Actually through more research I was able to answer my own question:
Tom Cadawas
Cadawas Acoustics
92 Oneida Avenue
Staten Island, New York 10301
718 981-9138
Tom Cadawas was former QC and service manager at Marantz in the company's Golden Days. This is the person whom Saul Marantz recommends to work on these tuners. Thanks to Wemcl and Jvogt for their comments. Anyone else with info or comments on getting the best RF performance from these tuners?