Service manual
Table Of Contents
- COVER
- CAUTION
- Safety precautions
- CONTENTS
- 1-1 Specifications
- 1-2 Handling Precautions
- 1-3 Installation
- 1-4 Maintenance mode
- 1-5 Trouble Shooting
- 1-5-1 Paper misfeed detection
- 1-5-2 Self-diagnosis
- 1-5-3 Image formation problems
- (1) No image appears (entirely white).
- (2) No image appears (entirely black).
- (3) Image is too light.
- (4) Background is visible.
- (5) A white line appears longitudinally.
- (6) A black line appears longitudinally.
- (7) A black line appears laterally.
- (8) One side of the copy image is darker than the other.
- (9) Black dots appear on the image.
- (10)Image is blurred.
- (11)The leading edge of the image is consistently misaligned with the original.
- (12)The leading edge of the image is sporadically misaligned with the original.
- (13)Paper creases.
- (14)Offset occurs.
- (15)Image is partly missing.
- (16)Fixing is poor.
- (17)Image is out of focus.
- (18)Image center does not align with the original center.
- (19)Image is not square.
- (20)Image contrast is low (carrier scattering).
- 1-5-4 Electrical problems
- (1) The machine does not operate when the main switch is turned on
- (2) The drive motor does not operate when (C200)
- (3) The scanner motor does not operate.
- (4) The toner feed motor does not operate
- (5) Cooling fan motor 1 does not operate
- (6) Cooling fan motor 2 does not operate
- (7) Cooling fan motor 3 does not operate
- (8) The drawer motor does not operate
- (9) The registration clutch does not operate
- (10) The upper paper feed clutch does not operate
- (11) The lower paper clutch does not operate
- (12) Paper feed clutch (ST) 1 does not operate
- (13) Paper feed clutch (ST) 2 does not operate
- (14) The bypass paper feed clutch does not operate
- (15) The cleaning lamp does not turn on
- (16) The exposure lamp does not turn on
- (17) The exposure lamp does not turn off
- (18) The fixing heater does not turn on (C610)
- (19) The fixing heater does not turn off
- (20) Main charging is not performed
- (21) Transfer charging is not performed
- (22) No developing bias is output
- (23) The original size is not detected
- (24) The original size is not detected correctly
- (25) The message requesting papaer to be loaded is shown when paper is present
- (26) The message requesting papaer to be loaded is shown when paper is present in the upper drawer
- (27) The message requesting papaer to be loaded is shown when paper is present in the lower drawer
- (28) The size of paper in the upper drawer is not displayed correctly
- (28) The size of paper in the upper drawer is not displayed correctly
- (29) The size of paper in the lower drawer is not displayed correctly
- (30) The printing width of the paper on the bypass is not detected correctly
- (31) A paper jam in the paper feed, paper conveying or fixing section is indicated when the main switch is turned on
- (32) The message requesting covers to be closed is displayed when the front cover, paper conveying unit and lower drawer left
- (33) Others
- 1-5-5 Mechanical problems
- 1-6 Assembly and disassembly
- 1-6-1 Precautions for assembly and disassembly
- 1-6-2 Paper feed section
- (1) Detaching and refitting the upper and lower paper feed pulleys
- (2) Detaching and refitting the bypass paper feed pulley
- (3) Detaching and refitting the left registration cleaner assembly
- (4) Detaching and refitting the right registration cleaner assembly
- (5) Detaching and refitting the bypass paper width switch
- (6) Adjustment after roller and clutch replacement
- 1-6-3 Optical section
- (1) Detaching and refitting the exposure lamp
- (2) Detaching and refitting the scanner wires
- (3) Detaching and refitting the laser scanner unit
- (4) Adjusting the skew and vertical shifting of the laser scanner unit
