Samsung SCX 4520, SCX-4521F, SCX4720F Troubleshootin

Troubleshooting

Service Manual

7-1

Samsung Electronics

7. Troubleshooting

7.1 Paper Feed problems – Causes and Solutions

7.1.1 Wrong Print Position

• Description Printing begins when the paper is in the wrong position.

Check and Cause Solution

A defective feed sensor actuator can cause incorrect timing.

Replace the defective actuator

7.1.2 JAM 0

• Description

1. Paper does not exit from the cassette.

2. Jam-0 occurs when the paper feeds into the printer.

PTL

TR FR

Empty Sensor

OPC

L S U

Fuser

Toner Cartridge

EXIT Sensor

Feed

Sensor

MP Sensor

Check and Cause Solution

1. Check the Solenoid by using Tech Mode.

2. Check cassette/MP knock-up plate and springs.

3. Check paper separator pad

4. Check the pick up roller for contamination and correct assembly.

5. If continuous clusters occur, check all rollers between pickup and registration sensor.

6 If the paper feeds into the printer and

Jam 0 occurs, perform Tech Mode to check feed sensor.

1. Replace the solenoid.

2. Repair / replace as required

3 Clean with soft cloth dampened with

IPA (Isopropyl Alcohol) or water. Replace if required.

4. Clean with soft cloth dampened with IPA (Isopropyl Alcohol) or water. Replace if required

5. Ensure all rollers are clean and free to operate correctly.

6. Check the SMPS PBA, Main PBA and all connections. Replace any faulty parts or the

Service Manual

Troubleshooting

7-2

Samsung Electronics

7.1.4 JAM 2

• Description

1. Recording paper is jammed in front of or inside the fuser.

2. Recording paper is stuck in the discharge roller and in the fuser just after passing through the Actuator-Feed.

Check and Cause Solution

1. If the paper is completely fed out of the printer, but Jam 2 occurs: The Exit sensor may be defective.

• After the paper is completely

discharged the Exit sensor actuator should return to its original position to shut the photo-sensor. It may stick open or return only slowly due to contamination be paper debris or foreign objects.

2. If the paper is rolled in the Fuser Roller:

• This occurs when a Guide claw is

broken away, damaged or deformed.

• It occurs when the Spring of a Guide claw is broken or damaged.

• It occurs when the Heat-Roller or Pressure-Roller is seriously contaminated with toner.

1. Check if the exit sensor actuator is defective.

• Check if the actuator exit is deformed (Check if the lever part is deformed).

• Check whether burrs occur in the assembly part of the exit actuator and if the actuator operates smoothly.

• Check if foreign objects or paper debris are preventing the correct operation of the actuator.

2. If the paper is stuck in the fuser : disassemble the fuser and remove the jammed paper, and clean the surface of the pressure roller with dry gauze. Check all ribs, claws and springs.

7.1.3 JAM 1

• Description

1. Recording paper is jammed in front of or inside the fuser.

2. Recording paper is stuck in the discharge roller and in the fuser just after passing through the Actuator-Feed.

Check and Cause Solution

1. If the recording paper is jammed in front of or inside the fuser.

2. If the recording paper is stuck in the discharge roller and the fuser just after passing through the ActuatorFeed, Feed Actuator may be defec tive.

1. Replace the SMPS.

2. Reassemble the Actuator-Feed and Spring-Actuator if the return is bad.

Fuser

EXIT

Sensor

Fuser

EXIT

Sensor

Empty Sensor

L S U

OPC

Toner Cartridge

PTL

Feed

Sensor

TR FR

MP Sensor

L S U

Empty Sensor

OPC

PTL

TR FR

Toner Cartridge

Feed

Sensor

MP Sensor

Troubleshooting

Service Manual

7-3

Samsung Electronics

7.1.5 Multi-Feeding

• Description Multiple sheets of paper are fed at once.

Check and Cause Solution

1. Check that the paper size guides are set correctly (cassette and MPF tray).

2. Solenoid malfunction (the solenoid does not work properly).

3. Friction Pad is contaminated.

4. Paper has a rough surface texture.

1. Adjust paper guides.

2. Replace the solenoids or PBA as appropriate.

3. Clean the friction pad rubber with a soft cloth dampened with IPA (Isopropyl Alcohol) or water.

4. Use paper with a smother surface finish.

7.1.6 Paper rolled in the fuser

• Description Paper rolled around fuser rollers or ‘Concertina’ jam

Check and Cause Solution

1. Contamination of the pressure roller or heat roller.

2. Damaged or deformed ribs, claws or springs.

1. After disassembling the fuser, clean contamination from between the heat roller and the thermistor and also clean contamination from the pressure roller. Clean the surface of the rollers with IPA or water

2. Check for damage or deformation of the print claws and the holder plate claws, and repair or replace as appropriate.

Service Manual

Troubleshooting

7-4

Samsung Electronics

7.1.7 Paper rolled on the OPC Drum

• Description Paper is rolled up in the OPC.

