Last year, when a client needed a replacement, I first contacted Richard Land, who wanted more money for the service than the official AKG center, did not want to sell me the part outright, and, my perception, was not particularly friendly. I sent the defective CK1 to AKG, Northridge (L.A.) and received excellent, timely and reasonably-priced service ($180).
There is an old-school C451 specialist at AKG Northridge who is an expert in properly replacing CK1 capsule platelets for a reasonable cost (rather than charging the customer for the whole capsule). He then calibrates the new platelet/backplate combo to factory capacitance specs, and also makes sure that the proper spacers are installed.