Before we can help we need more information.
#1) Did you just buy it or did you own it for a while and it was working and now it doesn't?
#2) If it is new, then we need to work through all the switches and settings. It is easy to "open circuit" an amp by having switches and jumpers not set right. Do you have operating instructions?
#3) What are you using as a signal source? Tuner, CD player, ???
#4) Is there a protection circuit? For example, either a "standby light" or perhaps just a relay switching?
#5) Is there ANY sound at all with a speaker attached? Hum? Hiss? Any "clicks" when you switch SOURCE or other switches?
Lets get some preliminary info and we'll trouble shoot from there.
Paul