Brother International HL-1660E Service Manual - Page 33

CHAPTER III ELECTRICAL SYSTEM Electric signal levels are expressed by "High" (approximate the supply voltage) or "Low" (approximate 0V). Signals with hyphen or slash, such as -FSRD or FSRD/, are low-active and signals without hyphen or slash, such as FSRD, are high-active signals. 1. MAIN PCB 1.1 Outline The Main PCB consists of the Video Controller Circuit and the Engine Controller Circuit. The Video Controller Circuit performs the following functions. (1) Converts data received from an external device, such as a personal computer, through Centronics parallel interface or RS-232C serial interface into video data and transfers it to the Engine controller circuit. (2) Displays the current printer status in LED and LCD, and enables settings from the control panel. The operation sequence of the printer controlled by a microprocessor in the Engine Controller Circuit. The Engine Controller Circuit outputs signals to drive the various loads on the laser diode, scanner motor, main motor, etc. according to the print commands and image data from the external device. Video controller Main PCB Main CPU MB86832 CDCC (bolse) IF PC RS-232C IF PC ASIC MB87F1610 FONT CARTRIDGE IC CARD (PCMCIA) +24V Regurator MIO BOARD MIO RELAY (CONNECTOR) PCB Engine controller MASK ROM 32M mask 2 4MB DRAM 16M 4 8MB DRAM (SIMM 2 slots) 64MBmax. EEPROM 24CO4 4Kbit Gate Array µPD65632GF(IO PORT. ENGINE) Engine CPU M38063 +24V +5V GND CONTROL PANEL Low-voltage Power Supply Figure 3.1 Main PCB Block Diagram III - 1