Vintage Synth Repair

Howdy all, I have recently moved and when I used my Moog for the first time at my new apartment, I noticed that my resonance was very weak. When I have the res turned all the way up, it sounds like it were turned up halfway. The filter used to self oscillate, and no-longer will. Other than the resonance being attenuated, I have observed no other changes. Looking at the schematic (below 4100) for the filter section, there is: a trimmer, a pot and a lot of ICs, things that tend to go bad from my limited experience. I will be trying to fix this problem soon, and I am curious if anyone has any ideas of what I should be looking for. I have the schematic and a DMM, but no o-scope. Any help would be appreciated, and I will certainly share my results, or lack of with the group. Thank You,Ben