One channel not working

hi,
i've bought from ebay one Verge VGA285 as is condition. one ofw the channels is working fine , the other not, when i adjusted the input level the non working channel started but it was like a protected mode because was working for 1 sec then off for 1sec and so long , i've opened the aplifier and i've switched between (left to right channel) the final transistors thinking that one of them if burned but they are fine , when i've tried again to see if it's working i've noticed that the final transistors on the side of the channel that is not working are overheating very fast...any ideea , any schematics for the amplifier?
thank you