jl 1000/1 v1 screeching on bench no input

[Broncobill93]

My amp was working perfectly and all of sudden quit outputting sound and would just make a load screeching sound even on the bench without input.

Where should i start looking on the input side? cant see anything burnt
have an oscilloscope and tools

 

[nigelwright7557]

Check power supply voltages first.
Apply a signal and see where it goes wrong in amp.