Epson DFX-8500 Service Manual page 69

‰General :
The power supply board converts the AC input voltage to the DC voltages required to operate the printer. The
AC voltage is input to the AC inlet, and is supplied to the C204 PSB/PSE board via the power switch and a
fuse.
Two main switching regulator circuits consist of two blocks, +37 V Lines ½ and 2/2. The one convert the AC
voltage to the +37 VDC specially for the print head coils drive requirement. The other convert the AC voltage
to the +37 VDC for the printer mechanism drive power requirement (motors, solenoid, etc.) and for the
source of +5 V DC regulator circuit requirement (Refer to Table 2-3.).
‰37V line block ½ :
The generated +37 VDC is divided into two destinations; nine of the eighteen printhead pins (pins 1, 2, 7, 9,
10, 11, 12, 15, and 17); the other to nine of the eighteen printhead pins (pins 3, 4, 5, 6, 8, 13, 14, 16 and 18).
‰37V line block 2/2 :
The generated +37 VDC is supplied to the motors and plunger on the printer mechanism, it also supplied to
the +5VDC regulator circuit and it output. +5V DC is supplied to the logic circuit on the main circuit.
‰Cooling fan :
The C204 PSB/PSE board includes a cooling fan that is driven by the +37 VDC. The fan lowers the
temperature of the PSB/PSE board circuit components, and it also lowers the CR motor temperature
because the motor locates on the way of an air exhaust channel of the fan.
Voltage
+37V (VP1-GP1)
+37 V (VP2-GP2)
+37 V (VP3-GP3)
+5 V -GL
VX-GL
Rev. B
Table 2-3. PSB/PSE Board Output DC Voltages
Board
C204 DRV-B
C204 MAIN
C204 DRV
C204 PSB/PSE
C204 MAIN
C204 DRV
C204 DRV-B
C204 PNL
C204 MAIN
C204 DRV
C204 DRV-B
OPERATING PRINCIPLES
Application
Printhead drive ½
Printhead drive 2/2
CR motor drive
PF motor drive
PG motor drive
RF motor drive
HF drive
CR fan drive
Plunger drive
Optional Cutter's motor drive
Cooling fan on the PSB/PSE unit
All logic systems operating voltage
PF motor hold voltage
Plunger hold voltage
PG motor hold voltage
Power for all the sensors
Voltage for power system pull-up. It is switched
by VXCNT signal of the CPU (IC2).
2-15