SSL Eq 502 Problem

Hi,
I'm looking for somebody who has already tried to make an SL502eq
working as a unbalanced effect unit or better an SSL tech
(even if they don't like the 5000serie)

I've bought cheap two SL502eq modules,and powered them with
+18 at pin 16
-18 at pin 19,20,22
+6 at pin 15
-24 at pin 21

and connected:
unbal in at pin 31a
unbal out at pin 30a
(the link for bal/unbal selection is at the right position)

It looks like it works:when i push a button its led get on.
But no signal is coming out of the unit....

Maybe it is more difficult and complicated than I thought.

So help is needed...Thanks

Do I have to apply some voltage at any pins in order to make this unit working as stand alone eq?

I've been staring at the schematic for ten minutes and find myself utterly confused.

Ok now I'm having both units working but when I bypass the eq the signal is cut....
Any idea ssl masters :roll: