Car Stereos: Alpine 7893, speaker wires, fuse

Question
my unit go off after set the volume over 20 also the fuse on yellow wire.
 Please thanks for any help.  

Answer
Alex, It sounds like one of your speaker wires has a short in it.  Usually this type of short is not very apparent, because it only totally shorts at high volumes.  The lower power of lower volumes is not enough to make the short.  I would check all speaker wires for wear spots.  Then, double check negative ground wire and be sure it is attached properly and securely to the chassis.  Hope this helps, Scott