[. . . ] [. . . ] SB-220 REPLACEMENT RELAY CONTACT/WIRING DIAGRAM (VIEWED FROM BACK CONTACTS OF RELAYS) **NOTE** SOME OLDER SB-220 RELAYS MAY BE WIRED DIFFERENTLY (PINS 1, 4, 7 & 2, 5, 9 FOR RF SWITCHING & PINS 3, 6, 10 FOR BIAS SWITCHING CONTACT CROSS-MATCHING (NEW = OLD) 1 = 12 = 23 = 34 = 4 5 = 56 = 67 = 78 = 99 = 10 A = COIL 11B = COIL 12 NEW RELAY PINOUT PIN 1 PIN 2 PIN 3 PIN 4 PIN 5 PIN 6 PIN 7 PIN 8 PIN 9 PIN A PIN B LARGE BARE WIRE TO PIN 3 ONE END OF 100K RESISTOR & SMALL RED WIRE FROM 120VDC SUPPLY & SMALL RED JUMPER WIRE TO PIN B LARGE BARE WIRE TO PIN 1 SMALL COAX CENTER CONDUCTOR TO TUNED INPUT LARGE BLACK WIRE TO RECTIFIER/METERING BOARD LARGE BARE WIRE TO TANK CIRCUIT SMALL COAX CENTER CONDUCTOR TO RF INPUT JACK OTHER END OF 100K RESISTOR AND GREEN/YELLOW WIRE TO CENTER TAP OF FILAMENT TRANSFORMER LARGE COAX CENTER CONDUCTOR TO RF OUT JACK SMALL BLUE WIRE TO ANTENNA RELAY JACK OR TO SK-220 UNIT RED WIRE JUMPER TO PIN 2 [. . . ] [. . . ]