Check and Cause Solution

1. Paper is too thin.

2. The face of paper is curled.

1. Use paper that conforms to the printer specification.

2. Ensure paper is stored properly to prevent curl. Note. To remove paper rolled in the OPC.

• Remove the toner cartridge from the set, taking

care not to touch the green surface. Use the gearwheel at the side to rotate the OPC drum and pull the paper from the cassette.

• Clean fingerprints on the OPC gently with soft

tissue, taking care not to scratch the surface.

7.1.8 Defective ADF

• Description ADF (Automatic document Feeder) does not operate correctly.

Check and Cause Solution

1. Check if the ADF rubber or HOLDER rubber are damaged or contaminated.

2. Check if the ADF Ass'y document sensors (3 paper sensors) are working correctly.

1. Replace the contaminated or damaged part.

2. If you cannot confirm the damaged part with the

Troubleshooting

Service Manual

7-5

Samsung Electronics

7.2 Set Malfunction – Causes and Solutions

7.2.1 LCD Display Defect ( in LCD Display)

• Description

Strange characters are displayed in the LCD Window and OPE Panel buttons do not work.

Check and Cause Solution

1. Clear the memory. (see page 6-18)

2. Check that the OPE HARNESS is connected to the Connection Board correctly.

1. Try again after clearing the memory.

2. If re-connecting the harness does not correct the fault replace the OPE Ass’y and the main Board in sequence.

7.2.2 Defective OPE Keypad

• Description

Pressing keys does not cause the set to respond correctly

Check and Cause Solution

1. Clear the memory. (See page 6-18).

2. Check that there is an audible key click when a key is pressed.

1. Check that the keypad is assembled correctly and the membrane is not damaged, replace the membrane or whole keypad assembly if necessary.

2. If the fault remains replace the OPE Ass’y and the Main board in sequence.

Service Manual

Troubleshooting

7-6

Samsung Electronics

7.2.3 Fuser gear melts due to overheating causing Paper Jam.

• Description

Constant Jam where paper is entering Fuser unit. Fuser rollers do not turn

Check and Cause Solution

1. Check the Heat Lamp, thermostat and thermistor 1. Use EDC Mode to test the fuser. Replace Fuser unit

Replace SMPS or Main PBA as appropriate.

7.2.4 Paper Empty

• Description

Paper Empty is displayed in the LCD panel even when paper is loaded in the cassette.

Check and Cause Solution

1. Deformed paper sensor actuator or faulty sensor.

2. SMPS PBA or Main PBA is defective

3. Faulty cables or connectors.

1. Replace the defective actuator or sensor.

2. Replace the SMPS PBA or MAIN PBAas appropriate.

7.2.5 Paper Empty without indication

• Description

The paper empty message does not appear in the LCD when the paper cassette is empty.

Check and Cause Solution

1. Deformed paper sensor actuator or faulty sensor.

2. SMPS PBA or Main PBA is defective .

1. Replace the defective actuator.

2. Replace the SMPS PBA or MAIN PBAas appropriate

Troubleshooting

Service Manual

7-7

Samsung Electronics

7.2.7 No error message when the cover is open

• Description

The Cover Open message does not appears on the LCD even when the print cover is open.

Check and Cause Solution

1. The ‘Open Cover’ microswitch may be stuck or faulty

2. Check the connector and cables between Switch and main PBA.

1. Use

TECH

mode(“cover sensor test”) to check cover switch operation. Check and replace switch if necessary .

2. Replace the Main Control board or Cover Open S/W as necessary.

7.2.6 Cover Open

• Description

The Cover Open message appears on the LCD even when the print cover is closed.

Check and Cause Solution

1. The ‘Open Cover’ microswitch may be stuck or faulty

2. The tab on the front cover may be damaged or broken

3. Check the connector and cables between Switch and main PBA.

1. Use

TECH

mode(“cover sensor test”) to check cover switch operation. Check and replace switch if necessary .

2. Replace the front cover.

3. Replace the Main Control board or Cover Open S/W as necessary.

Service Manual

Troubleshooting

7-8

Samsung Electronics

7.2.10 Printed Vertical Lines become curved

• Description

When printing, vertical lines are not straight.

Check and Cause Solution

1. Check stability of 24V supply to LSU. 1. 24V stable - Replace LSU. 24V unstable replace SMPS, if the problem persists replace the main PBA.

7.2.8 Defective motor operation

• Description

Main motor is faulty and paper does not feed into the printer, resulting in Jam 0'

Check and Cause Solution

1. The main motor harness or Motor PCB may be faulty. 1. Check the motor harnesses and connectors, replace if defective.. If the problem persists replace the main PBA.

Note Check motor operation using EDC Mode.

7.2.9 No Power

• Description

When system power is turned on the LCD panel does not come on.

Check and Cause Solution

1. Check if the power input and SMPS output are normal.

2. LCD panel does not come on but normal start up

sounds are heard.

3. After replacing SMPS display does not come on and no

start up sounds are heard.

