I don't have circuit diagrams for very old Furuno IF pcb - If-4435-3 and for RF-4476-1. That is for very old Furuno radar. So, I`m kindly asking for help, if someone have. Radar us FR8030D.
Service manuals that include those types of details are only available to authorized Furuno dealers. You might talk to your dealer and see what they might have.