Having had a good few issues with our Raymarine RAY 240E, we finally thought that having fitted our repaired units today that we would at last have a functioning fixed radio.
For a sort of dummy-run, I put the box into the console and plugged everything in without screwing it in: although the repaired handset didn't work quite as it should, the brand new one from the second set we have acquired appeared to function perfectly, even retaining our MMSI when switched on and then off again
Having screwed the box back into the fibreglass, I plugged everything back in: appears to work fine, turns on, receives well, still contains MMSI......however....whenever you transmit or just blip the transmit button, the trim tabs turn on! The LEDs on the display do their little warm up thing, and then the closing thing - when the power is cut they normally retract to the raised state -, and even though the tabs are already fully raised the motors whirr for a second or so...very weird. Doesn't appear to do it when their down or even just switched on already but its strange when they do.
Our only two thoughts so far are that something is making an electromagnetic field collapse within the radio when the button is pressed and somehow this causes an issue with the tabs...or... alternatively, when the radio transmits it causes such a drain of current on the battery that the tabs are tricked into thinking that the power has been cut, although it wasn't even on in the first place, and the switch remained off continuously. Bearing in mind that we haven't tested it with a running engine yet, it doesn't seem quite right!
Although I'm doing a GCSE in electronics at the moment, my skills do not go much further than tracing the wires to their origins as I have done, the only interesting end enters a wrap of insulating tape and then emerges as a big thick cable plugged directly into the tabs box in the console. The only places anything related to the radio or tabs meet is at the isolation switch, and the handset cable is cable tied to one of the tab wires at a certain point, although both are heavily insulated.
Any thoughts would be much appreciated, in the short term, leaving the tabs "on" even when not in use would seem the logical option, although most of the time they are left down to a certain extent so not a problem.