1. Replace the power supply cord or SMPS. Check power fuse and SMPS fuses replace if necessary.

2. Replace the OP panel.

3. Replace the main PBA panel.

Troubleshooting

Service Manual

7-9

Samsung Electronics

7.3 Paper Feed Problems – Causes and Solutions

7.3.1 Wrong Print Position

• Description Printing begins when the paper is in the wrong position.

Digital Printer Digital Printer Digital Printer Digital Printer Digital Printer

Check and Cause Solution

A defective feed sensor actuator can cause incorrect timing.

Replace the defective actuator

7.3.2 Vertical White Line

• Description White vertical voids in the image.

Digital Printer Digital Printer Digital Printer Digital Printer Digital Printer

Check and Cause Solution

1. 1. Contamination of the window or internal lenses of LSU mirror.

2. Foreign object inside the toner cartridge or low toner.

3. Foreign object, contamination or burr on the edge of the toner cartridge window.

4. If the fuser is defective, voids occur periodically at the top of a black image.

5. Contamination of the OPC drum.

6. Depression or deformation of the surface of the transfer roller

1. Clean the LSU window with recommended cleaner (IPA) Clean the window with a clean cotton swab. If dirt is inside the LSU – replace LSU.

2. Replace the toner cartridge.

3. Clean the exposure window.

4. Open the front cover and check the ribs that correspond to the position of the voids. Remove if found.

5. If the problems are not solved, replace the toner cartridge.

6. Replace the transfer roller.

Service Manual

Troubleshooting

7-10

Samsung Electronics

7.3.3 Horizontal Black Bands

• Description

1. Dark or blurry horizontal stripes occur in the printing periodically. (These may occur at regular intervals down the page.)

Digital Printer Digital Printer Digital Printer Digital Printer Digital Printer

Check and Cause Solution

1. Bad contacts on the toner cartridge high voltage terminals.

2. The rollers in the toner cartridge may be contaminated. Charge roller = 37.7 mm Supply roller = 44.9 mm Develop roller = 35.2 mm Transfer roller = 47.1 mm

1. Clean all HV terminals on the cartridge and on the set frame. Ensure all toner or paper dust particles are removed.

2. Clean the right Gear that has relatively small tooth gap on the OPC.

3. If the problem persists replace the toner cartridge.

7.3.4 Black/White Spot

• Description

1. Dark or blurry black spots occur periodically in the printing.

2. White spots occur periodically in the printing.

Digital Printer Digital Printer Digital Printer Digital Printer Digital Printer

Check and Cause Solution

1. If dark or blurry black spots occur periodically, the rollers in the Developer may be contaminated with foreign matte or paper particles. ( Charge roller : 37.7 mm interval

OPC drum : 75.5 mm interval)

2. If faded areas or voids occur in a black image at intervals of 75.5 mm, or black spots occur elsewhere, the OPC drum surface is damaged.

3. If a black image is partially broken, the transfer voltage is abnormal or the transfer roller's life has expired.

1. Print several OPC cleaning Mode Prints and then run the Self-test 2 or 3 times.

2. 75.5 mm repetition: Examine the surface of the OPC drum and carefully clean with a soft, lint free cloth. If unsuccessful replace the cartridge.

37.7mm repetition: Replace the toner cartridge

3. The transfer roller guarantees 60,000 sheets printing. If the roller's life is expired, replace it.

Note. Cleaning the inside of the set to

remove excess toner particles or paper dust will reduce the occurrence of this problem..

Troubleshooting

Service Manual

7-11

Samsung Electronics

7.3.5 Light Image

• Description The printed image is light, with no ghost.

Digital Printer Digital Printer Digital Printer Digital Printer Digital Printer

Check and Cause Solution

1. Toner Save mode enabled

2. Develop roller is contaminated or the toner cartridge is almost empty.

3. Ambient temperature is below than 10°C.

4. Bad contact caused by dirty terminals on the toner cartridge or set.

5. Abnormal output from the HVPS. (Run EDC mode – see sections 6.5.1 and 6.5.3)

1. Ensure the Toner Save mode is off. Check set and driver settings.

2. Replace the toner cartridge and try to print out again.

3. Wait 30 minutes after printer is powered on before you start printing.

4. Clean the cartridge and set contacts. Generally clean dirt from inside the set.

5. Replace the HVPS if the problems are not solved by the above four instructions.

7.3.6 Dark Image or a Black

• Description The printed image is dark.

Digital Printer Digital Printer Digital Printer Digital Printer Digital Printer

Check and Cause Solution

1. No charge voltage in the engine board.

2. Charge voltage fault due to bad contact between toner cartridge and set contacts.

3. VD0 signal of the Main PBA is Low state.

1. Check the state of the connector which connects the engine board and HVPS.

2. Clean the high voltage charge terminals.

Note if 1 and 2 do not resolve the problem

and the problem persists replace the HVPS.

3. Replace the LSU Unit or Main PBA.

+ 23 hidden pages