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OKI MICROLINE 520 Matrix Printer

1. P N 51228401 Gear Line Feed Idle RSPL Both B 2 04 7 P N 56510301 Motor Line Feed Assembly RSPL Both B 2 04 P N 56627201 Cord Connection Line Feed RSPL Both B 2 04 Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 91 OKIDATA Service Guide ML520 521 di Chapter 3 Maintenance amp Disassembly 3 2 22 Reset Spring CAUTION Please read through this entire procedure before performing it Do not press against the vertical extensions of the reset spring at any time during this procedure Firm pressure will release the spring not brute force 1 Perform these procedures 3 2 0145 3 2 0645 and 3 2 17 43 2 Place the right side of the unit over the edge of your work surface You must be able to access the bottom of the unit You will be working underneath and above the reset spring 1 at the same time 3 Reach from underneath the unit and press up at the extension A to free the spring from the claw 4 While pressing up slide the spring out in the direction of Arrow B and remove it P N 50923201 Spring Reset RSPL Both B 2 05 5 Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 92 e iTA Service Guide ML520 521 OKIDAT
2. 1 8 03 RAM 128 Kbyte Total Resident RAM Used as Receive Buffer Receive Buffer Size is selected through the Menu Settings are 64 K 32 K 1 line Print Buffer DLL Buffer Scratch Pad Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 11 OKIDATA Service Guide ML520 521 l Chapter 1 Product Specifications 1 9 CONSUMABLES 1 9 01 Ribbon CAUTION Using a non Okidata ribbon may damage the printhead and void any warranties Material Nylon fabric cartridge type re inking Type Black Ribbon Life On average at 10 characters per inch Utility Mode 4 million characters Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 12 OKIDATA Service Guide ML520 521 i F Chapter 1 Product Specifications 1 10 OPTIONS Cut Sheet Feeders 1 10 01 Cut Sheet Feeders Single Bin The CSF 5000 is a narrow feeder for the Microline 520 Single Bin with envelope capability Paper Width 7 2 to 8 5 18 3 cm to 36 3 cm Paper Length 10 1 to 14 25 6 cm to 35 6 cm Capacity 170 sheets 16 Ib 100 sheets 20 Ib The CSF 5001 is a wide feeder for the Microline 521 Single Bin with envelope capability Paper Width 7 2 to 14 3 18 3 cm to 36 3 cm
3. eed ies daan a a N a ma CO rath amy nD B bit bas byte inetruction 16 bit but weed instruction Checkout it provided when the original excitagion ls selected Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 24 6 Service Guide ML520 521 OKIDATA Chapter 2 Principles of Operation LSI Location 04B MSM79VO35 Detects the output of the two phase sensor on the DC space motor to control the motor drive phase Transmits and receives serial data to and from the printhead based on the dot timing which is derived from the space motor speed Controls the external interface The LSI is connected to the MPU Cochout it provided when the ceiginel excitation is selected Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 25 6 Service Guide ML520 521 OKIDATA Chapter 2 Principles of Operation Electrically Erasable Programmable Read Only Memory EEPROM Location 03C 930846 The EEPROM is a CMOS serial I O type memory EEPROM It is capable of electrically erasing and writing 1 024 bits The EEPROM contains the menu data and the head drive time correction data Write cycle timing WRITE Copyright 1997 Okidata Divisio
4. OKIDATA Service Guide ML520 521 da Chapter 2 Principles of Operation Printhead Temperature If the printhead temperature exceeds 110 degrees Celsius the printer will switch to uni directional print If the temperature exceeds 118 degrees Celsius printing will stop Once the printhead cools printing will resume Two thermistors are used to monitor the printhead temperature One is contained in the printhead The other is in the printhead driver A thermistor in the printhead prevents over heating of the coil during periods of continuous bi directional printing If the temperature of the coil exceeds the pre determined limits the control circuit detects the thermistor signal TSD Another thermistor monitors the temperature of the printhead driver If the temperature of the driver exceeds the pre determined limits the control circuit detects the thermistor signal TSD The voltage of the TSD signal is monitored at the MPU A D port to control the pass number and print method uni directional bi directional at each of seven levels Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 50 C Service Guide ML520 521 OKIDATA Chapter 2 Principles of Operation 2 2 02 Spacing Mechanism The spacing mechanism consists of a carriage shaft mounted parallel to the platen and a carriage fr
5. 1 up and then out to remove it P N 51010301 Plate Left Ground RSPL Both B 2 04 55 Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 86 wi Ww Service Guide ML520 521 OKIDATA Chapter 3 Maintenance amp Disassembly 3 2 17 Right Ground Plate 1 Perform these procedures 3 2 0145 and 3 2 06 43 2 Pull the top tabs 1 of the right ground plate 2 out to free the plate from the claws of the base frame You may have to use a screwdriver to work the plate tabs free 3 Lift the plate and remove it NOTE Installation The plate must be securely seated under the claws P N 51010201 Plate Right Ground RSPL Both B 2 05 4 Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 87 OKIDATA Service Guide ML520 521 J l Chapter 3 Maintenance amp Disassembly 3 2 18 Rear and Cut Sheet Paper Feed Sensor Levers 1 Perform these procedures 3 2 01 jj 3 2 06 i 3 2 07 4A 3 2 1647 and 3 2 20 43 2 Turn the cut sheet continuous feed paper sensor lever 1 until the flag is at the top then work the lever free 3 Remove the lever 4 Turn the rear feed paper sensor lever 2 until the flag is at the top then work the lever free
6. 2 Slightly bow the carriage cable 1 to release it from the claws 2 and the projection on the main frame 3 3 Remove the carriage cable guide 4 4 Remove the carriage cable NOTE Installation The contacts on the cable face up when the cable is positioned on the main frame The cable end with the 45 angled contacts connects to the gear case assembly Do NOT sharply bend the carriage cable You will slightly bow the cable to position it under the claws and over the projection P N 56627301 Cable Carriage Narrow RSPL 520 B 2 07 5 P N 56627302 Cable Carriage Wide RSPL 521 B 2 07 Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 82 i Service Guide ML520 521 OKIDATA Chapter 3 Maintenance amp Disassembly 3 2 13 Space Rack 1 Perform these procedures 3 2 0145 3 2 02 53 3 2 0443 3 2 1045 and 3 2 1143 2 Remove the spring 1 3 Disengage the claws 2 on the both ends of the space rack 3 4 Pull the space rack straight up and remove it NOTE Installation After installing the space rack check the printhead gap adjustment Refer to Section 3 3 of this Service Handbook i Cleaning When cleaning refer to Section 3 4 of this Service Handbook CAUTION Do NOT lubricate the space rack Lubricating the space rack will attract dust If
7. BS BS 7002 Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 8 OKIDATA Service Guide ML520 521 oy Chapter 1 Product Specifications 1 6 OPERATIONAL SPECIFICATIONS 1 6 01 Character Matrix Sizes Table of Print Speed and Character Matrix Mode Near Letter Quality High Speed Draft 80 12cpi 320 12cpi 427 12cpi Matrix H x V 17 x 13 Print Speed at Different CPI for the ML 520 521 520 206 520 240 1 6 02 Characters Per Line Microline 520 Characters Per Line Characters Per Inch 1 6 03 Character Pitches 5 6 8 5 10 12 15 17 1 20 1 6 04 Character Sets Standard ASCII EPSON Character Set amp II IBM Character Set I Il amp All Characters Foreign Character Substitution International Character Sets Code Page 850 860 863 865 and 437 Line Graphics Bar Code Code 39 UPCA UPC E EAN 8 EAN 13 Interleaved 2 of 5 Code 128 A B C Postnet 1 6 05 Emulations NOTE The emulations are co resident Epson FX IBM Proprinter Microline Standard 1 6 06 Fonts Near Letter Quality Courier Utility Gothic High Speed Draft Gothic Bar Code Code 39 UPCA UPC E EAN 8 EAN 13 Interleaved 2 of 5 Code 128 A B C Postnet 1 6 07 Front Panel Switches SELECT Menu Micro Feed Up Down shift Paper Park Line Feed Pitch Select
8. Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 46 OKIDATA Service Guide ML520 521 i vr l Chapter 2 Principles of Operation Line Feed Motor Resistance The resistance of each coil should be approximately 13 ohms Pin number of ii LF Motor Connector pin number CN5 2 3 3h j 4 sh 5 7 4 ae l p alo o H 10 E E i 2i Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 47 OKIDATA Service Guide ML520 521 Chapter 2 Principles of Operation Space Motor Resistance The resistance of each coil should be approximately 5 ohms going Signal Connector pin number SP U SP V SP W PHASE A PHASE B 5V EL Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 48 OKID AT A Service Guide ML520 521 Ff Chapter 2 Principles of Operation Printhead Operation When the printhead is idle the armature is attracted to the permanent magnet The print wires which are attached to each armature are then concealed inside the wire guide When a signal to print a character is received current flows through a coil The magnetic field
9. OPEN OWA O OPEN O CLOSED Peso CLOSED mog O CLOSED Oo ag ee OOPS oo o O Lieu Change lewer Front release gear arm Front release gear shaft Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 55 OKID ATA Service Guide ML520 521 Fi Chapter 2 Principles of Operation Cut Sheet Continuous Sheet Switching Mechanism Top Feed for cut sheet paper When cut sheet paper is used during normal operation or by the Cut Sheet Feeder CSF option place the change lever in the Top Feed position As the platen turns the platen gear causes the idle gear to rotate At this time the rear and front pressure rollers are pressed securely to the platen to feed the cut sheet The cut sheet detection lever enables the cut sheet detection switch which is located on the main control board This places the printer in the cut sheet mode When cut sheet paper is placed between the platen and the paper chute the printer automatically feeds the sheet to the print start position Rear Bottom Feed for continuous feed paper When the continuous feed paper is used either with the rear tractor optional bottom tractor or optional pull tractor place the change lever in the Rear Bottom Feed position When the change lever is placed in this position the reset spring pushes the change
