Oki ML521, ML520 manual Principles of Operation, Ram

Page 39

Page: 23

Service Guide ML520/521

Chapter 2 Principles of Operation

RAM

Location 05CB: 511664Z

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.

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)

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Contents About This Manual ML520 // ML521 Dot Matrix PrintersService Guide ML520/521 Maintenance & Disassembly Failure & Repair Analysis Illustrated Parts Listing Table of Contents Service Guide ML520/521 Page Product Specifications General Information Microline Printer Weight MicrolinePower Requirements Product SpecificationsAltitude Ambient Temperature and Relative Humidity RHProduct Specifications Agency Approvals 1.5.01 Listings HSD CPI CPSHoriz. DPI Vert. DPI IPSUPC a UPC E EAN Fonts Near Letter Quality Front Panel SwitchesGraphics Resolution EmulationsForm Feed / Load Selects Item Menu Mode Switch ActionLine Feed Increments Fixed Selects Group FunctionPrint Method Printhead Type General Information Paper LoadingPaper Out Detection Paper Tear CapabilitiesSemi Auto Gap Printhead Gap AdjustmentGap Control Auto Gap80 12 cpi 320 12 cpi 427 12 cpi Print ModesCut Sheet Paper SpecificationsTypes Card Stock Continuous FormEnvelopes LabelsTransparency Thickness WeightLength Number of CopiesWidth PaperPrinting Area 03 RAM Memory SpecificationsEeprom EpromProduct Specifications Consumables 1.9.01 Ribbon Dual Bin Page Product Specifications Pull Tractor Kit Product Specifications Bottom Push Tractor Kit Product Specifications Serial Interface Product Specifications Roll Paper Stand OKISmart Panel Utility Product Specifications OKISmart Typer UtilityReliability Electrical Operation Principles of OperationPrinciples of Operation Main Control Board Principles of Operation Block Diagram Principles of Operation Program ROM RAM LSI Service Guide ML520/521 Principles of Operation Initialization Reset operation initiated by I-PRIME does not reset the MPUPrinciples of Operation Parallel Interface Control Principles of Operation Print Control Principles of Operation LSI/Printhead Interface Principles of Operation Gap Adjust Control Also refer to .1.07 Head Drive Time Principles of Operation Print Compensation ControlService Guide ML520/521 Principles of Operation Line Feed Motor Control Principles of Operation Space Motor Control Principles of Operation Encoder Disk Principles of Operation Operation Panel Page Service Guide ML520/521 Principles of Operation Low Motor Drive Voltage Alarm Principles of Operation Head Drive Time +34 vdc or greater Less than 50%Principles of Operation Head Overheat Alarm Processing Voltage/Signal Purpose Principles of Operation Power Supply CircuitService Guide ML520/521 Principles of Operation Printhead Gap Information Page Service Guide ML520/521 Principles of Operation Line Feed Motor Resistance Principles of Operation Space Motor Resistance Principles of Operation Printhead Operation Page Principles of Operation Printhead Temperature Principles of Operation Spacing Mechanism Principles of Operation Spacing Operation Principles of Operation Head Gap Mechanism Head Gap Setting OperationPage Principles of Operation Ribbon Drive Operation Page Principles of Operation Line Feed Mechanism Change Lever Paper Path Selection LeverPaper Clamp Mechanism Page Rear/Bottom Feed for continuous feed paper Page Principles of Operation Cut Sheet Paper Feed Operation Service Guide ML520/521 Service Guide ML520/521 Service Guide ML520/521 Service Guide ML520/521 Bottom Feed Detection Rear Feed DetectionPage Principles of Operation Support Protector Mechanism Cut Sheet Paper Principles of Operation Automatic Paper LoadPrinciples of Operation Continuous Feed Paper Paper Park Operation Principles of Operation Paper ParkMaintenance & Disassembly General Information Maintenance & Disassembly Maintenance Tools Handbook when the any of the following occur Maintenance & Disassembly Maintenance PrecautionsService Guide ML520/521 Maintenance & Disassembly Preliminary Items Page Perform this procedure Maintenance & Disassembly Printhead AssemblyPage Maintenance & Disassembly Ribbon Protector Perform these procedures 3.2.01 ,53562801 Protector Ribbon Rspl Both B.2.07 Maintenance & Disassembly Gear Case Assembly Maintenance & Disassembly Pull-up Roller Assembly When cleaning, refer to .4 of this Service Handbook Page Installation Maintenance & Disassembly Control Board FjimPage Maintenance & Disassembly Power Supply Assembly Page Perform these procedures 3.2.01 , 3.2.06 , Maintenance & Disassembly Operator Panel PCB LeopPerform these procedures 3.2.01 , 3.2.02 , Maintenance & Disassembly PC Connector56729601 Connector PC HD40 Rspl Both B.2.07 Perform these procedures 3.2.01 , 3.2.02 , 3.2.04 , Page Perform these procedures 3.2.01 , 3.2.06 , 3.2.07 , Maintenance & Disassembly Carriage CableWhen cleaning, refer to .4 of this Service Handbook Maintenance & Disassembly Space RackPage Maintenance & Disassembly Roller/Holder Backup Assembly Maintenance & Disassembly Guide Rail and Adjust Cam Page 51010301 Plate Left Ground Rspl Both B.2.04 Maintenance & Disassembly Left Ground