I have had this gem for almost 20 years now, and am in no way ready to let it die... Over the past year or so, for the second, maybe third time now, when I'm playing through channel A (crunch), The sound will fade out till it was very faint, sometimes completely, and then fade back in here and there, sometimes back to full volume, sometimes not.  If I turned up the gain to almost 9 or 10, it would blast back in and work for a few minutes and do it again.  I play it through an Ampeg 4x12 celestion cab (bought the head/cab together), and it has been flawless since day 1.  I have a Jackson Dinky and a Fender Strat that I kinda rotate between, and a Zoom 505 effects pedal, all of which I wouldn't think are causing this.  I treat the amp with the utmost care, so it's not that.  The local music shop where I bought it is still around, and have had it repaired these times through them, and apparently it was a capacitor issue.  Anyway, this is becoming too repetitive, and would do mostly anything to not have to replace it.  So, I just dropped it off today for analysis, but if this is occurrence #3, am I just throwing away money to fix it and will only have it happen again?  Is it simply time to look for a new (and inferior for metal) head?  Has anyone experienced this issue before?  Are the guys repairing it maybe morons?  They are an authorized Ampeg dealer/repair facility, so I have faith in them.  Any info or tips would be appreciated, if I pay to fix it this time and it ends up happening again, I think I'll loose my mind!  Save my SS-150!!!    Thanks...