I think you mean Dean Nissen? If so, Dean was the last factory Phase Linear service manager at their Lynnwood Washington location.
Dean and I shared a Phase Linear web site for many years on AOL until October 31, 2008. A link to an archived copy of it should appear below this message. NOTE: Some links no longer work
My house in Shoreline, WA is just (2) doors down from Dean's. We spent 25+ years working on weekends restoring Phase Linear products.
NOTE: I am currently living in Connecticut but still own the house in Shoreline, WA.
Dean recently retired from his day job and I retired from mine nearly 5 years ago.
I last visited Dean in September 2019 just before his retirement so I am not sure how active he is in repairing Phase Linear gear. However, I think he is slowing down a bit and may be supporting all of his old customers. I'm not sure if he is taking on any new ones.