Hi!

You need a scope to trace the lack of signal back from the
output to the output of the video jungle/sound card that is
used in almost all sets. Do you have a scope, do you have
a schematic????

I used to have a scope, but a basement flood "ate" it and I've never
looked into replacing it.

Nor do I have a schematic. However, the circuit itself seems pretty
straightforward, and with a little luck and some careful work, I think
I can get through it.

William