Last week, my kid gave me a 1976 Sony AVC-1420 black-and-white video camera for my birthday. The only output connection it has is a BNC connector, so I modified a BNC cable that I had by putting an RCA jack on one end. That worked perfectly, so we were able to play with the camera last weekend and thoroughly test it out.

So, today, I made that cable a little more permanent by soldering the RCA connector in place. Previously, I just had the wires twisted together. I also soldered a second RCA connector to one of the other cables, so I now have two BNC to RCA cables. From there, the plan was to hook the two BNC connectors to one of my four video switchers, and that’s where I ran into trouble.

The video signal worked flawlessly, but I suddenly had a horrible ground loop that played through the stereo system that I have installed in the same rack as the video switcher. I connected the output of the video switcher to the input on my CRT TV. The TV is connected to the receiver in the rack, but I didn’t have the TV input selected on the receiver. I was using the receiver as a second zone from the receiver in the living room. Because of that, the hum from the ground loop could be heard through all of the speakers wired to the Zone 2 output of the living room receiver.

I have a Juice Goose power strip that allows me to isolate the ground on each device plugged into it, but it had no effect. At this point, I think the video switcher might be wired in some funky way, but it’s going to take some experimenting to figure out what’s going on.

The good news, though, is that the video signal works perfectly, so as long as I keep the receiver turned off, I don’t have to listen to that awful humming.