How do I get the castle radio working again?

Solution 1:

You should try reassigning the settlers to a different task (food, water etc), remove all power lines and power connections. This is a common bug. Try fast travelling away and back again, as well as restarting your machine.

Just done some research and found this reddit post. More specifically, this comment, which should help you out:

On PC:

Open up console using ~

Select the radio transmitter (click on) (hex value should be 0009FF48[EP]) you can confirm its the right reference by selecting the radio transmitter, typing sv and confirming bAllowPlayerAssignment = False is a listed autoproperty in the Papyrus output (you may have to scroll up to find the autoproperty).

with the radio transmitter selected type: setpapyrusvar bAllowPlayerAssignment True

with the radio transmitter selected type: sv to confirm the variable has been changed

(got to workshop mode) assign any random settler to the radio transmitter, this should force the minute man to sit down and start using it again with the settler you assigned to the transmitter selected, type: setpapyrusvar bWork24Hours True this should make the radio still work at night

Hopefully this helps you.