I hadn't either, hence why I came here for advice, I'm a novice at this, I know a little about wiring systems in and adjusting gain and all, but this had me sumpted. When I took the amp out I hadn't had any problems with it before. I just went ahead and replaced the subs and amp to be done with it in the truck. My buddy is gonna opem this amp up and check the interals and test everything and play with the gain adjustments and all, and the amp is still good i'll proably use in my celica when I'm done building it.