[CA] [CA11] Quantum Radome stopped working - 'failed self test' - what to test?

[Cmonster]

Our Quantum radar has been installed for just over 2 years. It has been lightly used. On our last passage it had been working normally. I put it into standby. Later that night I switched to transmit - and it stated 'Radar Quantum Radome (-60366) Not available. Scanner failed self test'
I cycled the power. No improvement.


It is connected by data cable, so I tried to connect to the radome by wifi from the Lighthouse MFD - connection appeared to be successful and the transmit button became available, but on pressing transmit, it returns same message, failed self test.

To be sure I connected our second Lighthouse MFD by wifi, and the result is the same.
Have tried on another day after a full power recycle. No improvement.

Supply voltage at the switch is normal (24V).
I assume that power to the radome is fine because it's trying to self test.
Does this suggest an internal fault with the scanner?
Are there any further tests I can perform?
Of course I am cruising - not easy to find a Raymarine expert. I have an electronics background.