Aleph L question

[nsx51]

After replacing the selector switch on my Aleph L (serial #5763) with an Elma 04-1264, there was no output. I discovered a small 6 rocker switch on the circuit board with all the rockers in the off position. Moving them to the on position solved the problem, but since I didn't know the purpose of the switch, I started wondering if all 6 should be "on". Any info or advice appreciated.
While searching for info about this switch I came across a post that said replacing the volume control resulted in a big improvement. Any thoughts on this?
Thanks.

 

[generg]

May be this helps.....

 

[nsx51]

Thanks, generg. Just what I needed. Any chance I could get the rest of that schematic, or a link?