I was asked to fix a problem with a karaoke set up at the local bar.

The problem is that when we plug the large screen TV in as a monitor, it causes audio feedback through the karaoke speakers.

Keep in mind, there is no audio going to the TV, only video.

The only things I can think of are to make sure the karaoke system is plugged in to the same circuit as the tv. And if that fails possibly rout the video through a VCR first, and then to the TV.

Any other ideas as to what could be causing it and/or what to do to stop the feedback?

 

how about letting us know where the feedback is coming from.

 

Through the speakers

 

looks ilke they asked the wrong guy h:

 

through the speakers connected to the karaoke system.

 

How is the system wired and what kind of system is it?

Is it full on uncontrolled feedback or more like a reverb or delay?

 

It's more of a low hum. I don't know what kind of system it is, but i do know it happens on many different systems. We hire people to come in and do karaoke. The TV is always the same one, and other TV's work fine.

 

My first guess is the hum is probably an impedance mismatch

 

If that is the case, what can I do to fix it/ stop the symptoms?

 

If it's just that TV it might be a grounding issue or it might be an indication the system isn't hooked up right. Isolation of the the TV somehow would probably get rid of the problem, so like you said connecting through a VCR or other component not so sensitive or a dedicated isolation device might help