Line Noise and Picture Distortion

[JimMul79]

Hi all,

I have a line noise problem, but I didn't find any other posts here that described this exact scenario. I have a Yamaha HTR 5460 receiver hooked up to a small 19" TV that servers as the monitor output. I also have a VCR hooked up to the receiver with normal RCA cables. Finally, I hook my laptop up to the receiver for audio (that connection splits the headphone line into dual RCA). Pretty typical setup I'd say.

The problem I have is when I hook up the cable TV line either to my TV or to the VCR, and have my laptop audio hooked up at the same time. When I do that, I get serious line noise and a distorted picture on the TV. When I don't have the laptop hooked up for audio, everything is fine except for a little static noise at higher volume (but I think that's been there for a while anyways, and it's probably due to a bad speaker connection).

Now the only thing I've been able to figure out is that I only get the extreme line noise/picture distortion when the laptop is plugged into the power outlet. When I unhook the laptop power line (still leaving the audio hooked up to the receiver), the noise goes away and there's no more distortion on the screen.

I thought this might be a polarity issue but perhaps it's a grounding issue as well since the problem goes away when I unplug the laptop from the wall power outlet. I've tried hooking up the laptop, TV, receiver, VCR, etc. to different outlets, but that didn't seem to change anything. I've also switched the inputs for all my components at least twice, so I don't think that's an issue.

Anyone have any advice on how to fix this or work around it? Thanks.

[Smokey]

Finally, I hook my laptop up to the receiver for audio (that connection splits the headphone line into dual RCA). Pretty typical setup I'd say.

That might be your problem there. Headphone output are meant not be hooked up to line RCA audio inputs. Laptop may be loading down audio input on the receiver, thus effecting other connections. Do you have line out on the laptop?

Or your lap top may be creating ground loop. Try different plug location for laptop to see if problem still exist.

[JimMul79]

Yea I'm thinking it is a grounding issue too, I just don't know how to work around it. The headphone jack is the only audio out on the laptop, but the line noise goes away once i unplug the power cord so I don't think that's the issue. I've tried plugging the laptop, tv, vcr, and receiver in different outlets, the same outlet, the same surge supply, etc. with no changes. I always get noise if the laptop is connected to the receiver while the cable TV line is connected to a device that's connected to the receiver (either the TV or the VCR).

Also, when I first set up the connections, I got noise even without the laptop connected to the receiver. Somehow I fixed it (basically by trial and error and messing with all the connections), so that would normally tell me that it's a grounding problem with the cable outlet and wall power outlets. However, I had this same problem in my last apartment with a different TV. So I think the issue is with the receiver, and not the laptop/TV/VCR/power outlets/cable outlet.

I'm basically wondering if there's any tricks to properly ground the connections to the receiver.

[Smokey]

I always get noise if the laptop is connected to the receiver while the cable TV line is connected to a device that's connected to the receiver (either the TV or the VCR).
Also, when I first set up the connections, I got noise even without the laptop connected to the receiver.

If you have cable TV, that probobly is your main culprit as most cable companies ground their cable outside home and have different ground potential as home ground. Have every thing hooked as before, but try to disconnect cable TV to see if same problem persist.

Let us know.