Originally Posted by Frank
Problem solved. I am blind. I couldn't read the legends on the back of the G68. I had the cables connected from the HD621 to MD1 on the G68 in reverse order.
I shouldn't beat yourself up about this. The legends on the sockets are different on the G68 to the HD621 and it's absolutely not intuitive "plug and play".

Glad you got it sorted.

Malcolm