Sequential circuits samplers

I just received this yesterday only to find one of the voices are dead.  Everything else works fine.  I swapped filter chips between a working voice and the dead one and had no success.  

So it appears to be something more serious.  Anyone know what the next step is for determining the cause?  I am not technical enough to fix this myself, so if it's going to require an expensive investigation by a tech, I may have to just send it back for a refund.  

(Also, does anyone know how to calibrate the filters?  Mine are somewhat all over the place and there are no trimmers inside to tweak. I assume a service manual might explain this?)

Thanks!

Another question regarding filter:
Does anyone know what the small pcb is that hovering over the filter chips?  It is connection to one of the pins of each of the chips (pin 8 or 15 depending on how you look at it).  I was wondering if swapping filters might somehow not work if each filter had to be in a specific place relative to it's wiring placement on the hovering pcb (this doesn't seem totally logical, but then again, I've never seen filters attached like that.)

Sorry, I should have investigated further before posting last message (I realize now that little pcb is for the individual outputs.)