CV list for Bachmann 36-567a Next18 decoder

[Nigelcliffe]

1 hour ago, rogerzilla said:

In that case it must be faulty, as CV8=8 should reset it but all it does is make CV8=108!

Have you tried the CV7 issue I mentioned above ?     It could explain some of the readings you are getting, but not all of them.   
I don't know the priority of commands, but if a pseudoprogramming offset in CV7 applies before a command to CV8 (and I think it may apply first), then your setting of CV8 is actually setting some other CV....
 

Not promising this is a fix, but the list of options are starting to look small - return as faulty (but to who? and you won't get a replacement) or chuck away.  

 

 

[WIMorrison]

If it is a Zimo decoder, you can return through either the supplier that you purchased from (preferred option) or through Rail Exclusive - though you may be without the decoder for a considerable period of time, especially given that components are not available to make new decoders, let alone fix broken decoders.