10. for any updates to this material http bpx okidata com Page 21 OKID AT A Service Guide ML520 521 Chapter 2 Principles of Operation Block Diagram a fi 5 i ut OG ie olay SI fH 7 i i raas ir JG E 12 288 WHE a He TEMP TS T AC inpul Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 22 OKIDATA Service Guide ML520 521 Chapter 2 Principles of Operation Program ROM Location 05CA 2701024 This 64k x 16 bit 1Mbit EPROM contains the control program for the printer The MPU executes the instructions contained in this program The Program ROM is assigned to the program memory area of the MPU and instructions are fetched by the PSEN signal of the MPU i i f15 aaa MPU CLOCK aha iT PLEM H D115 Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 23 6 Service Guide ML520 521 OKIDATA Chapter 2 Principles of Operation RAM Location 05CB 5116642 The RAM is CMOS dynamic RAM with 65 536 words x 16 bit configuration It is used as a receive buffer print buffer and work buffer cocks 11 om clocks TI m2 ot ma OOOX we YO mm ho m G ita rn a a boo j
11. America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 42 Ww Service Guide ML520 521 OKIDATA Chapter 2 Principles of Operation 2 1 08 Power Supply Circuit The switching type power supply circuit supplies the 5 vdc 8 vdc 10 VAC and 40 vdc Purpose IC logic levels LED drive voltages Serial interface line voltage comparator IC Serial interface line voltage and the printhead analog circuit Printhead space motor and line feed motor drive voltage Control Board Rectifier 40 v Rectifier 6 v AC IN Ba Transformer Regulation 5 v Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 43 Tw te Service Guide ML520 521 OKIDATA Chapter 2 Principles of Operation 2 2 MECHANICAL OPERATION 2 2 01 Printhead Mechanism The printhead is a spring charged 9 pin printhead It is attached to the carriage which moves parallel to the platen Electrically the printhead is controlled by the main control board via the carriage cable and the Space motor The printhead is composed of the following parts Wire Guide Spring Assembly Wire Armature Spring Yoke Spacer Magnet Assembly Magnet Core Coil Yoke Printed Circuit Board Logic Control Print Driver Analog Sensor
12. OKIDATA Service Guide ML520 521 a Chapter 2 Principles of Operation 2 1 ELECTRICAL OPERATION The printer is comprised of the electrical components listed below Main Control Board Power Supply Assembly Transformer Filter Board Operator Panel Space Motor Line Feed Motor Printhead Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 20 Ww Service Guide ML520 521 OKIDATA Chapter 2 Principles of Operation 2 1 01 Main Control Board The main control board is made up of the microprocessor peripheral circuits drive circuits sensors and interface connectors The power to the main control board is supplied by the transformer assembly through a wire harness The power to other electrical parts line feed motor space motor and printhead is provided by the power supply circuitry through connectors on the main control board Microprocessor MPU Location 04C 67X640 16 bit MPU using CMOS technology The MPU contains a 20 bit address bus a 16 bit data bus The MPU can access 1 Mbyte of program memory and 1 Mbyte of data memory space The microprocessor controls the entire printer by executing the control program through the LSlIs and the driver circuits Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX
13. Only Memory 25 EEPROM 2 1 02 Initialization 26 2 1 03 Parallel Interface Control 27 2 1 04 Print Control 28 seen LSI Printhead Interface 29 eee Gap Adjust Control 30 PEE Print Compensation Control 31 2 1 05 Space and Line Feed SP LF Motor Control 32 ee Line Feed Motor Control 33 mine space Motor Control 34 ee Encoder Disk 35 2 1 06 Operation Panel 36 2 1 07 Alarm Circuit 37 ee Low Motor Drive Voltage Alarm 38 Table of Contents Page eee Head Drive Time 39 ae Print Speed 40 pees Head Overheat Alarm Processing 41 2 1 08 Power Supply Circuit 42 2 2 Mechanical Operation Printhead Mechanism 43 eae Printhead Gap Information 44 e Interconnect Diagram Control Board to Printhead 45 ee Line Feed Motor Resistance 46 eee Space Motor Resistance 47 oe Printhead Operation 48 er Printhead Temperature 49 2 2 02 Spacing Mechanism 50 er Spacing Operation 51 2 2 03 Head Gap Mechanism 52 n Ribbon Drive Operation 53 2 2 05 Line Feed Mechanism 54 eee Cut Sheet Continuous Sheet Switching Mechanism 55 peas Cut Sheet Paper Feed Operation 56 aie Continuous Paper Feed Rear Tractor Mechanism 57 ee Continuous Paper Feed Pull Tractor Mechanism 58 ues Continuous Paper Feed Bottom Tractor Feed 59 Mechanism EA Continuous Paper Feed Push Pull Tractor Mechanism 60 2 2 06 Paper Detection Mechanism 61 2 2 07 Support Protector Mechanism 62 2 2 08 Automatic Paper Load 63 EN Continuous Feed Paper 6
14. a unit which is operating normally If you decide to perform disassembly during this training Okidata recommends that you perform only the disassembly procedures for RSPL items All other procedures are provided to assist you in identifying parts It is not likely that you will perform these procedures while servicing the unit Be sure to read all notes cautions and warnings as they contain important information regarding disassembly assembly Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 70 ae Service Guide ML520 521 OKIDATA Chapter 3 Maintenance amp Disassembly 3 2 01 Preliminary Items 1 Press the AC switch 1 and power off the printer 2 Remove the paper if installed 2 3 Detach the AC power cord 3 4 Detach the interface cable if installed 4 P N 56609701 Cord AC RSPL Both B 2 03 5 P N 56624101 Cord AC 220V ML Series Right Angle Option RSPL Both B 2 03 5 P N 56624401 Cord AC 240V Option RSPL Both B 2 08 P N 70000803 Kit Parallel Interface Option Both B 2 08 Plug n Play Accessory P N 70012801 Kit RS232 C Serial Interface Option Both B 2 08 5 Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 71 i Service
15. changing the head gap by one setting The head gap is modified in 06 mm units for each range setting idie gear Ribbon gear Pranger magnet Amat aa Ribbon drive gear Change gear Gapchange gear Idie gear O Adjust gear r Gap Changer gear a Armature Prange magnat Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 53 FA Service Guide ML520 521 OKIDATA Chapter 2 Principles of Operation Ribbon Drive Operation The ribbon drive mechanism feeds the ribbon in synchronization with the spacing operation The force required to drive the ribbon is obtained from the space motor The ribbon drive mechanism is composed of the items listed below Ribbon Drive Gear Assembly Ribbon Gear This gear is located on the space motor assembly Ribbon Cartridge A continuous loop ribbon with uni directional feed is used Ink is supplied from an ink tank which is built into the ribbon cartridge When the space motor turns the ribbon gear on the spacing motor shaft rotates The rotation is transmitted via a combination of gears from the ribbon drive gear assembly to the drive gear in the ribbon cartridge Although the space motor moves in both the forward and reverse directions during bi directional printing the gears in the ribbon drive assembly maintain uni directional ribbon fee
16. enough dust accumulates on the space rack printing problems will occur P N 50923501 Spring Tension Space Rack RSPL Both B 2 04 P N 53563301 Rack Space Narrow RSPL 520 B 2 04 P N 53563401 Rack Space Wide RSPL 521 B 2 04 4 Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 83 OKID AT A Service Guide ML520 521 Chapter 3 Maintenance amp Disassembly 3 2 14 Roller Holder Backup Assembly 1 Perform these procedures 3 2 01 jj 3 2 02 53 3 2 0443 3 2 1045 and 3 2 11 2 Use a small straight slot screwdriver to disengage the claws of the backup roller holder spring 1 from the carriage frame 2 3 Remove the roller holder backup assembly 3 NOTE The roller holder backup assembly includes the backup roller 4 the backup roller holder 5 and the pin 6 P N 53343201 Assembly Roller Holder Backup Both B 2 07 4 P N 53341701 Roller Back Up RSPL Both B 2 07 4 P N 53341801 Holder Back Up Roller RSPL Both B 2 07 4 P N N A Pin Both B 2 07 lt j P N 50925001 Backup Roller Holder Spring Both B 2 07 4 Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 84 OKIDATA Service Guide ML520 521 Chapter 3 Maintena
17. gear In this position the idle gear is engaged with the bottom tractor unit drive gear and the tractor gear As the platen turns power is transferred from the platen gear to the idle gear to the change gear and then to the push tractor shaft CAUTION The cut sheet continuous sensor lever must be positioned below the BASW sensor The lever should contact the sensor only when the change lever is in the top feed middle setting If the lever is not correctly positioned the ALARM lamp will light and the unit will not automatically load paper or receive data Cut sheet detection switch Main P C_B Platen gear R idi 7 nee Tractor gear Change gear Drive gear Bottom tractor Reset spring Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 56 OKIDATA Service Guide ML520 521 l Chapter 2 Principles of Operation Cut Sheet Paper Feed Operation As the line feed motor rotates power is transferred through the decelerating gears line feed idler gear platen gear to the platen When using cut sheet paper the change lever must be in the TOP position so the platen and pressure rollers can feed the paper This also disengages the push tractor Platen Platen gear LF Idler gear Copyright 1997 Okidata Division of OKI America Inc All rights reser
18. the SNS3 sensor 8 The rear sensor lever must be positioned in the SNS1 sensor 9 The cut sheet continuous sensor lever must be positioned below the BASW sensor 10 The lever should contact the sensor only when the change lever is in the top feed middle setting If the lever is not correctly positioned the ALARM lamp will light and the unit will not automatically load paper or receive data The IC EEPROM is soldered in on the board TER P N 55072401 PCB FJIM w o ROM RSPL Both B 2 03 4 P N 55938301 IC EEPROM BR93CC46A RSPL Both B 2 03 5 Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 77 OKID ATA Service Guide ML520 521 ef Chapter 3 Maintenance amp Disassembly 3 2 08 Power Supply Assembly 1 Perform these procedures 3 2 01 and 3 2 06 43 2 Use a straight slot screwdriver to detach the claws from both sides of the cable clamp 1 3 Remove the cable clamp 2 4 Detach the transformer cable from connector CN3 3 of the control board 4 5 Detach the cable from the connector 5 of the filter board 6 6 Use a straight slot screwdriver to free the transformer from the holding clamp A position the screwdriver in the direction of the arrow 7 twist the screwdriver while pushing the transformer 8 towards the control board 7 Lift and remove
19. 12 7 mm Bottom Feed 0 5 inches 12 7 mm Top Feed 0 5 inches 12 7 mm 1 6 17 Paper Tear Capabilities Forms Tear Off sharp edge on access cover Metal Tear Bar with optional bottom feed tractor unit 1 6 18 Print Method Printhead Type General Information Impact Dot Matrix 9 pin printhead 0134 inch 0 34 millimeter diameter pins Overheat Protection When printhead temperature exceeds 110 degrees Celsius the printer stops bi directional printing Uni directional printing begins If the temperature exceeds 118 degrees Celsius printing stops Printing will resume when the printhead temperature drops below 118 degrees Celsius NOTE Refer to Section Two for more information on printhead operation Printhead Gap Information Three items factor into printhead gap information 1 Printhead Gap Adjustment This is aSERVICE ADJUSTMENT made by a technician It is covered in Section 3 3 of this Service Handbook The Adjustment measures 0 014 0 001 inches 90 35 0 03 mm 2 Printhead Gap Adjustment This is a MENU ITEM in the SET UP Group lt fine tunes the automatic setting of the printhead gap The settings are 0 1 and 1 Use 1 to darken print if output is consistently light Use 1 to lighten print if output is consistently dark 3 Gap Control This is a MENU ITEM in each Paper Feed Group The Groups are REAR FEED BOTTOM FEED and TOP FEED Gap Controls determines how the printhead gap is set The settin
20. 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http obpx okidata com Page 73 OKIDATA Service Guide ML520 521 t Chapter 3 Maintenance amp Disassembly 3 2 04 Gear Case Assembly 1 Perform these procedures 3 2 01 5 and 3 2 0243 2 Use a Straight slot screwdriver to release the four claws 1 of the gear case assembly 2 3 Lift and remove the gear case assembly NOTE Lubrication When lubricating refer to Section 3 5 of this Service Handbook P N 51228501 Gear Case Assembly RSPL Both B 2 07 4 ae Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 74 WIRATA Service Guide ML520 521 OKIDATA Chapter 3 Maintenance amp Disassembly 3 2 05 Pull up Roller Assembly 1 Perform this procedure 3 2 01 5 2 Open the access cover 1 3 Open the cover of the pull up roller assembly 2 4 Press at A while rotating the assembly towards the back of the printer 5 Remove the assembly NOTE Lubrication When lubricating refer to Section 3 5 of this Service Handbook 4 P N 53341501 Roller Pull Up Assembly Narrow RSPL 520 B 2 05 3 P N 53341601 Roller Pull Up Assembly Wide RSPL 521 B 2 0543 Copyright 1997 Okidata D
21. 4 2 2 09 Paper Park 65 3 Maintenance amp Disassembly 3 1 01 General Information 66 3 1 02 Maintenance Tools 67 3 1 03 Maintenance Precautions 68 3 2 Disassembly Assembly Procedures 69 3 2 01 Preliminary Items 70 3 2 02 Printhead Assembly 71 3 2 03 Ribbon Protector 72 3 2 04 Gear Case Assembly 73 3 2 05 Pull up Roller Assembly 74 3 2 06 Upper Cover Access Cover and Sheet Guide 75 Assemblies 3 2 07 Control Board FJIM 76 3 2 08 Power Supply Assembly 77 3 2 09 Operator Panel PCB LEOP 78 0 2 10 PC Connector Table of Contents Page 3 2 11 Space Motor and Roller Guide Assemblies 80 3 2 12 Carriage Cable 81 3 2 13 Space Rack 82 3 2 14 Roller Holder Backup Assembly 83 3 2 15 Guide Rail and Adjust Cam 84 3 2 16 Left Ground Plate 85 3 2 17 Right Ground Plate 86 3 2 18 Rear and Cut Sheet Paper Feed Sensor Levers 87 3 2 19 Platen Assembly 88 3 2 20 Paper Chute Assembly 89 3 2 21 Line Feed Motor Assembly 90 3 2 22 Reset Spring 91 3 2 23 Idle Gear and Change Lever 92 3 2 24 Pressure Spring 93 3 2 29 Carriage Shaft 94 3 2 26 Leaf Spring 95 3 2 2 Bottom Paper Sensor Levers 96 3 2 28 Front Pressure Roller Assembly 97 3 2 29 Tractor Assembly 98 3 2 30 Main Frame 99 3 3 Printer Adjustments 100 3 3 02 Printhead Gap Adjustment 101 3 3 03 Key Combinations 102 3 3 04 Menu Operation 103 ee Me
22. 5 Remove the lever P N 50804902 Lever Sensor RSPL Both B 2 04 A Cut Sheet Continuous P N 50804801 Lever Rear Sensor RSPL Both B 2 04 4 Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 88 al ae Service Guide ML520 521 OKIDATA Chapter 3 Maintenance amp Disassembly 3 2 19 Platen Assembly 1 Perform these procedures 3 2 01 and 3 2 06 53 2 Move the change lever 1 to the bottom feed position to the rear of the printer 3 Push the lock levers 2 in then rotate them towards the front to unlock them from the frame 4 The levers should be vertical 5 Lift the platen assembly 3 straight up and remove it NOTE Installation After installing the platen assembly check the printhead gap adjustment Refer to Section 3 3 of this Service Handbook i Cleaning When cleaning refer to Section 3 4 of this Service Handbook Lubrication When lubricating refer to Section 3 5 of this Service Handbook i P N 50098301 Platen Assembly Narrow RSPL 520 B 2 054 P N 50098302 Platen Assembly Wide RSPL 521 B 2 05 Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 89 i Service Guide ML520 521 OKIDATA Chapter 3 Mai
23. A Chapter 3 Maintenance amp Disassembly 3 2 23 Idle Gear and Change Lever 1 Perform these procedures 3 2 0145 3 2 0645 3 2 0745 3 2 16 i 3 2 17 4A 3 2 19 i 3 2 20 4 and 3 2 2255 2 Remove the idle gear 1 The idle gear is a large narrow gear 3 Release the claw 2 of the change lever 3 The claw is accessed from inside the unit 4 Remove the change lever NOTE Lubrication When lubricating refer to Section 3 5 of this Service Handbook i P N 50805101 Lever Change RSPL Both B 2 05 P N 51228201 Gear Idle RSPL Both B 2 05 5 Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 93 Awa itTe ar A Service Guide ML520 521 OKIDATA Chapter 3 Maintenance amp Disassembly 3 2 24 Pressure Spring 1 Perform these procedures 3 2 01 5 3 2 06 3 3 2 07 3 3 2 16 i 3 2 1747 3 2 19 3 3 2 20 5 3 2 22 i and 3 2 2343 2 Turn the front release gear arm 1 until it is disengaged 3 Remove the release cam 2 This is the medium size thick cam 4 Work the end of the pressure spring 3 free and remove the spring 5 Remove the front release gear arm This arm is long with a serrated edge 6 Remove the switch lever 4 This is the small lever NOTE Installation Install the release cam first Then install one end of the pressure spring into t
24. Control and Thermistor Cooling Fin gt BAL pifi m fean C n E m Cea T a Hg Arrangement of the head pins View from the tip of the printhead Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 44 FA Service Guide ML520 521 OKIDATA Chapter 2 Principles of Operation Printhead Gap Information Three items factor into printhead gap information 1 Printhead Gap Adjustment This is a SERVICE ADJUSTMENT made by a technician It is covered in Section 3 3 of this Service Handbook The Adjustment measures 0 014 0 001 inches 0 35 0 03 mm 2 Printhead Gap Adjust This is a MENU ITEM in the SET UP Group lt fine tunes the automatic setting of the printhead gap The settings are 0 1 and 1 0 is the factory default Use 1 to darken print if output is consistently light Use 1 to lighten print if output is consistently dark 3 Gap Control This is a MENU ITEM in each Paper Feed Group The Groups are REAR FEED BOTTOM FEED and TOP FEED Gap Control determines how the printhead gap is set The settings are listed below Auto Gap Semi Auto Gap 1 2 3 4 5 6 7 8 9 An explanation of each setting follows Auto Gap This is the factory default Automatically determines paper thickness of the first page During single sheet feed each pages thickness is checked whil
25. DATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 41 OKIDATA Service Guide ML520 521 F Chapter 2 Principles of Operation Head Overheat Alarm Processing If the printhead temperature exceeds 110 degrees Celsius the printer will switch to uni directional print If the temperature exceeds 118 degrees Celsius printing will stop Once the printhead cools printing will resume Two thermistors are used to monitor the printhead temperature One is contained in the printhead The other is in the printhead driver A thermistor in the printhead prevents over heating of the coil during periods of continuous bi directional printing If the temperature of the coil exceeds the pre determined limits the control circuit detects the thermistor signal TSD Another thermistor monitors the temperature of the printhead driver If the temperature of the driver exceeds the pre determined limits the control circuit detects the thermistor signal TSD The voltage of the TSD signal is monitored at the MPU A D port to control the pass number and print method uni directional bi directional at each of seven levels Print speed JAA PASS Unid ional 50 7 a 99 PASS Unidtrectiona 37455 Unidirectional E Z PASS Unidirectional E a PASS Unidirectional orint 100 7PASS Bi directional print Mlode 110 C 2 1 CTCI T Copyright 1997 Okidata Division of OKI
26. Guide ML520 521 OKIDATA Chapter 3 Maintenance amp Disassembly 3 2 02 Printhead Assembly 1 Perform this procedure 3 2 01 5 2 Open the access cover 1 3 Lift and remove the ribbon Not shown 4 Pull the head clamp 2 towards the right and then rotate it up to release the printhead 3 5 Pull the printhead straight up to remove it NOTE Installation After installing the printhead check the printhead gap adjustment Refer to Section 3 3 of this Service Handbook P N 52107001 Ribbon Black Consumable Both B 2 10 3 P N 50707401 Clamp Head RSPL Both B 2 07 4 P N 50099501 Assembly Printhead RSPL Both B 2 03 Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 72 OKIDATA Service Guide ML520 521 Fs Chapter 3 Maintenance amp Disassembly 3 2 03 Ribbon Protector CAUTION You MUST use a straight slot screwdriver to release the ribbon protector If you attempt to lift the protector without releasing the tabs the protector will break 1 Perform these procedures 3 2 01 and 3 2 0243 2 Open the pull up roller cover 1 3 Use a straight slot screwdriver to release the extensions 2 from the carriage frame set 3 4 Lift the ribbon protector 4 straight up and remove it P N 53562801 Protector Ribbon RSPL Both B 2 07 4 Copyright
27. Page 1 Service Guide ML520 521 Chapter 0 About This Manual OKIDATA Service Manual ML520 ML521 Dot Matrix Printers Adobe Acrobat printable reference copy of the OKIDATA Service Training Manual 09 17 97 Note This Adobe Acrobat version of the Okidata Service Training Manual was built with the pictures rendered at 300 dpi which is ideal for printing but does not view on most displays well Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Table of Contents Page service Guide ML520 521 0 About This Manual Front Cover 1 Copyright Information 2 1 Product Specifications 1 1 01 General Information 3 1 2 Physical Specifications 4 1 3 Power Requirements 5 1 4 Environmental Conditions 6 1 5 Agency Approvals 7 1 6 Operational Specifications 8 1 7 Paper Specifications 9 1 8 Memory Specifications 10 1 9 Consumables 11 1 10 Options Cut Sheet Feeders 12 een 1 10 02 Pull Tractor Kit 13 sedis 1 10 04 Bottom Push Tractor Kit 14 ee 1 10 05 Serial Interface 15 EEA 1 10 06 Roll Paper Stand 16 ens 1 10 08 OKISmart Typer Utility 17 1 11 Reliability 18 2 Principles of Operation 2 1 Electrical Operation 19 2 1 01 Main Control Board 20 ee Block Diagram 21 een Program ROM 22 oe RAM 23 er LSI 24 anes Electrically Erasable Programmable Read
28. Paper Length 10 1 to 14 25 6 cm to 35 6 cm Capacity 170 sheets 16 Ib 100 sheets 20 Ib Dual Bin P N 70022601 is a narrow feeder for the Microline 520 Dual Bin with envelope capability Paper Width 7 2 to 8 5 18 3 cm to 36 3 cm Paper Length 10 1 to 14 25 6 cm to 35 6 cm Capacity 170 sheets 16 lb 100 sheets 20 Ib P N 70022801 is a wide feeder for the Microline 521 Dual Bin with envelope capability Paper Width 7 2 to 14 3 18 3 cm to 36 3 cm Paper Length 10 1 to 14 25 6 cm to 35 6 cm Capacity 170 sheets 16 lb 100 sheets 20 Ib Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 13 OKIDATA Service Guide ML520 521 l Chapter 1 Product Specifications 1 10 02 Pull Tractor Kit NOTE The Pull Tractor Kit P N 70023001 is a narrow feeder for the Microline 520 The Pull Tractor Kit P N 70023201 is a wide feeder for the Microline 521 Bottom Feed Rear Feed For Push Pull Operation Paper Types Continuous Feed and Labels Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 14 OKIDATA Service Guide ML520 521 l Chapter 1 Product Specifications 1 10 04 Bottom Push Tractor Kit NOTE The Bottom P
29. See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 66 OKID AT A Service Guide ML520 521 Chapter 3 Maintenance amp Disassembly 3 1 01 General Information This section lists the parts replacement adjustment cleaning lubrication and shipping procedures Disassembly should not be performed unless absolutely necessary NEVER perform disassembly on a malfunctioning printer until you have followed the failure analysis procedures in Section Four of this Service Handbook Follow the procedures listed in Adjustments and Service Settings Adjustments may be required when either consumable or parts are replaced Failure to perform these procedures could result in unnecessary service Calls Proper performance of maintenance and cleaning will help to achieve the best possible print quality from the printer Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 67 Ww Service Guide ML520 521 OKIDATA Chapter 3 Maintenance amp Disassembly 3 1 02 Maintenance Tools The following tools are required to service the printer 2 Phillips Screwdriver with magnetic tip Straight slot Screwdriver Needle Nose Pliers 4 Inch Wire Cutters Digital Multimeter Feeler Gauge capable of measuring 014 inches Shop Vacuum Clean soft
30. ame set carriage 4 NOTE Installation After installing the carriage shaft check the printhead gap adjustment Refer to Section 3 3 of this Service Handbook Cleaning When cleaning refer to Section 3 4 of this Service Handbook Lubrication When lubricating refer to Section 3 5 of this Service Handbook P N 50098901 Carriage Frame Set RSPL Both B 2 07 4 P N 50923601 Spring Support Protect Reset RSPL Both B 2 04 4 P N 53067601 Protector Support Assembly RSPL Both B 2 04 P N 53563501 Shaft Carriage Narrow RSPL 520 B 2 04 P N 53563502 Shaft Carriage Wide RSPL 521 B 2 04 5 Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 95 OKID AT A Service Guide ML520 521 wr F Chapter 3 Maintenance amp Disassembly 3 2 26 Leaf Spring 1 Perform these procedures 3 2 01 3 2 0645 3 2 07 5 3 2 16 i j and 3 2 2543 Position the unit so you can access the top and bottom of the leaf spring 1 Start at one end of the spring Use a straight slot screwdriver to release the bottom extension 2 from the claw of the base frame Pull the spring up to release the top of the spring from the upper claw Repeat the above two steps working towards the opposite end of the spring N OF fF W PY Remove the spring P N 50923001 Spring Lea
31. ame which moves along the shaft The carriage frame is driven by a DC servo motor mounted on the Carriage frame ltems included in the spacing mechanism are listed below Space Motor Assembly DC Servo Motor Motor Gear Sensor Encoder Disk Carriage Frame Carriage Shaft Space Rack Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 51 OKID AT A Service Guide ML520 521 Chapter 2 Principles of Operation Spacing Operation The carriage frame which contains the printhead and space motor moves along the carriage shaft parallel to the platen When the space motor rotates the driving force is transmitted to the motor gear As the motor gear rotates the carriage moves along the platen For every revolution of the DC servo motor the carriage frame moves 0 8 inch 20 32 mm As the DC servo motor rotates a slotted disk called the encoder disk rotates with the servo motor and passes through the photosensor The position of the carriage frame can be determined by counting the pulses generated by the photosensors In the same way the rotation of the space motor can be recognized and controlled by measuring the phase relationship and the pulsewidth of the signals generated by the photosensors Print Head Carriage Shaft Slider Guide rail Copyright 1997 Okidata Division of OKI Am
32. and lint free Cloth All Purpose Cleaner Contact Kleen Okidata P N 51802301 Platen Cleaner Machine Grease Machine Oil Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 68 Awd itTe ar A Service Guide ML520 521 OKIDATA Chapter 3 Maintenance amp Disassembly 3 1 03 Maintenance Precautions 1 Do not disassemble the unit if it is operating normally 2 Before starting disassembly and assembly always turn the AC power switch OFF and pull out the AC Oo oo Aa O 9 plug Detach the interface cable if installed Do not remove parts unnecessarily Try to keep disassembly to a minimum Use the recommended maintenance tools When disassembling follow the listed sequence Failure to follow the correct sequence may result in damaged parts Since screws collars and other small parts are easily lost they should be temporarily attached to the Original positions When handling circuit boards use extreme care Integrated circuits microprocessors ROM and RAM can be destroyed by static electricity Do not place printed circuit boards directly on conductive surfaces 10 Follow the recommended procedures when replacing assemblies and units 11 Perform the printhead gap adjustment procedure Refer to Section 3 3 of this Service Handbook when the any of the follow
33. d by switching the rotation direction of the gears Ribbon cartridge i DN A Ribbon drive m gear assembly Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 54 G Service Guide ML520 521 OKIDATA Chapter 2 Principles of Operation 2 2 05 Line Feed Mechanism The line feed operation is accomplished by activating the line feed motor which turns the platen The rotation of the platen is used to feed paper from the selected paper path The components of the paper feed mechanism are listed below Line Feed Motor pulse motor with gears Line Feed Idler Gear Platen Rear Tractor Feed Unit Pressure Roller Change Lever Paper Path Selection Lever The change lever is used to select one of three different paper paths top rear or bottom Paper Clamp Mechanism Moving the change lever between the bottom top and rear positions changes the positions of the front release gear arm and the release cam The movement of the front release gear arm changes the position of the front release gear shaft This causes the front pressure roller to open or close The movement of the release cam causes the rear pressure roller to open or close Poston of Change Status of Front Tension of Front Status of ear Tension of Rear Lewer Pressure Aoier Pressure Aoier Pressure Aoier Pressure Aoier Oo Bottom
34. e a job is printing Semi Auto Gap Similar to Auto Gap Automatically determines paper thickness of the first page During single sheet feed each pages thickness IS NOT checked while a job is printing 1 2 3 4 5 6 7 8 9 Used when the same paper is used ALL of the time Bypasses the automatic head gap adjustment 1 is the narrowest gap setting 9 is the widest gap setting mabra IE Tentative setting at gap range 9 ETI Preliminary printing b gap ranga et cqrabover Pressure sensitive paper Setting of gap ig SP oF mere rang at S imterleal paper 2P or atid Appropriate gap ietting gap bevels 7 Band 9 Preliminary printing Appropriate gap tetting gap levels 1 2 4 4 and 5 Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 45 OKIDATA Service Guide ML520 521 Chapter 2 Principles of Operation Interconnect Diagram Control Board to Printhead NOTE The printhead coil resistance values ARE NOT LISTED The individual printwire control lines CANNOT be accessed on this printhead Signal Conrerster pra number peata Carriage Motor board section a cable ChE cat Th oe aST H ELS ht ove HOSL_ M HOSOA4TA h MESCLE i LE ZRA Copyright 1997 Okidata Division of OKI America
35. e below chart are in millimeters b Avie Gapand Riri Gp Adjust Cancel i 7 z Aa aA crys in ia labis j hree priri i ii Ipeni ane deel de according to the Pir ieee eign cine cE ihichrensia he arining mga Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 31 OKID AT A Service Guide ML520 521 Chapter 2 Principles of Operation Print Compensation Control The printhead compensates for the shape of the platen as shown below NOTE Also refer to Section 2 1 07 Head Drive Time 5 Aa thew in the drawing edt since the rrok hengih up to the platen is different for each pin thee information of each pin within ihe geint Fiad i fad back 1 the loger circuli trem the senor amalag cledail te pet the optimam drive kime for each pen by consrelling the pin coll ouent for each pin Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 32 OKID AT A Service Guide ML520 521 Chapter 2 Principles of Operation 2 1 05 Space and Line Feed SP LF Motor Control The LSI Location 04B MSM79V035 generates the space motor and the line feed motor control signals according to commands received from the MPU These signals are sent to the SP LF mot
36. el RSPL Both B 2 03 5 Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 79 ra Vd FA Service Guide ML520 521 OKIDATA Chapter 3 Maintenance amp Disassembly 3 2 10 PC Connector 1 Perform these procedures 3 2 01 4 3 2 0245 and 3 2 0443 2 Remove the two screws 1 and the connector holders The holders are not shown 3 Remove the PC connector 2 NOTE Installation Do not touch the contacts of the PC connector Do not touch the contacts of the space motor 3 Cleaning When cleaning refer to Section 3 4 of this Service Handbook P N 56729601 Connector PC HD40 RSPL Both B 2 07 4 Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 80 OKID AT A Service Guide ML520 521 ile Chapter 3 Maintenance amp Disassembly 3 2 11 Space Motor and Roller Guide Assemblies 1 O oO Aa W N 7 Perform these procedures 3 2 0143 3 2 0254 3 2 0455 and 3 2 1043 Remove the three screws 1 Lift the space motor assembly 2 Remove the left 3 and right connector holders 4 Remove the roller guide assembly 5 and guide roller spring 6 Use firm pressure to pull the carriage cable 7 out to detach
37. erica Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 52 F ae Service Guide ML520 521 OKIDATA Chapter 2 Principles of Operation 2 2 03 Head Gap Mechanism The head gap is automatically set for the thickness of the medium loaded in the printer In the case of envelopes where the medium thickness varies as the printhead moves along the platen the strike force of the pins changes to compensate for the differences in thickness Head Gap Setting Operation Once printing starts the space motor rotates the ribbon gear causing idle gear C to turn the change gear When the MPU requests a change in the head gap setting the GAP P signal causes the armature which is holding the change gear to be attracted to the pranger magnet The gap reset spring can now push the change gear so it contacts the gap change gear The rotation of the gap change gear causes idle gear D to turn the adjust gear The adjust gear turns the adjusting screw resulting in a new head gap setting NOTE As the adjusting screw turns counter clockwise the gap narrows As the adjusting screw turns clockwise the gap widens Narrows NEN Printhead Adjusting gear vn Platen There is a cam at each setting of the gap change gear When the change gear is at the top of the cam the change gear disengages from the gap change gear At this time the armature resets
38. f Narrow RSPL 520 B 2 04 P N 50923101 Spring Leaf Wide RSPL 521 B 2 04 4 Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business
39. ge 9 AT A Service Guide ML520 521 OKIDATA Chapter 1 Product Specifications 1 7 PAPER SPECIFICATIONS CAUTION Use Bottom Feed and or optional Pull Tractor for card stock and labels 1 7 01 Types Card Stock Weight 120 Ibs 450 g m 2 Maximum Width Microline 520 5 to 8 inches 12 7 to 20 3 centimeters Microline 521 5 to 14 inches 12 7 to 35 6 centimeters Length 3 to 17 inches 7 62 to 43 18 centimeters Thickness 017 inches 0 44 millimeters Paper Feed Path Bottom Printhead Gap Information Refer to the Printhead Gap Information Section 1 644 Continuous Form Weight Single Part 12 24 lb 45 to 90 g m 2 Multi Part Carbonless 9 11 Ib 85 to 40 g m 2 Multi Part Interleaf Paper 10 12 Ib 88 to 45 g m 2 Carbon 9 Ib 35 g m 2 Width Microline 520 3 5 to 10 5 inches 8 8 to 26 6 centimeters Microline 521 3 5 to 16 5 inches 8 8 to 41 9 centimeters Length 3 to 17 inches 7 62 to 43 18 centimeters Thickness 0 014 inches 0 36 millimeters Rear Feed 0 017 inches 0 44 millimeters Bottom Feed Paper Feed Path Rear or Bottom Printhead Gap Information Refer to the Printhead Gap Information Section 1 6 4 Cut Sheet Weight 12 to 24 Ibs 45 to 90 g m 2 Width 7 2 to 14 3 inches 18 3 to 36 3 centimeters Width Microline 520 7 2 to 8 5 inches 18 2 to 21 5 centimeters Microline 521 7 2 to 14 3 inches 18 2 to 36 3 centimeters Length 3 to 17 inches 7 62 to 43 18 centimeters T
40. generated by the coil opposes the magnetic field between the armature and the permanent magnet The armature is then driven in the direction of the platen by the force of the armature spring The print wire which is attached to the armature protrudes from the tip of the wire guide and strikes the paper through the ribbon This prints a dot on the paper As the armature gets closer to the electrode of the analog sensor the capacitance between them increases and a small amount of current flows This current is amplified and sent to the logic control LSI to indicate armature activity In order to attain optimum drive time this information is transferred to the MPU The MPU continually modifies the head gap to maintain the optimum drive time condition The analog sensor element monitors all of the pins The difference in pin stroke due to the curvature of the platen is compensated for at the logic control section of the printhead and is not transferred to the MPU After the character has been printed the permanent magnet attracts the armature and the print wires are retracted into the wire guide printhead 1 When printing Paper Armature assembly Sensor Control P C Thermistor Printhead driver Driver P C B Magnet assembly Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 49
41. ght 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 29 Ww Service Guide ML520 521 OKIDATA Chapter 2 Principles of Operation LSI Printhead Interface The connection between the LSI and the printhead is made with the bi directional serial data bus The LSI transmits the print data as serial data to the logic circuit of the printhead The printhead returns serial data from the printhead sensor analog circuit to the LSI This information is used to determine the optimum drive time for the next print request The logic circuit of the printhead signals the LSI if a parity error is detected in the print data ae TULL aren nin HOSDATA D DEF KBE HOSLT ee seis on EAR Normal es te es Ge ee parity error Oe Te a Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 30 OKID AT A Service Guide ML520 521 Chapter 2 Principles of Operation Gap Adjust Control The Gap Adjust LSI receives stroke length information for all of the printhead pins from the sensor analog circuit The Gap Adjust LSI then sets the optimum printhead gap for the printing medium NOTE Refer to Section 2 2 03 for a description of the mechanical process All values in th
42. gs are listed below Auto Gap Semi Auto Gap 1 2 3 4 5 6 7 8 9 An explanation of each setting follows Auto Gap This is the factory default Automatically determines paper thickness of the first page During single sheet feed each page s thickness is checked while a job is printing Semi Auto Gap Similar to Auto Gap Automatically determines paper thickness of the first page During single sheet feed each page s thickness IS NOT checked while a job is printing 1 2 3 4 5 6 7 8 9 Used when the same paper is used ALL of the time Bypasses the automatic head gap adjustment 1 is the narrowest head setting 9 is the widest head setting DELIUT Tentative setting at fansite ae gap range 9 Em Preliminary printing gap range w Bt grabove Setting of gap rang at S Preliminary printing Pressure sensitive paper it SP or mere Interleal paper af or mare Aphra Appropriate gap setting gap levels 6 7 Band 9 Appropriate gap petting igap levels 1 2 1 4 and 5 1 6 19 Print Modes Near Letter Quality Utility High Speed Draft 1 6 20 Print Speed Table of Print Speed and Character Matrix Mode NearLetter Quality Utility High Speed Draft Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Pa
43. gth NOTE The recommended length is specific to paper type Rear Feed Minimum 3 inches 7 62 centimeters Maximum 17 inches 43 18 centimeters Bottom Feed Minimum 3 inches 7 62 centimeters Maximum 17 inches 43 18 centimeters Top Feed Minimum 3 inches 7 62 centimeters Maximum 17 inches 43 18 centimeters 1 7 03 Number of Copies Original 4 Interleaf Original 4 Carbonless Original Cut Sheet 1 7 04 Thickness 0 014 inches 0 36 mm Maximum Thickness Rear Feed 0 017 inches 0 44 mm Maximum Thickness Bottom Feed 1 7 05 Weight NOTE The recommended weight is specific to paper type Minimum 9 lb 35 g m 2 Maximum 120 Ib 90 g m 2 1 7 06 Width NOTE The recommended width is specific to paper type Paper Microline 520 Minimum 3 5 inches 8 8 centimeters Maximum 10 5 inches 26 6 centimeters Microline 521 Minimum 3 5 inches 8 8 centimeters Maximum 16 5 inches 41 9 centimeters Printing Area Microline 520 8 inches Maximum Microline 521 13 6 inches Maximum Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 10 OKID AT A Service Guide ML520 521 i l Chapter 1 Product Specifications 1 8 MEMORY SPECIFICATIONS 1 8 01 EEPROM 1 Kbit serial EEPROM used to store Menu data 1 8 02 EPROM 1 MBit EPROM Printer Control Program Fonts
44. he release cam Slide the cam and spring away from the base frame until the opposite end of the spring can be installed into the frame Make sure that the front release gear arm is engaged as shown A Lubrication When lubricating refer to Section 3 5 of this Service Handbook Front Release Gear Shaft P N 50805201 Lever Switch RSPL Both B 2 06 5 P N 50805301 Cam Release RSPL Both B 2 05 55 P N 50923301 Spring Pressure Narrow RSPL 520 B 2 06 P N 50923401 Spring Pressure Wide RSPL 521 B 2 06 4 P N 51228301 Arm Front Release Gear RSPL Both B 2 06 4 Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 94 OKID AT A Service Guide ML520 521 FP ores CE Y Chapter 3 Maintenance amp Disassembly 3 2 25 Carriage Shaft CAUTION The space motor assembly etc may be left in place when removing the carriage shaft However use extra care when doing so The carriage cable should be detached from the space motor before removing the carriage shaft 1 Perform these procedures 3 2 0145 3 2 06 4 3 2 07 4A and 3 2 1653 Push the end A of the carriage shaft 1 until it clears the base frame Pull the carriage shaft free of the base frame Remove the support protect reset spring 2 Remove the support protector assembly 3 Oo oo fF W N Remove the fr
45. hickness 0 014 inches 0 325 millimeters Maximum Paper Feed Path Top Printhead Gap Information Refer to the Printhead Gap Information Section 1 6 4 Envelopes Weight 24 Ibs 90 g m 2 Maximum Size Single Feed Minimum 6 5 x 3 6 inches 16 5 x 9 1 centimeters Maximum 9 5 x 4 1 inches 24 1 x 10 4 centimeters Continuous Non overlap type Thickness 014 inches 325 millimeters Maximum Paper Feed Path Bottom Printhead Gap Information Refer to the Printhead Gap Information Section 1 6 5 Labels Weight N A Width Microline 520 3 5 to 10 5 inches 8 8 to 26 6 centimeters Microline 521 3 5 to 16 5 inches 8 8 to 41 9 centimeters Length 3 to 17 inches 7 62 to 43 18 centimeters Thickness 011 inches 0 28 mm Maximum including backing Paper Feed Path Bottom Printhead Gap Information Refer to the Printhead Gap Information Section 1 6 4 CAUTION Use Bottom Feed and or optional Pull Tractor for card stock and labels Transparency NOTE Roller marks may mar the transparency under high temperature high humidity conditions Weight 12 to 24 Ibs 45 to 90 g m 2 Width Microline 520 7 2 to 8 5 inches 18 2 to 21 5 centimeters Microline 521 7 2 to 14 3 inches 18 2 to 36 3 centimeters Length 3 to 17 inches 7 62 to 43 18 centimeters Thickness 0 14 inches 0 36 millimeters Paper Feed Path Top Printhead Gap Information Refer to the Printhead Gap Information Section 1 6 4 1 7 02 Len
46. hould contact the sensor only when the change lever is in the top feed middle setting If the lever is not correctly positioned the ALARM lamp will light and the unit will not automatically load paper or receive data When cleaning refer to Section 3 4 of this Service Handbook P N 51009401 Guide Sheet Narrow RSPL 520 B 2 02 P N 51009501 Guide Sheet Wide RSPL 521 B 2 02 P N 53066902 Cover Upper Narrow RSPL 520 B 2 02 P N 53067002 Cover Upper Wide RSPL 521 B 2 02 5 P N 53067101 Cover Access Narrow RSPL 520 B 2 02 5 P N 53067201 Cover Access Wide RSPL 521 B 2 02 5 P N 53067301 Cover B for card slot RSPL Both B 2 03 5 P N 53562601 Knob Platen ML500 Series RSPL Both B 2 03 Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 76 FA Service Guide ML520 521 OKIDATA Chapter 3 Maintenance amp Disassembly 3 2 07 Control Board FJIM 1 Perform these procedures 3 2 01 4 and 3 2 06 53 2 Remove the two screws 1 3 Release the control board 2 from the bracket 3 4 Tilt the board to access the connectors 5 Detach connectors CN6 operator panel 4 CN7 carriage cable 5 CN3 power supply 6 and CN5 line feed motor 7 6 Remove the board NOTE Installation The bottom sensor lever must be positioned in
47. ing occur Print Quality is darker on one side of the document Parts are replaced Printhead 3 2 02 Space Motor Assembly 3 2 11 3 Space Rack 3 2 13 Guide Rail 3 2 15 3 Platen Assembly 3 2 19 Carriage Shaft 3 2 25 Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 69 OKIDATA Service Guide ML520 521 2 j Chapter 3 Maintenance amp Disassembly 3 2 DISASSEMBLY ASSEMBLY PROCEDURES General Information This section contains the printer disassembly procedures Only the removal procedures are explained here Reverse the procedure for the installation At the bottom of each procedure is a listing of the parts covered in that procedure The Okidata part number item description comment RSPL Option Consumable and cross reference to Appendix B is provided for each part Items included in the Recommended Spare Parts List are indicated by the acronym RSPL N A will appear where a part number is not available 520 indicates that the item is specific to the Microline 520 521 indicates that the item is specific to the Microline 521 Both indicates that the item is common to both printers C Fat herm Coredrent Appendix E Hurnber Description Reference This Service Handbook lists the disassembly procedures for major components of the unit Okidata DOES NOT recommend disassembling
48. ion FORM FEED Load Print Quality Selection Top of Form Tear Quiet Reset 1 6 08 Graphics Resolution Graphics Resolution 288 horizontal x 144 vertical dots per inch DPI maximum 1 6 09 Interface Standard Centronics Parallel Optional RS232C Serial 1 6 10 Line Feed Increments Fixed 6 lines per inch lpi 0 167 inch 4 23 millimeters 8 lines per inch lpi 0 125 inch 3 175 millimeters Variable n 60 inch n 72 inch n 144 inch n 216 inch 1 6 11 Line Feed Time 65 milliseconds 6 lines per inch lpi 6 milliseconds 8 lines per inch lpi 1 second 5 0 inches Continuous paper feed rate 1 6 12 Menu Mode Po Switch tion Paper park Prints the entire menu Line Feed Reverse Selects Group Function Selectsttem Y FORM FEED Load Selects Item Value SEL Menu Exits Menu Mode Enters Select 1 6 13 Paper Feed Methods Standard Friction Feed Top Rear Push Tractor Rear Optional Pull Tractor Bottom Bottom Push Tractor Feed Bottom Single Bin Cut Sheet Feeder Top CSF 5000 Narrow CSF 5001 Wide 1 6 14 Paper Feed Paths Top Feed Standard Rear Feed Standard Bottom Feed by using an Optional feed mechanism Special Features Paper Park Automatic Paper Loading Forms Tear Off 1 6 15 Paper Loading Auto Loading Top Feed Press FORM FEED Load switch to feed paper to default position 1 6 16 Paper Out Detection Distance from end of paper Rear Feed 0 5 inches
49. ivision of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 75 AT A Service Guide ML520 521 OKIDATA Chapter 3 Maintenance amp Disassembly 3 2 06 Upper Cover Access Cover and Sheet Guide Assemblies 1 Perform this procedure 3 2 01 5 2 Pull the platen knob 1 straight out and remove it 3 Set the change lever 2 to the bottom feed position toward the rear of the printer 4 Insert a flat blade screwdriver into the grooves 3 of the frame and pry the upper cover 4 away from the frame 5 Raise the front side of the upper cover assembly 6 Tilt the upper cover assembly toward the rear to disengage the claws not shown at the rear of the frame 7 Lift the upper cover assembly and remove it CAUTION Do not rotate the access cover past the vertical when removing it or you will break the tab extensions 8 Raise the access cover assembly 5 until it is vertical then lift it straight up to remove it 9 Remove the sheet guide assembly 6 10 Note the position of the cover B for card slot 7 This is part of the upper cover and should not be removed No font cards are currently available CAUTION When installing the upper cover make sure that the sensors correctly contact the control board 3 2 07 a The cut sheet continuous sensor lever must be positioned below the BASW sensor The lever s
50. k of Microsoft Corporation PC is a registered trademark of International Business Machine Corporation Proprinter is a registered trademark of International Business Machine Corporation Windows Is a trademark of Microsoft Corporation Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 3 OKID AT A Service Guide ML520 521 lt fers Chapter 1 Product Specifications 1 1 01 General Information The Microline 520 and Microline 521 are letter quality nine pin dot matrix printers which utilize OKISMART paper handling Patented Okidata technology does away with the manual head gap adjustment The printer actually reads and learns the print medium being used then automatically adjusts the head gap to the optimum distance This autogapping process leads to longer printhead life Options include the Bottom Feed Push Tractor Cut Sheet Feeder Pull Tractor and Serial Interface Board The Microline 520 is an 80 column printer The Microline 521 is a 132 column printer Okidata s one year limited warranty covers the parts labor and printhead on both printers The following items are available for the printer OKISMART Typer software which provides the flexibility for the Microline 590 521 to function like a typewriter on checks labels and envelopes OKISMART Panel a utility program that lets yo
51. n frame Just before paper is loaded the printhead moves towards the left bracket and unlatches the support protector As the printhead moves to the right the support protector reset spring pushes the support protector toward the center of the platen With the support protector in this position the ribbon protector and the support protector prevent the leading edge of the paper from curling or folding Once the paper is ejected the printhead slowly moves towards the left bracket The support protector is latched in the stored position when it is pushed to approximately 5 mm from the left bracket e About Smr finan i Ribbon protector Printhead Carriage frame assembly gt Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 63 OKID AT A Service Guide ML520 521 3 Chapter 2 Principles of Operation 2 2 08 Automatic Paper Load The Microline 520 521 printers will automatically detect cut sheet paper and feed the paper to the Top of Form TOF position Cut Sheet Paper Set the change lever to the TOP FEED position NOTE When the change lever is in the TOP FEED position the cut sheet detection lever contacts the cut sheet detection switch BASW which is located on the main control board Insert the sheet of paper between the platen and the paper chute Once paper is de
52. n of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 26 Ww Service Guide ML520 521 OKIDATA Chapter 2 Principles of Operation 2 1 02 Initialization This printer is initialized when the printer is powered on or when the I PRIME N signal is input from the host via the parallel interface The steps in Printer Initialization are listed below The RST N signal is output from the reset circuit to reset the MPU and LSls The program is executed and the LSIs are reset by the MPU via IORST N NOTE A reset operation initiated by I PRIME does not reset the MPU The program sets the LSI 02D mode checks the memory ROM RAM then executes carriage homing and determines the phase of the line feed motor Finally the program establishes the interface signals P I F ACK P signal sending and S I F BUSY N signal off and lights the SELECT lamp to indicate that the printer is in the ON LINE state MPU LSI Resetting and Initial setting VF BUSY ON RAM Check Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 27 Ww Service Guide ML520 521 OKIDATA Chapter 2 Principles of Operation 2 1 03 Parallel Interface Control The parallel data input from the host to the interface LSI is la
53. nce amp Disassembly 3 2 15 Guide Rail and Adjust Cam 1 Perform these procedures 3 2 01 4A 3 2 0245 3 2 04 5 3 2 1043 3 2 1145 and 3 2 1443 2 Rotate the adjust cam 1 in the direction of arrow A as far as possible 3 Pull the cam out and remove it 4 Carefully press the claw 2 location only in the base frame down to release the guide rail 3 Do not press too hard or the claw will break 5 Use a straight slot screwdriver to slide the guide rail in direction of arrow A 6 Lift the guide at position B and work the other end of the guide free to remove the guide rail 7 Remove the ground clip 4 NOTE Installation After installing the guide rail check the printhead gap adjustment Refer to Section 3 3 of this Service Handbook i P N 51009701 Guide Rail Ground Clip RSPL Both B 2 04 P N 51009801 Guide Rail Narrow RSPL 520 B 2 04 45 P N 51009901 Guide Rail Wide RSPL 521 B 2 0443 P N 53067701 Cam Adjust RSPL Both B 2 04 3 Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 85 OKID AT A Service Guide ML520 521 i J l Chapter 3 Maintenance amp Disassembly 3 2 16 Left Ground Plate 1 Perform these procedures 3 2 0145 3 2 06 i j and 3 2 0743 2 Cut the nylon tie and release the cable Not shown 3 Work the left ground plate
54. nsumption Operating 110 VA Idle 40 VA Local Test 70 VA 1 3 03 Power Frequency 120 VAC 60 Hz 2 230 240 VAC 50 60 Hz 2 Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 6 r C Service Guide ML520 521 OKIDATA Chapter 1 Product Specifications 1 4 ENVIRONMENTAL CONDITIONS 1 4 01 Acoustic Rating Near Letter Quality Mode Microline 520 54 9 dBA Microline 521 54 4 dBA Utility Mode Microline 520 57 2 dBA Microline 521 56 9 dBA Quiet Mode Microline 520 52 5 dBA Microline 521 52 3 dBA 1 4 01 Altitude 10 000 feet 8 050 meters 1 4 03 Ambient Temperature and Relative Humidity RH While operating 41 to 104 degrees Fahrenheit 5 to 40 degrees Celsius Operating humidity 20 to 80 RH While in storage 14 to 122 degrees Fahrenheit 10 to 50 degrees Celsius Storage humidity 5 to 95 RH Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 7 7 DATA Service Guide ML520 521 OKI Chapter 1 Product Specifications 1 5 AGENCY APPROVALS 1 5 01 Listings UL No UL Standard No 1950 D3 CSA No CSA Standard 22 2 950 D3 FCC FCC Certified per Part 15 Subject J Class B IEC IEC 950 VDE VDE 0805 VDE 0875 Class B
55. ntenance amp Disassembly 3 2 20 Paper Chute Assembly 1 Perform these procedures 3 2 01 3 2 0645 and 3 2 1943 2 Remove the rear pressure roller 1 3 Use a straight slot screwdriver to release the claws of the lock spring 2 and remove the spring 4 Remove the paper chute assembly 8 NOTE The paper chute assembly includes the levers for the rear and top paper feed paths P N 53341301 Roller Pressure Rear Narrow RSPL 520 B 2 06 4 P N 53341401 Roller Pressure Rear Wide RSPL 521 B 2 06 5 P N 50924701 Spring Lock RSPL Both B 2 06 P N 50097701 Paper Chute Assembly N RSPL 520 B 2 06 5 P N 50097801 Paper Chute Assembly W RSPL 521 B 2 06 5 Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 90 OKIDATA Service Guide ML520 521 Chapter 3 Maintenance amp Disassembly 3 2 21 Line Feed Motor Assembly 1 Perform these procedures 3 2 0145 3 2 0645 3 2 07 4 3 2 16 i 3 2 19 3 3 2 20 and 3 2 21 this section 2 Firmly press down on the line feed motor assembly 1 while tilting the assembly out 3 Remove the line feed motor assembly 4 Remove the line feed connection cord 2 CAUTION The line feed idle gear 3 should be removed only if it must be replaced The claws will break when the gear is removed A new gear must be installed
56. nu Settings 104 3 3 05 Top of Form 105 0 3 06 Paper Park 106 3 3 07 Tear Feature 107 3 3 08 Forms Tear Off 108 3 3 09 Resets 109 3 4 Cleaning 110 3 5 Lubrication 111 3 6 Shipping Instructions 112 4 Failure amp Repair Analysis 4 1 01 Introduction 113 4 1 02 Printer Serial Number Identification 114 4 1 03 Firmware Revision Identification 115 4 2 Reporting Problems General Information 116 4 2 02 Problem Lists 117 4 2 03 Reporting Methods 118 4 3 Troubleshooting Updates 119 4 4 Troubleshooting Tips 120 4 4 02 Problem Categories 121 4 4 03 START HERE Flowchart 122 Table of Contents Page 4 4 04 Tips for Preventing Image Problems 123 4 4 05 Common Problems 124 4 5 Abnormal Output Output Samples 125 Left Margin Drifting Problem 126 4 6 Fault Alarms 127 4 6 02 ALARM LED Display Troubleshooting Table Index 128 4 6 03 ALARM LED Display Troubleshooting Tables 129 4 7 Repair Analysis Procedures Raps 130 4 7 02 RAP Index 131 rey RAP 01 No Power Supplied to Printer 132 itera RAP 02 No Spacing Operation 133 eee RAP 03 Printhead Homing Error 134 Seek RAP 04 Paper Jam During Paper Loading 135 EPEE RAP 05 Printhead Pins Not Firing 136 ee RAP 06 Poor Print Quality 137 eee RAP 07 Ribbon Feed Problem 138 ere RAP 08 Line Feed Problem 139 ae RAP 09 Operation Panel Malfunction 140 er RAP 10 Parallel Interface Problem 141 n RAP 11 Serial Interface Problem 142 4 8 Printer Te
57. o maintain the desired speed for each print mode wl e le L SP uih lable H Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 35 OKIDATA Service Guide ML520 521 Chapter 2 Principles of Operation Encoder Disk As the space motor operates the encoder disk spins When the encoder disk interrupts the photo sensors the signals Phase A and Phase B are generated The LSI Location 04B MSM79V035 divides these edge pulse signals the frequency division is based on the selected print pitch to generate the signal IPT The IPT signal provides dot on timing and carriage position detection timing fie LJ LTU JT LILI TITY MNIE wt t 2 ot oT Pal a z A ir l se IT ie LO MODE ua a 17 iE law CPD OP Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 36 FA Service Guide ML520 521 OKIDATA Chapter 2 Principles of Operation 2 1 06 Operation Panel The Serial I O Port Ports 20 23 of the MPU reads the operation panel switch data from the operation panel control LSI Location IC1 BUS148S A two byte 15 bits 1 parity bit even parity command OPTXD is transmitted from the MPU to the operation
58. or driver Tranamiioon of SLF ober Contre Gale Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 33 OKIDATA Service Guide ML520 521 l Chapter 2 Principles of Operation Line Feed Motor Control The SP LF motor driver Location 5A MHM2025 drives the line feed motor in two phase bipolar based on the phase changeover data output from the LSI The serial data from the LSI 04B MSM79V035 is processed by a register contained in the SP LF motor driver to measure the overdrive time and to change the phase DF LL oe L FORWARD REVERSE Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 34 Ww Service Guide ML520 521 OKIDATA Chapter 2 Principles of Operation Space Motor Control The SP LF motor driver Location 5A MHM2025 drives the three phase brushless motor Motor movement is based on the phase signal SPU SPV and SPW and the speed instruction data from the LSI The MPU can identify the current speed of the space motor by measuring the pulse width of the output Phase A Phase B of the encoder disk sensor After comparing the target speed for each print mode with the actual speed the motor is accelerated or decelerated t
59. out This Manual This document may not be reproduced without the written permission of the Okidata Technical Training Group Every effort has been made to ensure the accuracy of the information contained in this training course Okidata is not responsible for errors beyond its control 1994 by Okidata All rights reserved First Edition February 1993 P N 59257801 Second Edition September 1993 P N 59257802 Third Edition December 1994 P N 59257803 Written and produced by the Okidata Technical Training Group Please address any comments on this publication to Technical Training Group Okidata 532 Fellowship Road Mount Laurel NJ 08054 3499 Fax Number 609 235 2600 ext 7034 Okilink Login Name Technical Training OKIDATA is a registered trademark of Oki Electric Industry Company Ltd marques deposee de Oki Electric Industry Company Ltd marca registrada Oki Electric Industry Company Ltd MICROLINE is a registered trademark of Oki Electric Industry Company Ltd marque depose de Oki Electric Industry Company Ltd OkiSmart Paper Handling is a trademark of Oki Electric Industry Company Inc PLUG n PRINT is a registered trademark of Oki America Inc marque deposee de Oki America Inc Bitstream is a registered trademark of Bitstream Incorporated Epson is a registered trademark of Seiko Epson Corporation IBM is a registered trademark of International Business Machine Corporation MS DOS is a registered trademar
60. panel LSI in synchronization with the OPCLK signal Once the LSI decodes the command the command must pass a command code check and have no parity errors Then the specified I O control will return the two byte command response to the MPU Hate From the illustraten above you can see thal the command and the comand meporie are Gerlperl ag iha iame tite This ia because the bit Oto bit Pal OPRANO are fined so that the respone can Ge returned betore decading tet commanc Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 37 Ww Service Guide ML520 521 OKIDATA Chapter 2 Principles of Operation 2 1 07 Alarm Circuit Driver Circuit Alarm Processing The printhead driver output and the head gap magnet output drive signals are monitored at R29 and C8 The POWER OFF P signal is output by the comparator Location 02C IC2901 when driven for more than the specified time This signal becomes the ALM signal The ALM signal is sent to the power supply board and causes the DC voltages to be turned off HDALM AN GAP MOW POWER OFF P COR MDV Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 38 OKIDATA Service Guide ML520 521 l Chapter 2 Principle
61. pyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 65 OKIDATA Service Guide ML520 521 wis Chapter 2 Principles of Operation 2 2 09 Paper Park If continuous feed paper is installed and printing on cut sheet paper is desired it is not necessary to unload the continuous feed paper The Paper Park feature provides a means of retracting the continuous feed paper from the paper path while at the same time cut sheet paper is fed Paper Park Operation Place the change lever in the REAR FEED or BOTTOM FEED position Press the PARK switch on the operation panel A reverse line feed operation retracts the paper until paper end occurs or 19 inches of paper have been retracted NOTE Retracting 19 inches of paper without detecting a paper end condition causes the line feed operation to stop The line feed operation stops because the printer assumes a jam has occurred The operator can press the SEL switch to reset the ALARM LED and press the PARK switch to continue the park operation This operation may be useful when length of the paper to be parked is greater than 19 inches Paper end detection V LF actions PEPE OEE LED AANA RAAR Reverse LF from P E Sensor to tri Reverse LF until paper end or 19 inches max Copyright 1997 Okidata Division of OKI America Inc All rights reserved
62. s of Operation Low Motor Drive Voltage Alarm 40V is converted into the POWLEV signal 0 vdc to 5 vdc by the voltage divider network of R542 and R544 then input to the A D port of the MPU The value of this voltage is used to control the drive time and the print speed pass number of the head 40V POWLEV Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 39 OKIDATA Service Guide ML520 521 l Chapter 2 Principles of Operation Head Drive Time The head drive time is modified to compensate for the amount of the voltage drop of the POWLEV signal By monitoring the voltage drop every 500 microseconds the MPU is able to control and maintain the impact necessary for each printhead pin Print AN 16 C 1 100 a 1 PASS Bi directional print 110 C Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 40 DATA Service Guide ML520 521 OKI Chapter 2 Principles of Operation Print Speed 34vdcor greater 1 100 382vdeto 34vde 1 Approximately 85 30vdcto 32vde 1 Approximately 50 30 vdc or less a se Less than 50 Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKI
63. s the Rear Sensor Lever rotate The Rear Sensor Lever rotates unblocking the Rear Top Paper End Sensor SNS1 Rear Feed Detection When paper is fed from the Rear Push Tractor Point B is pushed backward This makes the Sensor Lever rotate As the Sensor Lever rotates it contacts the Rear Sensor Lever This makes the Rear Sensor Lever rotate The Rear Sensor Lever rotates unblocking the Rear Top Paper End Sensor SNS1 Bottom Feed Detection When the paper is fed from the bottom of the printer Point C is pushed rotating the Bottom Paper End Lever As the Bottom Paper End Lever rotates it contacts the Bottom Sensor Lever This makes the Bottom Sensor Lever rotate The Bottom Sensor Lever rotates unblocking the Bottom Paper End Sensor SNS2 NOTE The method for detecting a paper end condition is the reverse of the above PAPER END is detected when the Bottom Paper End Sensor SNS2 is blocked Paper near end lever B Rear and Top paper end sensor f Paper mear end lever A Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 62 C Service Guide ML520 521 OKIDATA Chapter 2 Principles of Operation 2 2 07 Support Protector Mechanism During printer initialization the support protector is latched in the stored position approximately 5 mm from the left bracket of the mai
64. sts 143 4 8 02 Rolling ASCII Test 144 4 8 03 Font Test 145 4 8 04 Serial Interface Loopback Test 146 ee serial Cable Information 147 eer Serial Interface Signal Requirements 148 ai Commonly Used Serial Cable Configurations 149 4 8 05 Hexadecimal Dump Mode 150 4 9 Resistance Checks 151 ee Layout Diagram 152 4 9 02 Printhead 153 4 9 03 Line Feed Motor Resistance 154 4 9 04 Space Motor Resistance 155 A Reference Charts A 1 Overview A 1 01 General Information 156 A 2 Index To Charts 157 ee Board Layout 158 A 2 01 Main Controller Board FJIM 159 A 2 02 Operator Panel Board LEOP 160 A 2 03 Power Supply Assembly 161 A 2 04 Space Motor Board 162 A 2 05 RS232 C Serial Interface Board Option LXHI 163 B Illustrated Parts Listing B 1 Overview B 1 01 General Information 164 Table of Contents Page ey Format 165 oe Current Part Numbers 166 B 1 02 Definition of Terms 167 B 1 03 Parts Ordering Information 168 B 2 Charts 169 a Overview 170 B 2 01 Printer 171 B 2 02 Upper Cover Assembly 172 B 2 03 Printer General Assembly 173 B 2 04 Printer Unit 174 B 2 05 Printer Unit 175 B 2 06 Printer Unit 176 B 2 07 Carriage Assembly 177 B 2 08 Options 178 B 2 09 Option Parts 179 B 2 10 Consumables 180 B 2 11 Packing Materials 181 B 2 12 Documentation 182 B 2 13 Service Training Kit Revision List 183 Page 2 OKIDATA Se haper Ab
