Humming/Buzzing/Drone like noise when HDMI is connected.

[Merc1032]

Hey Everyone,

Im experiencing a strange problem when I playback live tv over sage.

A quickie about my setup.

Cablevision Coax>SA4200HD STB> Component Cables> HDPVR> Usb to PC> HDMI from mother board> TV

The problem only occurs when I select live tv from sage. If I am watching a pre ripped DVD, video from the online services menu, or listening to audio files, there is NO buzz. Once I switch over to live TV the buzz begins. It is rather annoying and has forced me to temporarily connect the tv to the cable box via component directly , bypassing sage and the pc to keep the gf happy.

What would cause this? Im using the same wire for the other audio/video forms..only a buzz on live tv. Some kind of ground loop? The STB is still "on" when I am watching online videos/ripped DVDs tho.

Any help would be appreciated.


Thanks!

[tmcfarland]

I had a nasty buzz some time ago, and it wasn't from drinking cheap wine. I read somewhere that cable boxes are often the cause, so I switched the audio between the cable box and the amplifier from coax to optical to isolate the cable box - problem solved. Hope yours is as easy to find & fix ... good luck!

Originally Posted by Merc1032

Hey Everyone,

Im experiencing a strange problem when I playback live tv over sage.

A quickie about my setup.

Cablevision Coax>SA4200HD STB> Component Cables> HDPVR> Usb to PC> HDMI from mother board> TV

The problem only occurs when I select live tv from sage. If I am watching a pre ripped DVD, video from the online services menu, or listening to audio files, there is NO buzz. Once I switch over to live TV the buzz begins. It is rather annoying and has forced me to temporarily connect the tv to the cable box via component directly , bypassing sage and the pc to keep the gf happy.

What would cause this? Im using the same wire for the other audio/video forms..only a buzz on live tv. Some kind of ground loop? The STB is still "on" when I am watching online videos/ripped DVDs tho.

Any help would be appreciated.


Thanks!

[Merc1032]

Still cant seem to figure this one out. In fact, the plot thickens.

I temporarily connected the STB directly to the tv again via component so that we could watch tv without the buzz. I left the HDMI cable from the PC connected to the pc and the buzz is STILL there! Even with the PC powered down and the tv set to component, untill I unplug the HDMI cable, it drones. There are also noticeable purplish horizontal lines ONLY when there are black areas of the screen. For example if I am watching something letterboxed, or pillarboxed the black area of the screen scrolls these purplish bars. This happens whenever the HDMI cable is connected, if I am watching tv directly connected or through the HDPVR and Sage. Unplugging the cable makes the sound, and colored lines go away instantly. Unfortunatly unplugging while using Sage is not a option because I need it to see the screen.

Im going to play around some more today. This ring a bell to anyone?

Thanks!

[jtennison]

Audio hum is frequently caused by electrical power cord interference. If the HDMI cable has poor shielding, or if it runs along next to a power cord, that may be causing the hum. Try to insure that any audio cable is at least 6-8 inches away from power cords (it usually OK to cross power cord at 90 degree angle), or is heavily shielded.

No idea about the purple lines!

[SHS]

Merc1032 are you using Audio RCA jack to the HD-PVR?.
If yes then go to RadioShack get a Audio Ground Loop Isolator Model: 270-054 | Catalog: 270-054
And add Viewsonics Cable Ground Loop Isolator Model: VSIS-EU or Jensen Transformers Model: VRD-1FF
As for the purple lines
1: You're using a video resolution that isn't supported by your graphics card and/or monitor. Try using a more diff resolution to see that helps.
2: Your screen is possable damaged. What you're seeing is proof of that.
3: Your GPU is damaged, either from overclocking or overheating.

[texneus]

Agreed, you have the classic symptoms of a ground loop, but the fix is to correct the ground, not kludge something to it. The most probable cause (from experience) is your cable system ground is floating. To verify, plug everything back together as normal (verify hum exists), then unplug the coax from your STB. If the humming stops, call your cable company and they should fix it. It could be moisture has gotten into a buried cable or the bond at your service entrance has corroded or come undone.

If the humming continues, you'll have some work to do as these are never easy to track down. My suggestion -

Plug everything into the same AC power strip. If this corrects the problem than your house wiring could very well be defective. After that, start unplugging all connections one by one on each device and try to isolate it to a specific source. If you can, reverse the plug on that device.

[sic0048]

Are you sure the purplish color lines only appear in black areas? Or could they be across the entire screen, but simply cannot be seen in a regular color screen shot?

I suspect the video issue is related to the ground loop too. I've definitely seen a purplish color line that scrolled up and down the screen on a TV where the wires were run too close to HV power.

Have you tried swapping out HDMI cables yet? Perhaps that cable is just defective.

[Merc1032]

Figured it out.

The problem was coming from the coax that runs into the apartment. I would assume it was not properly grounded downstairs or something. I dont have access to the basement and I didnt want to attempt to call the super and explain a media center problem, lol.

I have had the whole client plugged into my UPS which I just remembered has inputs for coax as well. I took the cable at its first point of entry into the appt and hooked it up to the UPS and outputted that to the splitter that feeds my modem and STB. Turned on the tv and behold! NO more colored lines or buzz!

Thanks for the suggestons guys.


Joe

[texneus]

I'd still lodge a complaint. A floating ground is a potential saftey and equipment hazard. Odds are you are not the only person having problems, and in the event your equipment (or yourself!) are damaged, you have a record that you exercised due diligence to correct it.