I have a Spider 3 75 watt amp and it sounds great for about 15 minutes, then all the lights go out except for the LCD display and it goes silent. It will then make a small popping sound and flicker the lights for a half second about every 30 seconds. It is not hot to the touch at all, and if I turn it off and back on, it will resume lights and sound for about a second before it loses it again. If I leave it off for awhile and then try again, its fine for another 15 minutes. I'm guessing something internal is getting warm, but nothing I can touch without taking it apart feels warm. Any ideas? Thanks.