Anthony,
The dual tweeters and dual mid-range speakers of my M80 were intermittently very noisy and periodically cut out completely but the dual 6.5 inch woofers were fine. At first I suspected a poor gold bridging bar connection, but it was solid. Then I removed the two gold bridging bars linking the two pairs of binding posts to isolate the woofer and midrange/tweeter sections. Checking the DC resistance with an ohmmeter, I found that the resistance of the woofer section was stable as expected but the DC resistance of the tweeter/mid-range section varied slowly (charging/discharging capacitor(s) in the crossover network.) Since all four speakers were periodically cutting out, I reasoned that the likely failure was the crossover network and not multiple speaker failures/multiple speaker interconnect failures. Axiom failure analysis confirmed that the crossover network was the problem.
Jim
