Sorry guys but I'm a complete newb to marine electronics. I'm trying to soak up as much knowledge as I can as fast as I can. Ran into a problem yesterday. I was testing a Gamin 421s that came with my boat. i connected the main multipin cable with the screw on collar, but could not get it disconnected. is there a trick to those collars? The collar doesn't want to unscrew and I was definitely afraid I was going to break something. It didn't help that it was 45 degrees out and my hands were frozen. Any help would be appreciated.