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(1) Main Logic Board
The interface board relays data from the host computer to the main logic board. The main logic board’s CPU
temporarily stores the data into local RAM.
It then reads out the data, edits it according to the control program stored in the board’s ROM, and prints the results
by issuing the appropriate drive signals to the printer mechanism.
[Block Description]
a. CPU: HD641300F, CMOS single-chip computer
Controls overall printer operation.
b. EPROM
Contains the program and character fonts (other than Chinese characters) for CPU control.
c. PS-RAM: 128 K × 16 bits
Used as the work area and data buffer
d. S-RAM 8 K × 8 bits
Saves format data and externally defined characters.
e. EEPROM: 1024 bits
Stores printer settings. Settings can be changed by software. (Used in place of dip-switches.)
f. Gate array
Executes various types of signal processing.
g. Drivers
The various drivers convert signals received from the CPU and gate array into the drive signals that directly control
the printer mechanism.
h. DC-DC converter
Converts 24V to 5V.
(2) Interface board
Interfaces the main board with the host computer.
There are three versions, each for a different interface type: RS-232C, RS-422A, or Centronics parallel.
(3) Near-end sensor board
a. Checks the amount of paper remaining on the paper roll.
b. Used to adjust the sensor.
c. Displays errors using the LED.
(4) RESUME Switch
a. Used to set paper.
b. Used in HEX Dump output and test prints.
(5) Printer Mechanism
The printer mechanism is composed of the thermal head, paper feed motor, cutter sensors and presenter (only on the
TUP482.)