Main Pcb - Brother TD-4000 Service Manual

2.3 MAIN PCB

Figure 2.3-1 and Figure 2.3-2 show 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 (4Kbits)
(4) Power supply ON/OFF circuit, FEED button ON/OFF circuit, CUT button ON/OFF
circuit, and 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 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
(12) RS232C interface circuit
(13) Ethernet interface circuit
<For 100/120V model>
Oscillator circuit
7.6MHZ
Photo sensor for
detecting top edge
of media
Cutter home position
sensor
FEED, CUT button
Green LED, Red LED
Cover open sensor
POWER button
Key PCB
Cover left sensor
Fan motor unit
100/120V
AC power supply
Figure 2.3-1 Block Diagram of Main PCB (For 100/120V model)
CPU
850E/MA3
(NEC)
ROM: 256KB
RAM: 16KB
INT
Lock
signal
+8V output
Switching
Power supply
power supply
Switch
shunt PCB
EEPROM
(4Kbits)
FROM 64Mbits
(Max. 64Mbits)
16bits bus
TD-4100N:
SDRAM 128Mbits
(Max. 128Mbits)
USB IC D12
TD-4100N only
LAN IC LAN 9115
RS232C RS232C
IC IF
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
+25V
(for drive power supply)
output
+2.5V power
supply circuit
+3.3V power
supply circuit
+5V output
II - 9
TD-4000:
SDRAM 64Mbits
(Max. 64Mbits)
USB IF
LAN IF
DC motor
for full cut
For tape feed
driving
Thermal head
+2.5V output
(for CPU power supply)
+3.3V output
(for logic power supply)