A few weeks ago I purchased a Proto 2000 F7 A & B combo with DCC from a not-so-local hobby shop. I finally tried to run it the other day and while the A unit works fine, the B unit doesn't. F6 will start up the sound, after which the throttle will rev up/rev down the engine sound, but the unit won't move. It's as if it is in "disconnect" stage. F9, which should control the 3 stages (disconnect, standby and shut down) honks the horn; does nothing else. I have to take the unit off the track to turn it off. F2 also honks the horn, as it should. F1 rings the bell; the other "Fs" appear to do their thing. I tried a hard reset (several times) and, while the voice said "reset," it didn't correct the problem. Also tried the unit on straight DC and while it produces engine sound, it won't move. (My ancient DC power pack has "issues" and I couldn't fully check the other functions the unit is supposed to be able to do on straight DC.) Anyone have suggestions as to what is wrong? Bad decoder? Incorrect wiring? I'm a real novice at this sort of thing and wouldn't recognize the latter.