popping noise when switching tv channels

I have a Time Warner cable box. Sometimes when I switch channels there is a loud popping noise but not all the time. The sound cable(coax) from the cable box (Scientic Atlanta 3200HD)feeds into my Mcintosh MX135 pre/pro. All my components are fed power from a Panamax 5500EX surge/AC regeneration unit.
Any thoughts on what can be done to eliminate this noise??