Main Pcb - Brother P-touch QL-1050 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) Flash ROM, SDRAM
(3) EEPROM (4Kbit)
(4) Power supply ON/OFF circuit, FEED button ON/OFF circuit, CUT button ON/OFF
circuit, LED ON/OFF circuit
(5) Head power supply ON/OFF circuit
(6) Full cutter motor driver circuit, and Media feed motor driver circuit
(7) Media type sensor circuit, Media position detect sensor circuit, and Cover open sensor
circuit
(8) Head temperature detect circuit
(9) Cutter home position sensor circuit
(10) Reset circuit
(11) USB interface circuit
Oscillator circuit
7.6MHZ
Photo sensor for
detecting top edge
of media
Cutter home position
sensor
Media type sensor circuit
6 selector switches
FEED, CUT button
Green LED, Red LED
Cover open sensor
Power supply
ON/OFF button
Key PCB
Cover left sensor
Fan motor unit
+8V output
100/120V
AC power supply
220/230/240V
CPU
850E/MA3
(NEC)
ROM: 256KB
RAM: 16KB
INT
Lock signal
Switching
Power supply
power supply
shunt PCB
Fig. 2.3-1 Block Diagram of Main PCB
EEPROM
(4Kbit)
FROM 32Mbit
(Max. 56Mbit)
16bit bus
SDRAM 64Mbit
(Max. 128Mbit)
USB IC
D12
RS-232C
IC
DC motor
Normal/reverse
drive circuit
Step motor
Bipolar constant current
drive circuit
Thermal head
temperature detect circuit
+25V power supply
voltage detect circuit
+25V output
(for drive power supply)
+25V output
+5V power
supply circuit
+2.5V power
supply circuit
+3.3V power
supply circuit
+8V output
II- 8
USB
IF
RS-232C
IF
DC motor
for full cut
For tape feed
driving
Thermal head
+5V output
(for logic power supply)
+2.5V output
(for CPU power supply)
+3.3V output
(for logic power supply)