When the speakers are running off the amp, Check the "continuety" using a multimeter to see there is a closed circuit for each speaker to eliminate it being a broken wire or contact ant any point between the amp and speakers.
As previously mentioned by another post, check using a different set of Phono leads.
N if u can get hold of one, then test a different amp in the same position!
Has the amp light changed colour or has an additional ligt turned on along with the power (protection light)
If thats the case then u either have an earthing problem or your amp has packed up!
