Sir Carl_0201 . . . . . .
Thats good ! . . .now we don't have to worry about the possibility of any speakers being the fault.
Basically what you are now having come from the surround speakers is a weak "pink noise" and in order to even hear that noise, we must have several earlier gain stages working properly.
Next I would ask you to use a surround music source that you have used MANY times before and KNOW that the unit was working with proper Surround Sound, in the past.
Probably being a certain well played video that you have.
Then go to your operators manual on the surround sound operations and read and compare switches and settings to what you presently have on the unit.
What I am basically wondering is if a switch is in a wrong position or that the volume for the surround sound has just been turned down by an error on your part or ANOTHER person /child that in trying to. get your system working, was just "punching buttons" in order to get sound from the unit.
I think that this manuals pages 19-20-21 info and adjustments will be the same as your units , if your manual is not at hand.
http://service.us.panasonic.com/OPERMANPDF/SCAK600.pdf
In the interim, I will draw up a Surround Sound signal flow path for that set, then further troubleshooting might be just as simple as using a piece of hook up wire and a DC blocking / coupling capacitor to track that signal stage by stage.
73's de Edd
.