ok, here's info re: kairn updates:
Kairn introduced - mar 91
Back panel changed - clearance around ph1 & ph2 inputs increased to prevent earth-loop - may 91, serial #1100
Software change - additional user functions 7 - 9 added - mar 92, serial #2384
control board upgraded. Allows kairn to be used in knekt system w/o any hardware mods - apr 92, serial #2490 (approx)
kairn-pro introduced - aug 92, serial #'s n/a
brilliant switch-mode p/s fitted as standard. part #'s changed to kairn/sps & kairn-pro/sps - dec 93, kairn serial# 5000, kairn-pro serial# 5000
brilliant smps enhancement fitted as standard
(sound improvement) - oct 94, kairn serial# 5545; kairn-pro serial# 5309
software changed - add'l user functions 10 - 12 added. Also, this version of software allowed kairn/kairn-pro to be used in knekt system - nov 94, kairn serial# 5653, kairn-pro serial# 5309
slimline brilliant p/s fitted as standard p/s upgrade - oct 95, kairn serial# 7000, kairn-pro serial# 6000
hope this helps, doug s.