I have 2, the Aquasearch and the Goldquest SS - they are fantastic machines.
I do not know who might be able to help you with repairs, you may want to send Clive Clynick an email, as he had issues with his. Check out his web site (http://www.clivesgoldpage.com/) for his contact info, he has always been very congenial when I have emailed him.
Good luck!
Charles