

Even with a basic system like the EZ Command, you'll be astounded at what realism you can achieve with operation and sound.  Good luck in your quest and report back to us how you are doing.

These pre/spectrum engines are rarely worth the work they take to get running when they have complex problems like this one, unless you are a real tinkerer or a longtime skilled Model Railroader.  If you really like the engine, you ought to be able to find a used one pretty cheap on eBay, and keep this one for parts.  I suspect that you can get this engine for less than $75 online auction.  When to get that engine running right would take hours upon hours of time.  Would you rather be running a train?  Or doing what I suspect would end up digging further and further into a bottomless hole as more unforeseen problems arise.

Most of the problems with Model Railroad stuff this old stem from the fact that most of it was made to be toys, they led the rough life of a toy, and don't come out at the end undamaged .  That engine in particular, I bet a kid was pushing it back-and-forth on the floor trying to make the wheels roll and sprung it all catawampus, as we say down here.

Especially if you are an all steam guy like me!

😂😂😂😂😂😂

I hope that the early Missouri Pacific blue and gray wouldn't be too much to ask for. I know that Pennsylvania, New York Central, Union Pacific, and Santa Fe always sell, but it would be nice to get some other roads besides those overcooked ones sometimes.

I don't think any GP7's survived into the Norfolk Southern days to be lettered as such.

 Call Soundtraxx. They have Model railroaders on staff there who will be able to answer any question you have about any of this.

Bachmann had something like that once. Google is your friend.

Aren't those Sanborn maps mega cool.