Brother MFC-9420CN Service Manual page 59

<Layout & Function of the Electrical Parts>
(1) Print PCB (Refer to Fig. 3-29.)
No.
1 Engine Controller
Board PU
(MCTL P.W.B.)
2 Panel ASSY PU
3 LDU P.W.B.
4 PDU P.W.B.
5 Erase Lamp PU
6 I/O Board PU
(IOD P.W.B.)
7 LV Power Supply PU
(DC Power Supply
Unit) (LVPS)
8 HV Power Supply PU
(High Voltage Power
Supply Unit (HVU))
9 Video Controller
PCB
1. Engine Controller
Board PU
(MCTL P.W.B.)
8. HV Power Supply PU
(High Voltage Power
Supply Unit (HVU))
9. Video Controller
PCB
7. LV Power Supply PU
(DC Power Supply Unit) (LVPS)
Name
To control the series of processes of the Machine: Fuser
temperature control, Laser output control, Operator panel
indication, Toner empty sensing control, Error processing
control, Interface control.
To display the machine's operation status and support the
manual input switch.
To control the drive and output of the laser diode to be
included in the optical unit.
To sense the emission of laser diode and also the beam
position to be included in the optical unit.
To discharge the OPC belt by radiating the LED beam onto
the OPC belt to be included in the optical unit.
To relay the signals between the controlled parts and
MCTL P.W.B., and to drive the controlled parts.
To provide the Machine with the power supply for the
machine control.
To provide the machine with the high voltage power supply
that is necessary for the printing process.
To receive the print data from the host computer, convert it
into image data and then send the printing image data to the
MCTL PWB.
Fig. 3-29
3 - 2 7
Function
2. Panel ASSY PU
6. I/O Board PU
(IOD P.W.B.)
5. Erase Lamp PU
3. LDU P.W.B.
4. PDU P.W.B.
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