Vintage Synth Repair

Hi all. I am working on an ARP Solus at the moment that had a dead osc1, which was easily remedied by changing the 1.87k ohm tempco resistors (r60 & r98) which took care of the dead oscillator, but now the issue I have is that osc1 tracks backwards and badly at that. Osc2 is fine. Stable and in tune. The service manual and schematics available are pretty poor in quality and somewhat topical in nature. Anyone have any idea where to look? I am thinking that z1 thru z5 are the key tracking cv and gate sections of the synth. What is z2 paricularly? It is a beckman ic. Can't find anything online about it... Any hints? Tanx.