I am using a borrowed radio mic and can't for the life of me get the thing to work on my A1!
Batteries are fully charged and it's on the right channel,etc.I have the reciever plugged into the mic socket on the handle(there is also an XLR cable too) I put it on my Sony PD-170 and it work straight away....

did you go into the audio menu to switch XLR on??

if you're using the trs-to-miniplug cable on the receiver, make sure the trs end is connected to the receiver and the right-angle miniplug is connected to the camera. make sure xlr is set to "off" in the audio setup menu. note that the receiver is a mono source, and audio will only record on the left channel.

if you're using the trs-to-xlr cable, just make sure xlr is set to "on" in the audio setup menu. phantom power should be off. with the xlr connection, you can choose to record the audio to a single channel, or send the source to both the left and right channels.

Be aware that if you connect a balanced audio source to the mic jack via the 1/8" (3.5 mm) mini-phone jack, you will get equal but out of phase signals on the left and right channels. This can net to effectively zero audio mixed to a mono monitor.