G'day all..
I ended up pulling apart the adapter and found a wire had snapped apart.
A
warning for anyone who has the
Canon 350D 12v power adaptor from http://centralds.net/en/ : The unit does not have strain relief on the camera end of the converter box (the end going to the camera). It has some on the other end. I must have pulled mine a bit hard sometime and it snapped a solder join inside the converter box on the cable.
All fixed now, re-soldered.
Roger.