I use an old Exposure Super XV integrated amp. Unfortunately, it won't turn on, and I went to a stereo repair shop for help. It turns on now and plays music. What's frustrating is it sometimes plays no music , but emits through the speakers a noisy sound, like buzzing/humming sound, which I don't like most.

I'm not an expert in this, so any guys have some experience to deal with it please advise. Perhaps the amp is totally broken or they failed to fix it?

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