amp trouble!

Hey there, I'm currently having problems with my marshell amp. I have tried different leads and different guitars to the amp and same problem occurs. The problem is when i am plugged into amp it makes absoultely no sound on clean, no matter what the volume is on, and when on distortion there is very slight sound coming out, again no matter what the volume is at on the amp and guitar. Has anyone ever heard of this problem or had it themselves. Any help would be extremely appreciated! Thanks