first check ground and power conections on the amp AND the car itself. second chech that the amp, speakers, and RCA's are wired in phase especially if you have a dual voice coil sub. next try the onboard crossover and gain settings. if your deck has an internal crossover or time corection processor check that that is tuned correctly. if all else fails replace the inline fuses and amp fuse then open the amp and ckeck it out. might just need some compressed air to clean it or maybe there is a loose internal wire. (grab a multimeter)
might not hurt to contact Alpine on it if nothing seems to work.
ever since my first deck ive never bought anything besides alpine, i hate to see someone have problems with such an awsome line of products.