- (5) Detaching and refitting the ISU (reference)
- (6) Adjusting the position of the ISU (reference)
- (7) Adjusting the longitudinal squareness (reference)
- (8) Adjusting magnification of the scanner in the main scanning direction
- (9) Adjusting magnification of the scanner in the auxiliary scanning direction
- (10) Adjusting the scanner leading edge registration
- (11)Adjusting the scanner center line
- (12) Adjusting the margins for scanning an original on the contact glass
- 1-6-4 Main charging section
- 1-6-5 Drum section
- 1-6-6 Developing section
- 1-6-7 Transfer section
- 1-6-8 Cleaning section
- 1-6-9 Fixing section
- 1-7 Requirements on PCB Replacement
- 2-1 Electrical Parts Layout
- 2-2 Electrical parts layout
- 2-3 Operation of the PCBs
- 2-4 Appendixes
2AV/X
2-3-1
2-3
2-3-1 Power source PCB
24 V DC
output
circuit
IC2
Noise
filter
circuit
12 V DC
output circuit
IC3
5.1 V DC output
circuit IC4
3.3 V DC
output circuit
IC5
Overvoltage
detection circuit
Phase
control
circuit
Switching
regulator
circuit IC1
Zero-cross
detection circuit
PC1
D9
C29,30
C32
24 V DC
12 V DC
5.1 V DC
3.3 V DC
GND
GND
GND
GND
HEATER REM
PC2
C14
C34
D1
AC input
Q1
T1
Rectifier circuit
Power source PCB
PC3
PT1
HEATER COMMON
TR1
5 V DC
Fixing heater control circuit
C37,91
C43
+
Figure 2-3-1 Power source PCB block diagram
The power source PCB (PSPCB) is a switching regulator that converts an AC input to generate 24 V DC, 5.1 V DC, 3.3 V DC
and 12 V DC. It includes a noise filter circuit, a rectifier circuit, a switching regulator circuit, a 24 V DC output circuit, a 5 V DC
output circuit, a 3.3 V DC output circuit, a 12 V DC output circuit, a fixing heater control circuit and a phase control circuit.
The noise filter circuit consists mainly of a line filter and capacitors. It reduces external noise from the AC input and prevents
switching noise generated by the power source PCB from leaving the machine.
The rectifier circuit full-wave rectifies the AC input that has passed through the noise filter circuit using the diode bridge D1.
The smoothing capacitor C14 smoothes out the pulsed current from the diode bridge.
In the switching control circuit, PWM controller IC1 turns the power MOSFET Q1 on and off to switch the current induced in
the primary coil of the transformer T1.
The 24 V DC output circuit smoothes the current induced in the secondary coil of the transformer T1 via diode D9 and
smoothing capacitors C29 and C30, and outputs a stable 24 V DC by the function of the shunt regulator IC2. It also monitors
the 24 V DC output status, which is fed back to PWM controller IC1 in the switching control circuit via photocoupler PC2.
PWM controller IC1 controls the switching duty width of the power MOSFET Q1 based on the output voltage status,
producing a stable 24 V DC output.
The 5.1 V DC output circuit consists of a step-down chopper circuit that uses IC4 as the control IC. It outputs a stable 5.1 V
DC.
The 3.3 V DC output circuit converts the 5 V DC from the 5 V DC output circuit to a stable 3.3 V DC by means of the 4-pin
regulator IC5.
The 12 V DC output circuit converts the 24 V DC from the 24 V DC output circuit to a stable 12 V DC by means of the 4-pin
regulator IC3.
The phase control circuit and zero-cross detection circuit prevent flicker problems. These circuits modify the fixing heater on
signal from the main PCB (MPCB) to prevent abrupt variations in current when turning the fixing heaters on and off, and
convey the signal to the fixing heater control circuit.
The fixing heater control circuit is controlled by the fixing heater on signal modified at the phase control circuit. The
phototriac PT1 turns on when the fixing heater on signal goes low. When the phototriac PT1 is turned on, current flows
through the triac TR1 to turn the fixing heaters on.