I found an old vga to bnc cable that I want to use on my monitor. It is an old Apple once and has R, G, B plugs. I have the apple vga to standard vga adaptor hooked up to it so that it fits my video card, but I don't get any signal on my monitor. I selected BNC as my input on the monitor. The only thing I'm wondering is that my monitor has two other BNC inputs - V and H/C that I wasn't able to use. Could that be why it's not working?