Lexmark Optra C710 Service Manual - Page 112

5016-001 FRU 2 Interlock Switch S2 Action Switch S2 has two functions. Two terminals control +24 V dc to the engine board and four terminals control the AC line voltage to the fuser lamps. Terminal A3 (red wires) and terminal B3 (blue wires) control the +24 V dc supply to the engine board. When this circuit opens, a Close Door message displays. CAUTION: Be careful when checking the voltages on switch S2, as the AC line voltage may be present on terminals A1 (brown), B1 (yellow), A2 (brown) or B2 (yellow). Check the voltage at terminal B3 (blue wires). It should read approximately +24 V dc. • If incorrect, go to the "Printhead Service Check" on page 2-77. • If correct, check the voltage on switch terminal A3 (red wires). • If incorrect, check the switch for continuity and proper operation. • If correct, check the cable from the wires. • If incorrect, check the switch for continuity and proper operation. • If correct, check the cable from the switch to the engine board. • If incorrect, replace the cable. • If correct, replace the engine board. 2-46 Service Manual