Page: 159Service Guide ML520/521Chapter A Reference ChartsA.2.01 Main Controller Board (FJIM)FunctionThe main controller board contains a microprocessor, EPROM, EEPROM, drive circuitry, 128 KbyteDRAM, sensors and interface connector. The AC voltages from the power supply are rectified andregulated on the main controller board.Firmware05CB: CMOS Dynamic RAM (1 MBit)05CA: EPROM (Program)FusesF1: 125 Volt 2 amp. (AC line fuse)F2: soldered - 2 amp. (protects the +40vdc motor drive circuit)JumpersNONESensorsSNS1: Rear / Top Feed Paper Out SensorSNS2: Bottom Feed Paper Out SensorSwitchesBASW: Paper Path Select SwitchTest PointsFrame Ground CN1 pins 37,38Logic Ground CN1 pin 33+5 vdc : CN7 - Pin 6 (logic circuitry voltage)+40 vdc: CN7 - Pins 29 and 31 (Printhead, Space Motor / Line Feed Motor Drive Voltage)
