Tally T9020, Maintenance Manual

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2.3.9 Power supply
This section explains the power supply of the printer.
The power supply o5 V to logic circuits and +24 V to the printer mechanism driver.
AC voltage is supplied to the heater in the fusing unit.
Figure 5220-11 is a power supply block diagram
• Overcurrent prevention
– If the voltage exceeds the specified range in terms of +24 V or +5 V, every output
voltage is automatically shut down by the overcurrent protective circuit.
• Overvoltage prevention
– If a -5 V overvoltage state occurs, all output voltage is shut down by the +5 V over-
voltage protective circuit.
– If a -24 V overvoltage state occurs, all output voltage is shut down by the +23 V
overvoltage protective circuit.
• PWSTOP signal
If the printer detects an alarm state, it generates a PWSTOP signal to forcibly stop power
output.
The factor that stopped the power is retained for about one minute after AC input is
turned off.
GID 5220
ACIN
H
F1
SW
Filter
F2
Filter
Surge
control
Rectifier
Smoother
Main
switching
PW&
control
Fusing
unit
ON/OFF
Input
current
1
3
CNAC
Feedback
T01
Fuser
unit
ON/OFF
Voltage
sensor
PWSTOP
+24 V
rectifier
Smoother
+5 V rectifier
Smoother
Voltage control
OVP
PWSTOP
Filter
Filter
12
24VH 6
*HTON
3
PWSTOP
8,9 10,11
+24V SG2 4.5
+5V
6.7
SGI 2
FG
CNPW
N
FG
Figure 5220-11 Power supply block diagram