Yamaha EMX660

[milchman]

Hey All, this powered mixer has a intemittant problem , so Im putting the sysmtoms out to see if anyone has some suggestions. I was doing a gig with it yesterday and after an hours time a high pitched squel started coming from the speakers . Im pretty sure it was not feedback noise because we were playing at the same volume and the speaker place was no where near the mics. Turning the master volume down for the mains stopped the noise . When turning the mains back on the noise was gone and after three more songs it came back . We disconnected the monitors from the power amp. tried switching the main monitor switch from main -monitor to just main and also tried runnning the monitor amp instead of the maiins . Nothing seemed to help . I got the amp home last and set it up in my basement to try a duplicate the problem and after an hour or so of having an input of music thru the instrument jack it started to hum , but this time with a low pitched noise. I removed the amp out the the case and set it up on the work bench and started it back up . It has been playing all night with no noise .


It is possible something is heating up ?? What the best way to find this ??