Trio™ Service Manual
0070-10-0591-01
1 - 13
Theory of Operation
Hardware Overview
CPU System
The CPU system is the core of the drive board. Its task is to receive the data from the host and
generate lattice messages after calculation using a specified algorithm. These messages are
then sent to the thermal head for printing. The CPU system can simultaneously collect data
from both the thermal head and the drive board and display data sent to the host.
Power Conversion
The recorder requires the system to provide two voltages: 12 V and 5 V. The 5 V is directly
driven by the logic and analog circuit of the drive board and the thermal head. Its current is
less than 150 mA. The 12 V is converted into 8 V (by the DC/DC on the board) to drive the
thermal head and the motor. The current required is determined by the printing content and
ranges from 0.5 A to 2 A.
Motor Drive
A small motor is used to control the paper movement at the thermal head. The processor on
the drive board uses two motor drives IC LB1843 V to control and drive the motor. These two
IC’s use constant current to control and drive the motor.
Status Detection
To correctly and safely control and drive the thermal head and the motor, the drive board
must use the sensor inside the thermal head to detect the following signals: the position of the
chart paper, if the chart paper is installed and if the temperature of the thermal head has
exceeded the limit.
Key Test Points
NO.
NAME LOCATION
FUNCTION
1
12 V
JP3.1
Power input, range: 10~18 V
2
GND
JP3.2
Power and signal ground
3
VPP
U7.8
Power supply for heating thermal head and
drive motor: 7.8 V~8.4 V
4
VCC
U1.14
+5 V supply: 4.75~5.25 V
5
RESET
U3.10
CPU reset signal. At high level(>2.4 V) after
power-on
