Hi, The issue with the tuning is most likely the optocoupler - see Stefan Huebner's excellent blog on this, which also shows how to diagnose it... http://huebnerie.de/blog/?p=318
The part is readily available from Australia (it resides on the KLM366 voice board.) - http://www.ebay.co.uk/itm/HTV-4E-P1501-REPLACEMENT-PART-OPTOCOUPLER-HTV-P-1501-KORG-POLYSIX-PHOTOCOUPLER-/321638416753?pt=LH_DefaultDomain_15&hash=item4ae324c171
The part is readily available from Australia (it resides on the KLM366 voice board.) - http://www.ebay.co.uk/itm/HTV-4E-P1501-REPLACEMENT-PART-OPTOCOUPLER-HTV-P-1501-KORG-POLYSIX-PHOTOCOUPLER-/321638416753?pt=LH_DefaultDomain_15&hash=item4ae324c171
As for the drone gliss issue - this sounds like the 367 battery board hasn't been fully sorted... I had something similar, and if I recall correctly, it was down acid damage under the cpu... not that it's necessarily the same for your board...