# Help with fixing hum on Sony str-dg520 receiver



## obtb555 (Sep 10, 2012)

Yes, I'm sure you've all written responses to hum questions numerous times, but I cannot resolve this problem and need help. I have a Sony STR-DG520 receiver, with an AT&T Uverse cable box, Philips DVD and Apple TV all coonected (audio only, not using HDMI pass through). The hum is constant, regardless of volume or input selection. Here are all the steps I've taken to try and resolve the issue:

1. Unhooked every device one by one to find the culprit. No luck.
2. Removed speaker wire from speakers one by one to find culprit. No luck.
3. Placed all devices through same surge protector and have switched wall outlets. No luck.
4. Moved speaker wires away from power cables as far as possible. No luck.
5. I have only one three pronged plug in my setup. Placed a 3-to-2 prong adapter on the three pronged plug to try and break ground loop. No luck.


I've read about installing a ground loop isolator into systems to break the hum, but since I haven't found any of the devices to be the cause of the hum, it seems like that's not the way to go. My receiver doesn't have a ground screw on the back, so if I was to run an earth ground wire from it, I don't know if I could use just one of the screws in the back panel or not. I've also read about failed electrolytic capacitors causing hums, but I don't know where one would be located on my receiver or how to replace them.


Someone please help! This hum is the kind of thing that can drive perfectly sane people to the nut house!


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## JimE (Apr 16, 2009)

As it's a receiver, you can tune FM right? Then disconnect all devices, all speakers, and test using headphones. If you still have hum, it's likely the receiver or the AC input. But with everything disconnected, most likely the amp.


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## obtb555 (Sep 10, 2012)

I don't have a set of stereo headphones available to me but I'll track a pair down. Any other suggestions? Oer ways I haven't listed to break a ground loop?


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## obtb555 (Sep 10, 2012)

I've removed the receiver from its usual location and unhooked all devices. I moved the receiver to a outlet in the next room and hooked in only one of the speakers, still got hum. I tried another speaker, with another outlet, still got hum. At this point, I think it's safe to say that my receiver is causing the issue. 

Why is this happening?


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## JimE (Apr 16, 2009)

Loose or faulty component most likely. Unless it's under warranty, it's likely cheaper to simply replace it. Unless you know someone with a repair shop.


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