system popped when I turned it on after storage

system popped when I turned it on after storage

Hi there, My sound sticks had been working perfectly well, and then I travelled for 3 months and stored them. When I moved into a new flat I plugged everything in, switched all on and it popped and hasn’t worked since. For the life of me I cannot find the issue, Any ideas, please? I am not terrible tech-minded but I learn fast. Any tips or tests I can perform?

ANSWERS: