Samsung ML-1740 Service Manual

SERVICE

LASER PRINTER ML-1740

Manual

LASER PRINTER CONTENTS

1. Precautions

2. Reference Information

3. Specifications

4. Summary of product

5. Disassembly and Reassembly

6. Alignment and Adjustments

7. Troubleshooting

8. Exploded Views and Parts List

9. Block Diagram

10. Connection Diagram

Printed in Korea.

VERSION NO. : 1.00 CODE : JC-0117A

This service manual is also provided on the web, the ITSELF system f Samsung Electronics Co., Ltd.

http://itself.sec.samsung.co.kr

ELECTRONICS

2003. 12

1-1

Samsung Electronics

Precautions

Service Manual

1. Precautions

The cautions in the below are items needed to keep in mind when maintaining and servicing. Please read carefully and keep the contents in mind to prevent accidents while servicing and to prevent that the machine gets damage.

1.1 Warning for safety.

(1) Request the service by qualified service person. The service for this machine must be performed by a service person who took the additional education of this field. It is dangerous if unqualified service person or user tries to fix the machine.

(2) Do not rebuild it discretionary. Do not attach or change pats discretionary. Do not dissemble, fix, and rebuilt it. If do, printer will abnormally work and electric shock or a fire can be occurred.

(3) Laser Safety Statement The Printer is certified in the U.S. to conform to the requirements of DHHS 21 CFR, chapter 1 Subchapter J for Class 1(1) laser products, and elsewhere, is certified as a Class I laser product conforming to the requirements of IEC 825. Class I laser products are not considered to be hazardous. The laser system and printer are designed so there is never any human access to laser radiation above a Class I level during normal operation, user maintenance, or prescribed service condition.

Warning >> Never operate or service the printer with the protective cover removed from Laser/Scanner assembly. The reflected

beam, although invisible, can damage your eyes. When using this product, these basic safety precautions should always be followed to reduce risk of fire, electric shock, and injury to persons.

CAUTION - INVISIBLE LASER RADIATION

WHEN THIS COVER OPEN. DO NOT OPEN THIS COVER.

VORSICHT - UNSICHTBARE LASERSTRAHLUNG,

WENN ABDECKUNG GE FFNET. NICHT DEM STRAHL AUSSETZEN.

ATTENTION - RAYONNEMENT LASER INVISIBLE EN CAS

D OUVERTURE. EXPOSITION DANGEREUSE AU FAISCEAU.

ATTENZIONE - RADIAZIONE LASER INVISIBILE IN CASO DI

APERTURA. EVITARE LESPOSIZIONE AL FASCIO.

PRECAUCION - RADIACION LASER IVISIBLE CUANDO SE ABRE.

EVITAR EXPONERSE AL RAYO.

ADVARSEL. - USYNLIG LASERSTR LNING VED BNING, N R

SIKKERHEDSBRYDERE ER UDE AF FUNKTION. UNDG UDSAETTELSE FOR STR LNING.

ADVARSEL. - USYNLIG LASERSTR LNING N R DEKSEL

PNES. STIRR IKKE INN I STR LEN.

UNNG EKSPONERING FOR STR LEN.

VARNING - OSYNLIG LASERSTR LNING N R DENNA DEL

R PPNAD OCH SP RREN R URKOPPLAD.

BETRAKTA EJ STR LEN. STR LEN R FARLIG.

VARO! - AVATTAESSA JA SUOJALUKITUS OHITETTAESSA

OLET ALTTIINA N KYM TT M LLE LASERS TEILYLLE L KATSO S TEESEEN.

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Precautions

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Service Manual

1.2 Caution for safety

1.2.1 Precaution related noxious material

The toner in a printer cartridge contains a chemical material, which might harm human body if it is swallowed. Please keep children out of the toner cartridge.

1.2.2 Precaution related electric shock or fire

It is possible to get electric shock or burn by fire if you don't fallow the instructions of the manual.

(1) Use exact voltage. Please do use an exact voltage and wall socket. If not, a fire or an electric leakage can

be caused.

(2) Use authorized power code. Do use the power code supplied with PRINTER. Afire can be occurred when

over current flows in the power code. (3) Do not insert many codes in an outlet. If do, a fire can be occurred due to flow over current in an outlet. (4) Do not put water or extraneous matter in the PRINTER. Please do not put water, other liquid, pin, clip, etc.

It can cause a fire, electric shock, or malfunction. If it is happened, turn off the power and remove the

power plug from outlet immediately. (5) Do not touch the power plug with wet hand. When servicing, do remove the power plug from outlet. And

do not insert or take off it with wet hand. Electric shock can be occurred. (6) Caution when inserting or taking off the power plug. The power plug has to be inserted completely. If not,

a fire can be caused due to poor contact. When taking off the power plug, do grip the plug and take it off.

If grip the line and pull over, it could be damaged. A fire or electric shock could cause. (7) Management of power code. Do not bend, twist, or bind it and place other materials on it. Also, do not fix

it with staples. If the power code gets damage, a fire or electric shock can be caused. Adamaged power

code must be replaced immediately . Do not repair the damaged part and reuse it. Arepaired part with plas-

tic tape can be occurred a fire or electric shock. Do not spread chemicals on the power code. Do not

spread insecticide on the power code. Afire or electric shock can be occurred due to thinner(weak) cover

of the power code. (8) Check whether the power outlet and the power plug are damaged, pressed, chopped, or blazing fire or

not. When such inferiorities are found, repair it immediately. Do not make it pressed or chopped when

moving the machine. (9) Caution when thundering, and being flash of lightening. It causes a fire or electric shock. Take the power

plug off when thundering. Do not touch cable and device when thundering and being flash of lightening. (10) Do avoid the place where is moisture or has dust. Do not install the printer in where have lots of dust or

around humidifier. A fire can be occurred. Aplug part need to clean well with dried fabric to remove dust. If water drops are dripped on the place covered with dust, a fire can be occurred.

(11) Avoid direct sunlight. Do not install the printer near to window where directly contacts to the sunlight. If

the machine contacts sunlight long time, the machine cannot work properly because inner temperature of the machine is getting higher. A fire can be caused.

(12) Turn off the power and take off the plug when a smoke, strange smell, or sound from the machine. If you

keep using it, a fire can be occurred.

(13) Do not insert steel or metal piece inside/outside of the machine. Do not put steel or metal piece into a

ventilator. An electric shock could be happened.

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Precautions

Service Manual

1.2.3 Precaution related handling the machine.

If you ignore this information, you could get harm and machine could be damaged.

(1) Do not install it on the different levels, or slanted floor.

Please confirm whether it is balanced or not after installation. If it is unbalanced, an accident can be happened due to the machine fell over.

(2) Be careful not to insert a finger or hair in the rotating unit.

Be careful not to insert a finger of hair in the rotating unit (motor, fan, paper feeding part, etc) while the machine is operating. Once it happens, you could harm.

(3) Do not place a pot contains water/chemical or small metals. If those are got into the inner side of machine,

a fire or electric shock can be occurred.

(4) Do not install it in where lots of moisture or dust exists or where raindrop reaches. Afire or electric shock

can be caused.

(5) Do not place a candlelight, burning cigarette, and etc. on the machine. Do not install it near to heater. A

fire can be occurred.

1.2.4 Precaution when assembly/disassembly

When replace parts, do it very carefully. Do memorize the location of each cable before replace parts for reconnecting it afterwards. Do memorize. Please perform the below before replace or disassembly the parts.

(1) Check the contents stored in the memory. All the information will be erased after replace main board. The

information needed to keep has to be written down. (2) Before servicing or replacing electric parts, take off a plug. (3) Take off printer cables and power code connected to printer. (4) Do use formal parts and same standardized goods when

replacing parts.Must check the product name, part code,

rated voltage, rated current, operating temperature, etc. (5) Do not give an over-force when release or tighten up the

plastic parts. (6) Be careful not to drop the small parts such as screws in the

printer. (7) Be careful not to change the location of small parts such as

screws when assembling and disassembling. (8) Do remove dust or foreign matters completely to prevent fire

of tracking, short, or etc. (9) After finished repair, check the assembling state whether it is

same as before the repair or not.

552 mm(21.7 in.)

100 mm

(3.9 in.)

954.6 mm(37.5 in.)

482.6 mm(18.8 in.)

100 mm

(3.9 in.)

100 mm

(3.9 in.)

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Precautions

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Service Manual

1.3 ESD Precautions

Certain semiconductor devices can be easily damaged by static electricity. Such components are commonly called “Electrostatically Sensitive (ES) Devices”, or ESDs. Examples of typical ESDs are: integrated circuits, some field effect transistors, and semiconductor “chip” components. The techniques outlined below should be followed to help reduce the incidence of component damage caused by static electricity.

Caution >>Be sure no power is applied to the chassis or circuit, and observe all other safety precautions.

1. Immediately before handling a semiconductor component or semiconductor-equipped assembly, drain off any electrostatic charge on your body by touching a known earth ground. Alternatively, employ a commercially available wrist strap device, which should be removed for your personal safety reasons prior to applying power to the unit under test.

2. After removing an electrical assembly equipped with ESDs, place the assembly on a conductive surface, such as aluminum or copper foil, or conductive foam, to prevent electrostatic charge buildup in the vicinity of the assembly.

3. Use only a grounded tip soldering iron to solder or desolder ESDs.

4. Use only an “anti-static” solder removal device. Some solder removal devices not classified as “anti-static” can generate electrical charges sufficient to damage ESDs.

5. Do not use Freon-propelled chemicals. When sprayed, these can generate electrical charges sufficient to damage ESDs.

6. Do not remove a replacement ESD from its protective packaging until immediately before installing it. Most replacement ESDs are packaged with all leads shorted together by conductive foam, aluminum foil, or a comparable conductive material.

7. Immediately before removing the protective shorting material from the leads of a replacement ESD, touch the protective material to the chassis or circuit assembly into which the device will be installed.

8. Maintain continuous electrical contact between the ESD and the assembly into which it will be installed, until completely plugged or soldered into the circuit.

9. Minimize bodily motions when handling unpackaged replacement ESDs. Normal motions, such as the brushing together of clothing fabric and lifting one’s foot from a carpeted floor, can generate static electricity sufficient to damage an ESD.

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REFERENCE INFORMATION

Service Manual

2. Reference Information

This chapter describes the reference information for applying this training manual, and it is consisted of the tool list, the abbreviation table, the outline of model, and so on.

2.1 Tool for Troubleshooting

The following tools are recommended for safe and smooth troubleshooting described in this service manual.

DCU(Diagnostic Control Unit)

Standard : Test equipment to diagnose the Laser printer supplied by Samsung Electronics.

Driver

Standard : "-" type, "+" type (M3 long, M3 short, M2 long,

M2 short).

Cotton Swab

Standard : For general home use, for medical ser-vice

Software(Driver) installation CD ROM

Cleaning Equipments a IPA(Isopropyl Alcohol)dry cloth or a soft stuff neutral detergent

T weezers

Standard : For general home use, small type.

DVM(Digital Volt Meter)

Standard : Indicates more than 3 digits.

Electronic Scale

Standard : Equipment to check the weight of consumables(toner cartridge) supplied by Samsung Electronics. (The gram unit can be measured.)

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REFERENCE INFORMATION

Samsung Electronics

Service Manual

2.2 Acronyms and Abbreviations

The table in the below explains abbreviations used in this service manual. The contents of this service manual are declared with abbreviations in many parts. Please refer to the table.

AC Alternating Current ASIC Application Specific Integrated Circuit ASSY assembly BIOS Basic Input Output System CMOS Complementary Metal Oxide

Semiconductor CN connector CON connector CPU Central Processing Unit dB decibel dbA decibelampere dBM decibel milliwatt DC direct current DCU Diagnostic Control Unit DPI Dot Per Inch DRAM Dynamic Random Access Memory DVM Digital Voltmeter ECP Enhanced Capability Port EEPROM Electronically Erasable Programmable

Read Only Memory EMI Electro Magnetic Interference EP electrophotographic EPP Enhanced Parallel Port F/W firmware GDI graphics device interface GND ground HBP Host Based Printing HDD Hard Disk Drive HV high voltage HVPS High Voltage Power Supply I/F interface I/O Input and Output IC integrated circuit IDE Intelligent Drive electronics or Imbedded

Drive Electronics

IEEE Institute of Electrical and Electronics

Engineers. Inc IPA Isopropy Alcohol IPM Images Per Minute LAN local area network lb pound(s) LBP Laser Beam Printer LCD Liquid Crystal Display LED Light Emitting Diode LSU Laser Scanning Unit MB megabyte MHz megahertz NVRAM nonvolatile random access memory OPC Organic Photo Conductor PBA Printed Board Assembly PCL Printer Command Language , Printer

Control Language PDL Page Discription Language PPM Page Per Minute PTL Pre-Transfer Lamp Q-PID Quick Printer Initiating Device Q ty quantity RAM Random Access Memory ROM Read Only Memory SCF Second Cassette Feeder SMPS Switching Mode Power Supply SPGP Samsung Printer Graphic Processor SPL Samsung Printer Language Spool Simultaneous Peripheral Operation Online SW switch sync synchronous or synchronization USB Universal Serial Bus

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REFERENCE INFORMATION

Service Manual

2.3 The Sample Pattern for the Test

The sample pattern shown in below is the standard pattern used in a factory. The contents of the life span and the printing speed are measured with the pattern shown in below. (The picture in the manual is 70% size of the actual A4 size.)

2.3.1 A4 5% Pattern

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Service Manual

2.3.2 A4 2% Pattern

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REFERENCE INFORMATION

Service Manual

2.3.3 A4 IDC Pattern

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Service Manual

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Samsung Electronics

Specifications

Service Manual

3. Specifications

Product specifications are subject to change without notice.See below for product specifications.

3.1 General Specifications

ITEM DESCRIPTION

Print Technology Non-impact Electro-photograpic Printing Developing system Non-Magnetic, Mono-Component Developing System *Print Speed Up to 16 PPM in A4 size, 5% Character pattern

Up to 17 PPM in A4 size, 5% Character pattern Resolution ML-1740 : Up to 600 x 600 DPI effective output Source of Light Laser diode (LSU : Laser Scanner Unit) Warm-Up Time Power-on boot : 30 seconds or less First Print Out Time 12 seconds (Ready to 1st page out) Media Size 76 X 127 (3” X 5”) mm to 216 X 356 (8.5” X 14”)mm Media Thickness 16 ~ 24 lb Dimension(W X D X H) 361.2 X 372.3 X 197.7(mm) Weight Net : 7 Kg /15.4 lb

Gross : 9.5 Kg (Max.) **Acoustic Noise Stand by : Less than 35 dB

Printing : Less than 50 dB Power save mode Available

Toner save mode Available Duty Cycle Monthly : 15,000 pages maximum Periodic Replacing Parts

(2)

Pick Up Roller : Up to 60,000 Sheets

Feed Roller : Up to 60,000 Sheets

Transfer Roller : Up to 60,000 Sheets

Fuser Assembly : Up to 60,000 Sheets

* Print speed will be affected by Operating system used, computing performance, application software, con-

necting method, media type, media size and job complexity.

** Sound Pressure Level, ISO 7779

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Specifications

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Service Manual

3.3 Electrical Specification

3.2 Controller Specification

ITEM

DESCRIPTION

ML-1710P

Processor(CPU) Samsung Jupiter3 90MHz OS Compatibility

(1)

Windows 98/NT4.0/2000/Me/XP, Various Linux OS including Red Hat, Caldera, Debian, Mandrake, Slackware, SuSE and Turbo Linux

Memory FLASH ROM(PROGRAM) : 0.5MB flash

8 MB (ML-1710P)

EEPROM(NVRAM) : 512 byte Emulation SPL(Samsung Printer Language) Interface USB 1.1

- 12 Mbps 1 port

Parallel : IEEE 1284

- Modes supported : Compatible,Nibble,Byte,ECP External Network Adaptor(Optional)

Interface switching Automatic Interface time-out 5min(Max.) Font Windows Font

ITEM DESCRIPTION

Input Voltage Nominal input voltage 127 VAC

Input voltage range 90~132 VAC Nominal frequency 50/60 Hz Frequency tolerance +3Hz

Power Consumption Printing : 280W Avg or less Power Save : 10W Avg or less

3-4 Environmental Range

ITEM OPERA TING STORAGE

Temperature 10~32 oC(50-90 oF) -20~40 oC (-4~104 oF) Humidity 20~80%RH 10~80%RH

(1)

The SPL series model is USB exclusive use, so it supports the environment beyond the WIN 98.

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Specifications

Service Manual

• Input capacity

Cassette: 250 sheets Manual : 1 sheet

• Output capacity

Face Down : 50 sheets(20lb) Face Up : 1 sheet(OHP, Lavbel, Cut Sheet, Envelope)

2-Paper Handling Specifications

Please refer to "Paper Specifications" on user guide

• Input Paper Size

3.5 TONER Cartridge (Developer)

ITEM DESCRIPTION REMARK

Life span Starter: Up to 1,000 sheets IDC 5% pattern

Running : Up to 3,000 sheets Developing Non-magnetic Mono Conponent Contact Developing Charging Conductive Roller Charging Toner checking sensor Not Available Ozone 0.1PPM or less 8 hours Style Single cartridge

P APER DIMENSIONS WEIGHT

A4 210 X 297 mm 60 to 90 g/m2 bond(16 to 24 lb) Letter 216 X 279(8.5 X 11") Legal(Legal14") 216 X 356(8.5 X14") JIS B5 182 X257mm (7.2 X 10") Folio(Legal13") 216 X 330mm (8.5 X 13")

Minimum size (Custom) 76 X 127mm (3 X 5") 60 to 163 g/m2bond(16 to 43 lb) Maximum size (Custom) 216 X 356mm (8.5 X 14") Transparency(OHP) Same minimum and maximum Thickness: Label paper sizes as listed above 0.10 X 0.14 mm (0.0039 X 0.0055")

Envelopes Up to 90 g/m2 bond(16 to 24 lb)

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Specifications

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Service Manual

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SUMMARY OF PRODUCT

Service Manual

4. Summary of Product

This chapter describes the functions and operating principal of the main component.

4.1 Printer Components

4.1.1 Front View

Output Support

Top output tray (Face down)

Control Panel

Power switch

Paper level indicator

Tray

Manual Feeder

Manual Feeder guide

Front Cover

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Service Manual

4.1.2 Rear View

Rear output tray (Face up)

Power receptacle

Parallel port

USB port

4.1.3 Inside View

Toner cartridge

Front Cover

LED Description

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SUMMARY OF PRODUCT

Service Manual

4.1.3 Control Panel

1) On Line/Error and Toner Save LEDs

If the On Line/Error lights green, the printer is ready to print. If the On Line/Error lights red, the printer is experiencing an error, such as jammed paper,

the open cover or the empty toner cartridge. If you press the Cancel button while the printer is receiving data, the On Line/Error LED blinks red to cancel printing.

In Manual Feed mode, if there is no paper in the Manual Feeder, the On Line/Error LED blinks red. Load paper into the Manual Feeder and the LED stops blinking.

If the printer is receiving data, the On Line/Error LED slowly blinks green. If the printer is printing the received data, the On Line/Error LED blinks green fast.

If you press the Cancel button in Ready mode, this LED is on and the Toner Save mode is enabled. If you press this button once again, this LED is off and the Toner Save mode is disabled.

If the On Line/Error and Toner Save LEDs blink, your system has some problems. To solve the problem.

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Service Manual

2) Cancel button

Printing demo page In Ready mode, press and hold this button for about 2 seconds until

all LEDs blink slowly, and release.

Printing configuration sheet In Ready mode, press and hold this button for about 6 seconds until

all LEDs blink fast, and release.

Manual feeding Press this button each time you load a sheet of paper in the manual

feeder, when you select Manual Feed for Source from your software application.

Cleaning inside printer In Ready mode, press and hold this button for about 10 seconds

until all LEDs turn on, and release. After cleaning the printer, one cleaning sheet prints.

Canceling print job Press this button during printing. The On Line/Error LED blinks while

the print job is cleared from both the printer and the computer, and then return to Ready mode. This may take some time depending on the size of the print job. In Manual Feed mode, you can’t cancel the print job by pressing this button.

Toner Save mode on/off In Ready mode, press this button to turn the Toner Save mode on or

off.

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SUMMARY OF PRODUCT

Service Manual

4.2 System Layout

PTL

TR FR

OPC

L S U

Fuser

Toner Cartridge

Cassette

Manual Feeder

Transfer Roller

PTL(Per-Tramsfer-Lamp)

6 7

Fuser

LSU(Laser Scan Unit)

Toner Cartridge

MP Sensor

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Service Manual

4.2.1 Feeding Part

There are the universal cassette, which loads papers, and the manual feeder, which supplies paper one by one. The cassette has the function pad which separates paper one by one, and it has the sensor function to check the existence of the loading paper.

- Feeding Method: Universal Cassette Type

- Feeding Standard: Center Loading

- Feeding Capacity: Cassette-250 sheets (75g/m©˜, 20lb paper standard) Manual 1 sheet (Paper, OHP, Envelop, etc.)

- Paper detecting sensor: Photo sensor

- Paper size sensor: None

4.2.2 Transfer Ass’y

It is consisted of the PTL (pre-transfer lamp) and the Transfer Roller. The PTL sends a light to the OPC drum, makes the current on the drum surface to low, and improves the transfer efficiency. The transfer roller delivers the toner of the OPC drum to the paper.

- The life span: Print over 60,000 sheets (in 15~30°C)

4.2.3 Driver Ass’y

It is a power delivery unit by gearing. By driving the motor, it supplies the power to the feeding unit, the fusing unit, and the distributing unit.

4.2.4 Fixing Part(Fuser)

- The fuser is consisted of the Heat Lamp, Heat Roller, Pressure Roller, Thermistor, and Thermostat. It adheres the toner to the paper with a pressure and a heat to complete the printing job.

- There are two methods, the existing method which use the Heat Lamp and the Q-PID which is developed by Samsung.

110V : Heat Lamp type Fuser 220V : Heat Lamp type or Q-PID type Fuser

4.2.4.1 Temperature-Intercepting Device (Thermostat)

The thermostat is the temperature-intercepting device, which cuts off the power for preventing an overheating or a fire when the heat lamp or the heat coil of the heat roller is overheated.

4.2.4.2 Temperature Detecting Sensor (Thermistor)

The Thermistor detects the surface temperature of the heat roller, and it maintains the regular temperature of the heat roller by responding to the information of the temperature.

4.2.4.3 Heat Roller

The heat roller transfers the temperature from the heat lamp or heat coil to the surface to heat the paper which passes the surface. The melted toner cannot stain the heat roller coated with Teflon. The heating elements are heat lamp and heat coil. For this product, Q-PID method with the heat coil is applied.

4.2.4.4 Pressure roller

The pressure roller mounted right under the heat roller is made of the silicon resin, and the surface of the roller is coated with Teflon to fuse the toner on the paper when paper passes between the heat roller and the pressure roller.

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SUMMARY OF PRODUCT

Service Manual

4.2.4.5 Safety Relevant Facts

• Protecting device when overheating

- 1st protecting device: H/W cuts off when detecting an overheating

- 2nd protecting device: S/W cuts off when detecting an overheating

- 3rd protecting device: Thermostat cuts off the power

• Safety device

- The power of the fuser is cut off when the front cover is open.

- The overheating safety device for customer

- Maintains the surface temperature of the Fuser Cover under 80°C and attach the caution label inside of the rear cover where customer can find easily.

4.2.5 LSU (Laser Scanner Unit)

The LSU unit is controlled by the video controller. It scans the video data received from video controller with laser beam by using the rotation principal of the polygon mirror to create the latent image on the OPC drum. It is the core part of LBP. The OPC drum rotates as the same speed as the paper feeding speed. It creates the /HS YNC signal and sends it to the engine when the laser bean of the LSU reaches the end of the polygon mirror, and the engine detects the /HS YNC signal to arrange the vertical line of the image on the paper. After detecting the /HS YNC signal, the image data is sent to the LSU to arrange the its left margin on the paper. The one side of the polygon mirror is one line for scanning.

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Service Manual

4.2.6 Toner Cartridge

By using the electronic photo process, it creates a visual image. In the toner cartridge, the OPC unit and the developer unit are in a body. The OPC unit has OPC drum and charging roller, and the developer unit has toner, toner cartridge, supply roller, developing roller, and blade (Doctor blade)

- Developing Method: Non magnetic 1 element contacting method

- Toner: Non magnetic 1 element shatter type toner

- The life span of toner: 3,000 sheets (IDC Pattern/A4 standard)

- Toner remaining amount detecting sensor: None

- OPC Cleaning: Collect the toner by using electric static + FILM OPC

- Management of disusable toner: Collect the toner by using electric static (Clenerless Type- No disusable toner)

- OPC Drum protecting Shutter: None

- Classifying device for toner cartridge: ID is classified by interruption of the frame channel.

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SUMMARY OF PRODUCT

Service Manual

4.3 Main PBA(SPL Model)

The Engine Board and the Controller Board are in one united board, and it is consisted of CPU part and print part in functional aspect. The CPU is functioned as the bus control, I/O handling, drivers, and PC interface. The main board sends the Current Image dlml Video data to the LSU and manages the conduct of Electrophotography for printing. It is consisted of the circuits of the motor (paper feed, pass) driving, clutch driving, pre-transfer lamp driving, current driving, and fan driving. The signals from the paper feed jam sensor and paper empty sensor are directly inputted to the main board.

ASIC

SDRAM

FLASH

MEMORY

MOTOR DRIVER IC

BUFFER

VIDEO CLK

14.7456MHz

USB CONN COMP ARATOR IC

MAIN CLK

10MHz

CLOCK

GENERA TOR IC

P ARELLEL

CONN

U32

U13 CN7CN8

U24

CN3

CN10

CN6

CN9

OSCI

U27

U16

U26

CN5

OSC2

CN2(DCU PORT) U25U20 U31

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Service Manual

4.3.1 ASIC (Jupiter )

The Jupiter (16Bit RISC Processor), which is the executive controller to operate the printer function, is in use, and the each operation block is driven by system program of the flash memory. The whole system is controlled by driving operation block.

•Main function block

• Completely Integrated System for Embedded Applications,

• 16 Bit Risc Architecture, Efficient and Powerful ARM7TDMI CPU

• LSU Interface Module for Interfacing PVC or HPVC with LSU

• 2 Channel General Purpose DMA Controller for High Speed I/O

• Dual Memory Bus Architecture

• Operating frequency : 80MHz

• Operating power : 3.3V

• Power on reset time : under 6.6ms

4.3.2 Flash Memory

It stores the system program and downloads the system program through the PC interface.

• Capacity : 0.5M Byte

• Access Time : 70 nsec

4.3.3 SDRAM

It is used as a swath buffer, system working memory area, etc. while printing.

• Capacity :

•

Access Time : 60 nsec

4.3.4 Sensor input circuit

1) Paper Empty Sensing

The Paper empty sensor (Photo Interrupter) on the engine board informs the state of paper to CPU whether it is empty or not with operation of the actuator. When cassette is empty, it detects the fact by reading the D0 Bit of CPU, and then informs the fact by selecting the second LED(yellow) among the panel LEDs.

2) MP Sensing

By operation of Actuator on the frame, the MP Sensor (Photo Interrupter) on the engine board informs the state of paper to CPU whether it is empty or not. It reads the D0 Bit of CPU for recognizing paper in MP, and paper is fed from MP if there is.

ML-1740 8 M byte

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SUMMARY OF PRODUCT

Service Manual

3) Paper Feeding, Toner Cartridge Sensing

When paper passes the actuator (feed sensor part), it detects the signal of Photo interrupter, informs the paper feeding state to CPU, and then sprays the image data after certain time. If it doesn't detect the feed sensor within 1 sec. after paper is fed, paper Jam0 is occurred (Red and Yellow will be turned on among the OP panel LEDs), and the fact whether the developer is inserted or not is detected with the same principle. After the developer is mounted, the actuator is operated. The signal from the photo interrupter is detected when it is passing the actuator of the sensor part. That is the developer ID sensing.

