Mixer stuck in solo mode

[wookie]

So last night I noticed my Behringer MX2642A mixer is stuck in solo mode.  All the solo switches are off.  The pre-fader listen / solo mode selection switch still seems to work, as do the solo lights on each channel.  The solo switches on the sub-groups and aux returns don't have an indicator light so one of those could be stuck on I suppose.

I didn't have time to take it apart last night, but I was able to find a schematic on line today at work.  I was wondering if anyone had any experience trouble shooting this sort of problem in a mixer and they could pass on some tips (common fail modes sort of thing).  I'm guessing it should be fairly straight forward to trouble shoot, but just tedious as there is so many places this could fail.

[a soBer Newt]

I would make sure that all of the switches are up I had this mixer and every now and then someone would mess with it and the aux would get soloed or pfl would get switched

[wookie]

Good point.  That's what I thought it was at first two.  My 3 year old boy, Lucas, loves to muck about with the mixer's mute and solo buttons because they light up.  I went over all the switches a few times, and haven't found any left down or sticking so far.  I'm hoping he just hammered on a switch too hard and damaged the mechanism or maybe just touched the mixer with sticky fingers and it needs to get cleaned.  Guess I'll find out soon enough!

[TimWaldvogel]

A good clean always seems to help