I moved the LD player from the TV in the basement to the entertainment center in the living room. There are zero issues with it in the basement, but when I use it up here, there is a 60 hz hum that sounds like a ground loop when I change the input on the TV to the player.

At first it was very loud, then I changed cables and it's much quieter, but still there. Thinking it was a ground loop, I connected the chassis of the player to the chassis of the Onkyo receiver. No change at all.

We use the TV to switch inputs between all of our components and the TV's audio out goes to an input on the receiver which we just leave on the same input all the time. I tried connecting the LD player directly to the receiver, and there's still the same hum. In fact, it's considerably louder. It even happens when the LD player is COMPLETELY TURNED OFF and I don't even have that input selected!

After playing with things, I noticed the hum begins immediately as the ground prong of the LD player makes contact inside the outlet, even with the two line prongs aren't touching yet.

What can I possibly do to resolve this? I'm at a loss. I love electronics, but I'm no electrician!

If it matters:
- We're using a battery backup between the wall socket and all of our equipment.
- Neither the TV or stereo receiver have grounding prongs on their cables.

I used to get a ground loop hum on the analog audio outputs from my player (digital output was fine), had to disconnect the ground on the plug to my PC.

Disconnecting the ground on a PC psu isn't a great idea. Unlikely it's double insulated (Class II).

Not really worried about it as I've had it that way for 10 years now without a problem, and all my data and HDD images gets backed up fairly regularly. Plus I've never had so much as a brownout in all the 15 years living in Tokyo.

A very short term cure would be to see what happens if the AVR is turned on last. My suspicion is that the TV or cable service wire is the cause, but with power conditioning you shouldn't be getting any problems. The TV too is hooked up to the UPS/isolator/whatever?
Untangle any cords that are crossed up.
You've never had any other ground loop and related electrical problems?

Yeah, everything there is connected through the UPS, including TV and receiver.

It's a decent unit too. Pure sine wave, I don't want to send dirty power through all of this expensive equipment when it goes on battery.

Does it go away while the disc is actually playing?

It's there during playback too.

I should have a CLD-406 arriving Wednesday. It'll be interesting to see what that one does, assuming UPS workers don't decide to drop-kick it and it still works.

I had a TV that didn't like my LD-V2200 but only while powered off or sitting at blue screen. I did not experience the issue when other players were plugged into this TV or when my LD-V2200 was plugged into another TV. I never looked into it though.