4) Paper Exit Sensing

It detects paper state whether paper gets out from the set with operation of exit sensor on the engine board and actuator on the frame. Paper detects the on/off time of exit sensor , and the normal operation or jam information is informed to the CPU. The paper JAM2 is informed. (Red, Yellow LED will be turned on among the OP panel LEDs)

5) Cover Open Sensing

The Cover open sensor is located on the front cover. After the front cover is opened, +24V (DC fan, solenoid, main motor, polygon motor part of LSU, HVPS), which is supplied to the each unit, is cut off. The cover-open sensing is operated by the D0 bit of CPU, and the developer ID sensing is operated. In this case, the red LED among OP panel LEDs will be ON for informing the facts to user.

6) DC FAN / SOLENOID Driving

It is driven by transistor and controlled by D6 bit of CPU. When it is high, the fan is driving by turning on the TR, and it is off when the sleep mode is selected. There are two solenoids, and they are driven by paper pick-up and MP signal. Its driving time is 300ms. The diode protects the driving TR from the noise pulse, which is flown when the solenoid is de-energizing.

7) Motor Driving

The motor driving circuit is formed when the Driver IC is selected in the first place. The A3977 (Motor driver IC) is used in this case. But, the resistance Rs value of sensing and the voltage value of the V reference can be changed by motor driving voltage value.

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SUMMARY OF PRODUCT

Samsung Electronics

Service Manual

4.4 SMPS & HVPS

The SMPS supplies the DC power to the system. It takes 110V/220V and outputs the +3.3V, +5V and +24V to supply the power to the main board and ADF board. The HVPS part creates the high voltage of THV/MHV/Supply/Dev and supplies it to the developer part for making the best condition to display the image. The HVPS part takes the 24V and outputs the high voltage for THV/MHV/BIAS, and the outputted high voltage is supplied to the toner, OPC cartridge, and transfer roller.

MAIN PBA CON.

CN3

(FAN CON.)

CN1

(H/L CON.)

F101

250V L2A

EXIT SENSOR

CN4

(PANEL CON.)

MHV

OPC

DEV

SUPPLY

THV

COVER OPEN SWITCH

MANUAL SENSOR

FEED SENSOR

PAPER-EMPTY SENSOR

110V : 125V/8A

220V : 250V T 5A H

110V : 125V/3A

220V : 250V 2A H

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Samsung Electronics

SUMMARY OF PRODUCT

Service Manual

4.4.1 HVPS(High Voltage Power Supply)

1) Transfer High Voltage (THV+)

- Function: It is a voltage to transfer a toner developed on OPC drum to a paper.

- Output voltage: Maximum +5.0KV ±5% (Duty changeable, unload)

- 1.0KV ±15%(When cleaning, 200MOhm)

- Error: If THV (+) doesn't output, a ghost status (same character is printed after one cycle (76mm) of OPC) with a low density occurs due to a toner on OPC drum cannot normally transfer to a paper.

2) Charge Voltage (MHV)

- Function: It is a voltage to charge entire surface of OPC with -900V ~ -1000V.

- Output voltage: -1.3KV ~ 1.8KV DC ±50V

- Error: If MHV doesn't output, a black paper is printed out because toner on developing roller moves to OPC drum due to the surface of OPC is not charged.

3)Cleaning Voltage (THV-)

- Function: It removes a dirty on a surface by sending a minus toner in a transfer roller to an OPC

drum to recover toners.

- Output Voltage: There is no feedback control, so change range of output is big up to load.

- Error: Toner contamination occurs at a backside of a printed-paper.

4) Developing Voltage (DEV)

- Function: It is a voltage to develop a toner with using a difference of electronic potential on an

exposed part by LSU (Laser Scanning Unit).

* Generally, the electronic potential of exposed OPC is -180V and exposed developer is -350V

when printing, so toner with minus (-) is developed on an exposed part.

- Output voltage: -200V ~ 600V DC ±20V

- Error: 1. If DEV is GND, a density is going significantly down.

2. If DEV is floating due to instable contacting point of terminal, and etc., a density is significantly going up.

5) Supply Voltage(SUP)

- Function: It is a voltage to supply toner to a developing roller.

- Output voltage: : -400V ~ 800V DC °æ 50V(Use ZENER, DEV gear)

- Error: 1. If SUP is GND, a density is dramatically going down.

2. If SUP is floating due to instable contacting point of terminal, and etc., a density is significantly going down as much as it cannot be recognized with eyes.

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