65. tched to the internal register at the falling edge of the STROBE N signal The LSI sets the BUSY N signal to inform the host that the data is being processed The LSI also outputs the RXD N signal to inform the MPU of data reception The data is read upon receiving the RD N signal from the MPU When the data processing is complete the BUSY N signal is disabled and the ACK N signal is sent to request the next data When the buffer is full and reception is not desired the BUSY signal is sent to request data transmission be stopped MPU Falling ee Rising _ JL Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 28 Ww Service Guide ML520 521 OKIDATA Chapter 2 Principles of Operation 2 1 04 Print Control The print data is transmitted as serial data from the LSI to the control circuit and the driver contained in the printhead After the data is printed the sensor analog circuit controlling each pin returns the pin stroke data to the MPU The MPU will make an automatic head gap adjustment This feedback system sets the optimum drive time for each pin in order to maintain high print quality In the case of envelopes where the medium thickness varies as the printhead moves along the platen the strike force of the pins changes to compensate for the differences in thickness Copyri
66. tected at the paper end sensor and the amount of time selected on the Wait Time setting of the menu has lapsed the line feed motor will feed the paper until the leading edge of the paper reaches the top of form position Sheet setting a Time out PE Vv Detection timer time selected on the menu LF action A een fear side ana Batre Change hever i Cut sheet Cut sh d detection lever rl detection switch Cut sheet oF secon lever Cut sheet Getection switch Cut sheet detection lever Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 64 C Service Guide ML520 521 OKIDATA Chapter 2 Principles of Operation Continuous Feed Paper Set the change lever to either the REAR FEED or BOTTOM FEED position NOTE When the change lever is in the REAR FEED or BOTTOM FEED position the cut sheet detection lever does NOT contact the cut sheet detection switch BASW which is located on the main control board Place continuous feed paper in the appropriate tractor Press the FF LOAD switch The line feed motor will feed the paper until the leading edge of the paper reaches the top of form position Push down the FF LOAD switch yy Detection of the sheet supplied LF actian Line feed about 3 inches until the detection of the sheet supplied Co
67. ter 2 Principles of Operation Continuous Paper Feed Bottom Tractor Feed Mechanism As the platen rotates power is transferred to the drive gear from the platen gear the idle gear and the tractor change gear The drive gear turns the pin tractor belts on the bottom tractor feed unit which feeds the continuous paper In kria hel Drive gear Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 60 OKIDATA Service Guide ML520 521 Chapter 2 Principles of Operation Continuous Paper Feed Push Pull Tractor Mechanism This mechanism consists of an optional pull tractor and a standard push tractor mechanism Continuous paper is fed by these two tractors at the same time C Pull maces cy Drive gear Idle gear Platen gear Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 61 TA Service Guide ML520 521 OKIDATA Chapter 2 Principles of Operation 2 2 06 Paper Detection Mechanism Top Feed Paper Detection When cut sheet paper is inserted into the printer Point A of the Rear Top Paper Feed Lever is pushed backward causing the Sensor Lever to rotate As the Sensor Lever rotates it contacts the Rear Sensor Lever This make
68. the cable from the space motor assembly Remove the space motor assembly NOTE The guide roller assembly includes the guide roller 8 the guide roller holder 9 and the pin 10 Installation Position the guide roller assembly first The contact side of the cable faces down when the carriage cable is inserted into the connector on the space motor assembly Work the cable from side to side until it is fully seated in the connector No contacts should be visible After installing the space motor assembly check the printhead gap adjustment Refer to Section 3 3 of this Service Handbook i When lubricating refer to Section 3 5 of this Service Handbook P N 53343001 Holder Connector L RSPL Both B 2 07 5 P N 53343101 Holder Connector R RSPL Both B 2 07 5 P N 56510401 Motor Space Assembly RSPL Both B 2 07 4 P N 53343301 Guide Roller Assembly Both B 2 07 P N 53341901 Roller Guide RSPL Both B 2 07 3 P N 53342001 Holder Guide Roller RSPL Both B 2 07 P N N A Pin Both B 2 07 4 P N N A Guide Roller Spring Both B 2 07 Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 81 OKID AT iN service Guide ML520 521 re Chapter 3 Maintenance amp Disassembly 3 2 12 Carriage Cable 1 Perform these procedures 3 2 01 3 2 06 4 3 2 07 1 and 3 2 11
69. the transformer assembly 8 Remove the screw 9 from the ground wire of the filter board 9 Use a straight slot screwdriver to detach the claw 10 tilt the filter board upward then work the AC inlet and the AC switch free 10 Lift and remove the filter board assembly NOTE When installing verify that the AC inlet and AC switch are oriented correctly P N 56412401 Transformer 120 V ML520 RSPL 520 B 2 03 P N 56412402 Transformer 120 V ML521 RSPL 521 B 2 03 5 P N 55073201 PCB Filter 120 V RSPL Both B 2 03 4 P N 50707501 Clamp Cord RSPL Both B 2 03 4 P N 56306201 Fuse 1A 250V Filter Brd 220V Option RSPL Both B 2 03 P N 56306101 Fuse 2 5A 125V Filter Board RSPL Both B 2 03 4 Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 78 OKIDATA Service Guide ML520 521 Chapter 3 Maintenance amp Disassembly 3 2 09 Operator Panel PCB LEOP 1 Perform these procedures 3 2 01 3 2 06 4 and 3 2 0743 2 Cut the nylon tie and release the cable Not shown 3 Disengage the claws 1 on both sides of the frame 4 Lift the operator panel assembly 2 straight up and remove it 5 Open eight claws 3 and remove the operator panel board 4 from the operator panel 5 P N 53562703 Panel Operator RSPL Both B 2 03 4 P N 55937502 PCB LEOP Operator Pan
70. u control selected printer functions from your personal computer Scalable Fonts 14 scalable fonts available on diskette NOTE The OkiSmart software includes three programs 1 OkiSmart Control 2 OkiSmart Panel Emulator 3 OkiSmart Setup Refer to the Printer Handbook for more information Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 4 C Service Guide ML520 521 OKIDATA Chapter 1 Product Specifications 1 2 PHYSICAL SPECIFICATIONS 1 2 01 Dimensions NOTE Dimensions INCLUDE the platen knob acoustic cover and paper separator Microline 520 Width 16 9 inches 43 centimeters Depth 14 9 inches 37 8 centimeters Height 6 5 inches 16 5 centimeters Microline 521 Width 23 inches 58 4 centimeters Depth 14 9 inches 37 8 centimeters Height 6 5 inches 16 5 centimeters 1 2 02 Printer Weight Microline 520 17 6 pounds 8 0 kilograms Microline 521 23 1 pounds 10 5 kilograms Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 5 OKIDATA Service Guide ML520 521 l Chapter 1 Product Specifications 1 3 POWER REQUIREMENTS 1 3 01 Input Power 120 VAC 5 5 15 230 240 VAC 10 14 1 3 02 Power Co
71. ush Tractor Kit P N 70022901 is a narrow feeder for the Microline 520 The Bottom Push Tractor Kit P N 70023101 is a wide feeder for the Microline 521 Bottom Feed Paper Type Continuous Feed Includes Stand and Metal Tear Bar Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 15 OKIDATA Service Guide ML520 521 Chapter 1 Product Specifications 1 10 05 Serial Interface Super Speed 19 2K RS 232C Ready Busy X On X Off Protocols Can be configured through the Menu or OKISmart Utility Program Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 16 OKIDATA Service Guide ML520 521 Chapter 1 Product Specifications 1 10 06 Roll Paper Stand Adapts printer for use with roll type paper Model 520 only Includes Stand Support Cord and DIN plug for connection to printer Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 17 OKID AT A Service Guide ML520 521 Chapter 1 Product Specifications 1 10 08 OKISmart Typer Utility Obtained via BRC Business Reply Card packaged with printer Includes Type
72. ved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 57 OKIDATA Service Guide ML520 521 a Chapter 2 Principles of Operation Continuous Paper Feed Rear Tractor Mechanism As the platen rotates power is transferred to the tractor gear from the platen gear the idler gear and the change gear The tractor gear drives the pin tractor belts which feed the continuous paper Platen gear Tractor gear Change gear Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 58 OKIDATA Service Guide ML520 521 Chapter 2 Principles of Operation Continuous Paper Feed Pull Tractor Mechanism Bottom feed of continuous sheets is possible only when an optional pull tractor unit is installed As the platen rotates power is transferred to the drive gear from the line feed idler gear the platen gear idler gear B and idler gear A The drive gear turns the pull tractor assembly which feeds the continuous paper Continuous form Pull Pottam Tractor assembly er a Li mi LF idle gear Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 59 OKIDATA Service Guide ML520 521 Chap
73. writer Mode Form Creation Utility and Barcode Utility 1 10 09 OKISmart Panel Utility Obtained via BRC Business Reply Card packaged with printer Includes Front Panel Control Utility and Drivers for Windows 3 0 amp 3 1 NOTE The OKISmart software includes three programs 1 OKISmart Control 2 OKISmart Panel Emulator 3 OKISmart Setup Refer to the Printer Handbook for more information Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http opx okidata com Page 18 DATA Service Guide ML520 521 OKI Chapter 1 Product Specifications 1 11 RELIABILITY 1 11 01 Mean Time Before Failure MTBF Approximately 6 000 hours 25 duty cycle 35 page density 1 11 02 Mean Time To Repair MTTR Approximately 15 minutes to major sub assembly level 1 11 03 Printer Life Approximately 16 000 hours of power on time 25 duty cycle 35 page density 1 11 04 Printhead Life Average 200 million characters in 10 cpi utility mode normal 25 duty 35 page density 1 11 05 Ribbon Life Approximately 4 million characters 1 11 06 Warranty Limited One year parts and labor 1 11 07 Service Authorized OKIDATA Service Centers Copyright 1997 Okidata Division of OKI America Inc All rights reserved See the OKIDATA Business Partner Exchange BPX for any updates to this material http bpx okidata com Page 19

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