i bought a peavey delta blues amp from a fried of mine. he said the amp worked great and sounded good untill a trip back from vegas and now it doesnt work.

i only paid 250 for it but i need some help figureing out whats wrong. the amp turns on but no sound comes out. using the external cab out still gets no sound. the speaker cone looks perfect. any ideas on what could be the problem. this is my first all tube amp so im kind of in the dark here.