Availability of the switches, if ITT mini-types are used..? EDIT: the now not longer produced switch type is named "ITT Dialastat"
Also check routing and EQ switches for exessive noise when switching.
Check if dynamics VCA's are DBX2150 or Aphex1537 types. The Aphex types are not easy to source at all.
If plasma meters, check that these light all the way without flickering. Flicker at max. light indicate soon-to-be-changed bargraph..
Other than that, this is a great desk - and not hard at all to service.
Jakob E.