I hope I don't break any rules w/this. A friend & newly-supporting TBer has an SVT-3pro head w/a problem: In 3-4 years of very regular(6-8 hrs/week@Church)use, it has mysteriously stopped producing sound. Lights on, no noise. First time, toggling the mute switch made it go away(or it just happened to go away while toggling the mute ). Next time, it just started working again. We've had it checked by a licensed tech, who found nothing. Again, ... We've since replaced this head(we share bass duties at Church)- not so much due to the problem, but I went Eden, for the tone. Anyway, w/o lying or being misleading about the issue, what would you do to unload this thing, also w/o totally giving it away?