Genicom MatrixPrinter LA36 - Manual (Page 106)

5-19
The LA36N/LA36W controller (Figure 5.17) consists of an printed circuit board, called the printer control board
or the main board with ROM. The MPU controls operation under control of programs in ROM.
(1) Printer control board (ROM board)
The printer control board governs the interface, memory, and mechanism. It is also called ROM board. The
name on the Recommended Spare Parts List is “main board with ROM”.
Interface:
The LA36N/LA36W provides two types of interface –– Centronics parallel and RS-423 serial. Interface drivers
and receivers convert signals voltage levels.
Controller:
The controller consists mainly of the MB90706, alarm detector (voltage comparator), and reset controller. The
MB90706 controls interface communication with the computer and memory devices, RAM, ROM, motor
drivers, and print head pin magnet drivers (Figures 5.20 and 5.21).
Memory:
Memory consists of program ROM, character generator (CG) ROM, RAM, and EEPROM.
Drivers:
Drivers include print head and motor drivers and an alarm detector (voltage comparator). The print head and
motor drivers increase power, and supply it to the print head, the carriage motor, the paper feed motor, and the
optional ribbon shift motor.
Alarm detector:
The alarm detector checks the level of +34 V for each driver and the temperature of the print head.
(2) Power supply unit
The power supply unit supplies power to logic and driver circuits on the printer control board.
(3) Sensors
Sensors (phototransistors and a microswitch) detect status of the printing mechanism such as left-end position of
the carriage, paper presence on the platen, setting position of the paper select lever, and installation of options.
(4) Control panel
The control panel –– (7 push-buttons, 16 LEDs, a buzzer, and a control LSI) enables the user to communicate
with the printer.