Main Pcb; Media Type Detect Sensor Circuit, Media Position Detect Sensor Circuit And Cover Open Sensor Circuit - Brother P-touch QL-700 Service Manual

2.3 MAIN PCB

Fig. 2.3-1 shows the block diagram of the main PCB. The main PCB consists of the
following components.
(1) CPU (Including ROM and RAM)
(2) EEPROM (4Kbit)
(3) Power supply ON/OFF circuit, Feed button ON/OFF circuit, Cut button ON/OFF
circuit, LED ON/OFF circuit
(4) Head power supply ON/OFF circuit
(5) Full cutter motor driver circuit and Media feed motor driver circuit
(6) Media type detect sensor circuit, Media position detect sensor circuit and Cover
open sensor circuit
(7) Head temperature detect circuit
(8) Cutter home position detect sensor circuit
(9) Reset circuit
(10) USB interface circuit
(11) 2Mbit SRAM
(12) 32Mbit Flash ROM
USB IF
EEPROM
4Kbit
Media type detect
circuit
5 selector switches
Cover open sensor
circuit
Cutter home position
detect sensor circuit
Media position detect
sensor circuit
Photo sensor
ON/OFF button
Feed, Cut, Editor Lite
button
LED (Green, Red),
Green LED
AC power supply
8bit bus
INT
CPU
V850ES/JH3-H
(RENESAS)
INT
ROM: 256KB
RAM: 40KB
INT
Switching
power supply
Fig. 2.3-1 Block Diagram of the Main PCB
Oscillator circuit
6MH
DC motor drive circuit
Normal/reverse
drive circuit
Step motor
Bipolar constant
current drive circuit
Thermal head
temperature
detect circuit
+25V power supply
voltage detect
circuit
2Mbit SRAM
32Mbit Flash ROM
+25V output
+8V output +3.3V power
supply circuit
II - 8
Z
DC motor for
full cut
Step motor for
media feed drive
Thermal head
+25V output
(for drive power
supply)
+3.3V output
(for logic power
supply)