"Buzzing" in Audio When second screen attached using VGA.

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This is related to this:http://www.mac-forums.com/forums/ot...powermac-g4-works-then-doesnt.html#post938453

I installed a new graphics card, a ATI Radeon 7500, in my old 2001 G4 Mac.
It works well.

I used a Belkin ADC to DVI adaptor and a DVI to DVI cable to connect my 19" Viewsonic VA1912w monitor. It works well.

I have an iMic connected to a Yamaha sound system. The audio is fine.

I connected the remaining VGA port on the ATI Radeon 7500 garaphic's card to my Sony Bravia HDTV's VGA port. I have two functioning screen on the Mac.

However, when I connect the HDTV using the VGA cable I suddenly get a "buzz" interference noise on the sound system. Disconnect the VGA cable and the noise stops. Connect it, it comes back.

A grounding problem? Any thoughts? Anyone else experienced this?
 
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Your Mac's Specs
MacMini 14.3, 8.1 & 4.1, OS 13.5, 10.14, & 10.11 & 10.6; Macbook Pro 8.2, OS 10.12.
It is nearly always a "grounding" issue. Tracing just where can be a tortuous process, but start by checking all devices in your setup to see that all are earthed properly. You may have a device that is double-insulated, thus not requiring an earth connection.

The only other suggestions I can offer are:
1. the VGA cable, that is apparently causing the interference, may be faulty. Have you tried another cable?
2. the proximity of the Yamaha amplifier to the HDTV.
 
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Sounds like I'm in for a fun time.

I think I shall start by replacing the VGA cable. Currently i have two joined together to reach the HDTV. I''' see about getting a longer single cable and go from there.

Many thanks for the "feedback".
 

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