Power Supply Overview - Epson DFX-8500 Service Manual

DFX-8500

POWER SUPPLY OVERVIEW

Figure 2-14 shows a block diagram of the C204 PSB/PSE board.
CN1
L
Power
Switch.
N
AC Inlet
+37 V
Switching
Line #1
AC Source
+37 V
Switching
Line #2


General:
The power supply board converts AC input voltage to the DC voltages required to operate the printer. The
AC voltage is input to the AC inlet, and sent to the C204 PSB/PSE board via the power switch and a fuse.
The two main switching regulator circuits consist of two blocks, +37 V switching lines #1 and #2. Switching
line #1 converts AC voltage to the +37 VDC required for the printhead drive coils. Switching line #2 converts
AC voltage to the +37 VDC required to drive the printer mechanism (motors, solenoid, etc.) and the +5 VDC
required for the regulator circuit (See Table 2-3).


37 V line #1:
+37 VDC is sent to two separate pin groups; printhead pins 1, 2, 7, 9, 10, 11, 12, 15, and 17 form one group;
the other group consists of printhead pins 3, 4, 5, 6, 8, 13, 14, 16 and 18.


37 V line #2:
+37 VDC is supplied to the motors and plunger, and to the +5 VDC regulator circuit and its output.
+5 VDC is supplied to the main logic circuit.
2-14
Surge Cut
(at Power On)
Fuse
Input Filter Rectifier
Circuit Circuit
T1
Smoothing
Circuit
Power Down
PC101 Control
Constant
Voltage
PC102
Control
Over Voltage
Protection
PC1
T2
+5 V Regulator
Smoothing
Circuit
Constant
Current Limit
Voltage
PC201 Monitoring
Control
Figure 2-14. Power Supply Board Block Diagram
Smoothing
Circuit
Over Current
Protection
GP
Current Limit
Monitoring
+5 V Regulator
Circuit
Overcurrent
Protection
GL
Abnormal
Current
(VP1/VP2)
Monitoring
GP
+37 V
(VP1/VP2)
CN3
GP1 GP1
GP2 GP2
CL
PD
DRERR
SD
CN4
VP3 Down
Monitoring
+5 V
GL
+37 V
(VP3)
CN2
GP3
GP3
CN5
Fan Driver
FANDR