School Bus Radio/PA System Diagram?

[Tone]

Has anyone come across a wiring diagram for the Panel Mounted type PA/Radio systems?
The bus audio system seems to have speakers wired in Series(?) Left channel pair in series and Right channel pair in series.
The PA amp and wiring in bound and out bound is "unique" to other car stereo wiring I've ever delt with. ( not saying much )

Any help is great.

[wmah]

Although my short bus didn't have any speak wiring or even a radio I have seen the piss poor wiring that those buses get for speakers. Cheapest 4 channel radio they can get and 2 speakers per channel and that is if they even wire it up that way. I was in a bus for years with the 8 speakers in it. Well I unhooked 4 of them and ran new wires back to separate the speakers into the 4 channels properly.