Dan's small parts specials #3 has Erie 8-50 pf trimmers that should fit bases of the 8-50 used all over Collins equipment. 75 cents each. http://www.danscloseoutsandspecialdeals.com/Dansspecialdealsno3.html -- 73, Jerry, K0CQ, Technical Advisor to the CRA All content copyright Dr. Gerald N. Johnson, electrical engineer