Have you checked with the Kenwood authorized service centers to see if they can repair it. Just because Kenwood no longer supports the radio doesn't automatically translate to the companies that are their authorized repair facilities will no longer repair the radios. Now, you should still ask if they still have 100% parts availability and if not, what parts relevant to your repair (based on what you say is wrong) may not be available, and how can they handle repairs in those situations (e.g. do they have parts radios available to scavenge the parts from).
There are also some shops or folks that aren't authorized repair folks that may be able to help repair your radios (don't let the not being authorized worry you, since your warranty is probably no longer valid anyway). A few are below to help you get started searching for the right one for you and your radio. (Note, I can't vouch for them personally, but they'll help you in your search)