11 - NO - Guide 1 stays steady red, Set and Go flashes red at the same time. Buttons don't change or do anything else.
12 - Same things happens
This flashing of "Set" and "Go" indicate that the communications between the HC and/or AUx port are broken!
In "other words" the connector between the small input circuit board of the Merlin ( "HC", AUX", RJ connectors) is "physically" disconnected from the main control board.
Big chances that the Main Merlin control board isn't faulty !!!!.
The best way is to dismantle the Merlin just to check if the connectors cables are still well connected and not loose !
For dismantling the Merlin, you should first remove the battery cover and the batteries, then the 4 screws under the Merlin Base and at the end the 2 screws retaining the vertical plastic cover (the 2 screws can be accessed in front of the Merlin (black part) just under the crown.
Thanks for all the input. I have just been through everything I can testing this theory.
I have tested the cable with a multitester and all is well. I have examined the circuit board for dry solder joints and all is well there too (I know they could be hidden so I resoldered them just in case.
I have to say that I think the power is getting to all devices ie: HC, TC , BT but the communication is not there.
This still suggests to me that all of the devices are functioning (especially because I CAN communicate with the TC from PC via USB) and it is the Merlin unit communication (motherboard) module that has the problem.
I am going to contact the company in Melbourne and purchase a new unit and then I can try all accessories and see the fault is with the Merlin.
I can even change the motherboard I guess to confirm.