Although here, in Madrid area, there are a couple of synthesizer technicians, I am actually doing myself all the mods and upgrades to my studio gear, as I have enough knowledge and soldering/upgrading skills to keep my equipment as it best, changing EL panels for LED ones (and removing inverters), cleaning/substitution of potentiometers, SCSI2SD installations, recapping, etc etc... For finding parts, you know... eBay international sellers use to help a lot for getting parts, as patient is enough, you can get them sometimes for a "reasonable" price :)
José