Icom 423 cutting out with Command Mike

[ozsailer]

Hello all,
I have a 12 month old Icom M423 and finally got around installing a command mike at the helm which is a factory extra. When I connected it all and turned the power on the main radio came up with a display that said it was undergoing a firmware upgrade which I take was programmed into the new command mike.
All appeared in working order untill I go to transmit and both units turn off when I depress the transmit button. I disconnected the new cable for the command Mike but my main radio is still turning off when I hit the transmit button, Being a Saturday I am unable to get hold of anyone at Icom.
Has anyone had a similar issue and if so how did you resolve it. The main cable between the command mike and the main vhf is one calbe with connections from the factory.
Any help would be of great assistance.

Greg H
Sunshine