Plate51010201 Plate Right Ground Rspl Both B.2.05 Maintenance & Disassembly Right Ground PlatePerform these procedures 3.2.01 , 3.2.06 , 3.2.07 , 3.2.16 , When lubricating, refer to .5 of this Service Handbook Maintenance & Disassembly Platen AssemblyPage Maintenance & Disassembly Paper Chute Assembly Page Maintenance & Disassembly Line Feed Motor Assembly 56627201 Cord Connection Line Feed Rspl Both B.2.04 50923201 Spring Reset Rspl Both B.2.05 Maintenance & Disassembly Reset SpringMaintenance & Disassembly Idle Gear and Change Lever Page Maintenance & Disassembly Pressure Spring Page Maintenance & Disassembly Carriage Shaft Page Maintenance & Disassembly Leaf Spring Page Maintenance & Disassembly Bottom Paper Sensor Levers Page Maintenance & Disassembly Front Pressure Roller Assembly Page Maintenance & Disassembly Tractor Assembly Page Page Maintenance & Disassembly Main Frame Service Guide ML520/521 Procedure Setup Phase Printhead Gap Modification Phase Parallel Adjustment PhaseVerification Phase Page SEL + FF/LOAD Maintenance & Disassembly Key Combinations DescriptionPrinting the Menu Menu ModeReset Menu to Factory Defaults ProcedureLimited Operation General Information Page Group Setting Maintenance & Disassembly Menu SettingsValid Yes No Page Maintenance & Disassembly Top of Form General Information Setting Top of FormReset the Top of Form to Factory Default Maintenance & Disassembly Paper Park General Information Procedure Continuous Feed to Single SheetProcedure Single Sheet to Continuous Feed Maintenance & Disassembly Tear Feature Vertical Line Spacing Problems Maintenance & Disassembly Forms Tear OffChecking Top of Form with Form Tear Off Activated UsingFactory default Top of Form Setting is 1 inch Cleaning Tools Maintenance & DisassemblyCleaning Cleaning ScheduleLubrication Amounts LubricationLubrication Schedule Lubrication TypesAreas Not Lubricated Return for Service Shipping InstructionsAll Other Returns Failure & Repair Analysis Introduction Service Guide ML520/521 Header Failure & Repair Analysis Firmware Revision IdentificationService Guide ML520/521 Failure & Repair Analysis Problem Lists Mailing Address Failure & Repair Analysis Reporting Methods OkilinkCourse Critique Fax NumberTechnical Service Bulletins OkilinkFaxable Facts Service Guide ML520/521 Alarm Lamp Lights Paper End/Jam Conditions Failure & Repair Analysis Problem CategoriesAlarm Lamp Blinks Fatal Errors Operational ErrorsStart Failure & Repair Analysis Start Here FlowchartThis Service Handbook Failure & Repair Analysis Tips for Preventing Image ProblemsFailure & Repair Analysis Common Problems Always power OFF the printer before you turn the platen knob Page Uneven Print Density Inconsistent Line Feed Smeared PrintDrifting Margin Failure & Repair Analysis Left Margin Drifting Problem Failure & Repair Analysis Fault AlarmsAlar Utility PRO NLQ HSD Menu Blinkin Kin Refer to RAP Page Service Guide ML520/521 Failure & Repair Analysis RAP Index RAP Number Description Start Page Failure & Repair Analysis RAP 02 No Spacing Operation Page Failure & Repair Analysis RAP 03 Printhead Homing Error Page Service Guide ML520/521 Failure & Repair Analysis RAP 05 Printhead Pins Not Firing Failure & Repair Analysis RAP 06 Poor Print Quality Failure & Repair Analysis RAP 07 Ribbon Feed Problem Failure & Repair Analysis RAP 08 Line Feed Problem Page Failure & Repair Analysis RAP 09 Operation Panel Malfunction Failure & Repair Analysis RAP 10 Parallel Interface Problem Page Failure & Repair Analysis RAP 11 Serial Interface Problem Handbook Printer Tests Procedure Page Failure & Repair Analysis Font Test General Information Page Failure & Repair Analysis Serial Interface Loopback Test Loopback Connector ConfigurationPage Failure & Repair Analysis Serial Cable Information Service Guide ML520/521 Service Guide ML520/521 Hex Data Dump ExampleService Guide ML520/521 Layout Diagram Service Guide ML520/521 Failure & Repair Analysis Line Feed Motor Resistance Failure & Repair Analysis Space Motor Resistance Service Guide ML520/521 Chapter a Reference Charts Description Board Designation Section Main Controller BoardOperator Panel Board Chapter a Reference Charts Board Layout Jumpers SwitchesFirmware FusesPage Shift Page Chapter a Reference Charts Power Supply Assembly Function Page Chapter a Reference Charts Space Motor Board Function Page Masked to the MPU Socket is empty Page Service Guide ML520/521 Chapter B Illustrated Parts Listing Format Remember Chapter B Illustrated Parts Listing Current Part NumbersRspl 520 521Both Placing a Parts Order Charts Chapter B Illustrated Parts Listing Overview Refer to CommentsComments Refer to 53067201 2PA4094-7382G1 Cover Access Wide Rspl ROM PCB Leop Service Guide ML520/521 Page Service Guide ML520/521 Page Service Guide ML520/521 Page Page Service Guide ML520/521 N/A Service Guide ML520/521 PCB Lxhi Service Guide ML520/521 PCB Ncsf 52107001 N/A Ribbon Black Consumable Both Chapter B Illustrated Parts Listing ConsumablesTo B.1.02 Comments ReferService Guide ML520/521 Page Okidata P/N Oki-J Description Comments Refer Comments Refer
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