Garter Carriage adaptor not working

I have two Brother garter carriages (a KG95 and a KG93) and the power adaptor/sensor has stopped working on both of them following yarn tangles. The sensors cut in on both of them to stop the G-Carriage (as it should) but neither will start. I am now looking to buy one or two replacements. Do you know where I might be able to buy one?
Many thanks, Elizabeth