The internal fan has been making noise and now after 30 min or so we get a loud pop the a descending whine at deafening levels even with the board muted. I'm suspecting an internal supply issue in our GL2400 32 channel mixer. Am i wrong or should I consider other problems.

Hey tifly415, did you ever fix this problem? My church has the same mixer and last night it did the same thing twice during a congregational meeting. No fan noise, but the meters all peg and we get this horrible descending squeal which gets louder as you pull the faders back in a moment of sheer terror and panic. Power it off and back on and it's ok for a while then it happens again. It's happened to me a few times during rehearsals in the past and it definitely is not mic feedback because no one was near the console or doing anything at the time. It seems to be totally random and unpredictable.

I, too, suspect a power supply problem, but it never seems to happen when my troubleshooting gear is nearby. The only thing unusual yesterday was that the mixer was left on almost all day, so it may have been warmer than usual.

Anyone else have the same problem, or better yet, know of a solution?