quad 77 amp dead!? help needed

[jimmytwos]

my quad 77 amp seems to have self destructed! it was playing fine, then suddenly the volume went to max, all by itself! unplugged it and it powers up and switches inputs etc but there is no sound! gutted🙁

2 fuses had blown and were replaced with same type but its still silent.
can anyone help?

cheers, jim

 

[jaycee]

Are you sure your speakers are intact?

 

[jimmytwos]

yep, luckily. just checked! got my meter out and there are a set of test points on the pcb. they read -/+ 8vac & 5vac. they measure below that.