While using an NEC Powercab to operate a Bachmann loco wth ESU LokSound decoder I inadvertently ALSO connected the track to a 15v AC current (don't ask). I wondered why operation was rather hesitant, so then compounded matters by changing the 15v AC connection to 12v DC (still connected to the NEC). At this point response from the loco was minimum, unsurprisingly, and I realised my mistake(s).
I have tried resetting CV8 to 8 - sometimes that seems to work, and I get some response from the loco - some of the sounds and just a brief commencement of moving before cutting out again.
Have I damaged it irretrievably? I'm a newbie to DCC (obviously!)