I have a Pioneer VSX-520 Receiver, when it’s working properly, if I switch it on, it makes a distinct, little, very faint, sort of ticking sound just milliseconds before the front panel comes on and again the same sound just milliseconds before the Speakers come on. Now it only gives me the first tick, no longer gives me the second tick and Yes the Speakers don’t come on. Even when I switch the Sub-Woofer on, I can hear that similar ticking sound just before the Sub-Woofer comes on and right now I can only get sound from the Sub-Woofer and no sound from either the Front Left or Right nor the Surround Speakers. In the past 8 years I’ve owned this Receiver, maybe I’ve experienced this problem 4 or 5 times and maybe this time it’s the 6th time. The length in time, how long the problem would last varies considerably, because sometimes it would last 3 or 4 months or 6 or 7 months. Right now I think it’s been almost a full year since I’ve had this problem. The problem is that for some miraculous reason, without doing anything in particular, one day I would just try to switch it on and my Receiver would work perfectly, it would make both ticking sounds and my Speakers would come on and everything would be perfect, having done nothing, I mean absolutely nothing and everything would be back to normal. I’ve tried ‘Factory Resets’, Unplugging completely from the mains and nothing seems to work. I don’t know what seems to be the source of this problem and I don’t know what seems to miraculously fix it.