Popping noise from Summit

[Ucimba]

I got a pair of ML Summits about a month ago and recently started noticing a popping noise coming from the front firing woofer in the left speaker ususally at higher volume. Sounds like the sharp tapping of a pair of wooden sticks. I tried changing power outlets, switched left/right channels, plugged the speakers in a reference power center, etc but still hear the noise when I turn up the volume to 40/100. I also used my MC402 solid state amp to troubleshoot Tube related issues in the MC275 but the noise was still audible at higher volumes.
The speakers are connected to a Mac 275 tube amp and a C2300 tube pre amp with Audioquest Balanced XLR cables (Panther). I noticed that while the speaker is running sometimes the Green light goes off (but the music continues) and then comes back on again. And this is only happening with the Left speaker.
Has anyone had similar issues and what was the solution? Any insight will be greatly appreciated.
Thanks.

 

[Craig]

If they lose power the panel will continue to play for quite a while but the woofer will stop immediately. My guess is that something is causing the power supply to kick off and on. Possibly a loose connector on one the circuit boards inside or something else is causing the power supply to trip off/on. That can be checked if your willing to remove the rear panel to access the power supply assembly. Make sure your powercord connection to the speaker is not loose at either end and causing this. The light should be green and indicates normal function. Could also be a faulty power cord.

The best thing to do is to call ML tech support and utilize their excellent customer support.

But if you're brave enough to go inside yourself to check for a loose connector then you might find this thread helpful.http://www.martinloganowners.com/~tdacquis/forum/showthread.php?t=2090