Vintage Synth Repair

Hello Everyone,
 i just bought a Moog Opus 3 from someone for $400, which is a hella
deal considereing its near mint with slight issues.  Ne ways i powered
it up and played it for a about a day on it and then the filter board
when out.   
        Can anyone specify what parts i should buy to replace the
filter section.  im thinking of getting the parts from VINTAGE
PLANET.com  but i not sure exactly what i need. 
       IM also trying to bring back to life a Korg Delta, Roland VK-09
and Roland Juno 106 if anyone has any ideas.

i found out that on my keyboard i had  the preset/variable switch
broken off and was in the preset mode.   so the filer section does
work it just needed to be in the variable mode.   just thought id wrap
that up.