WY 60_Maintenance_Manual 60 Maintenance Manual
WY-60_Maintenance_Manual manual pdf -FilePursuit
WY-60_Maintenance_Manual WY-60_Maintenance_Manual
User Manual: WY-60_Maintenance_Manual
Open the PDF directly: View PDF 
.
Page Count: 136
| Download | |
| Open PDF In Browser | View PDF |
For Service Mllnuilis MAURITRON SERVICES 8 Cherry Tree ROlld, Chlnnor Oxfordshlre, OX9 4Qy' Tel (01844) 351694 Fax (01844) 352554 email:·maurltron@dlal.plpex.com WY-60 Maintenance Manual WYSE - f'- OVERVIEW This maintenance manual contains information on how to service and repair the WY-60 terminal. We assume you are a qualified service technician with previous experience in terminal and computer repair. To take full advantage of this manual, we suggest you read the information in the order presented. HOW TO USE THIS MANUAL This manual is divided into seven chapters and four appendixes. The first chapter provides important information for the tec hn ic ian who ha s never serv ic ed thi s term inal be fore. If you are already familiar with the terminal, the technical information in Appendix A can remind you about the terminal. Here is a summary of this manual: Chapter 1, -General Information," describes the terminal, including information about internal functions, inputloutput (1/0), telecommunications, environmental needs, and operator controls. Chapter 2, "Removal and Replacement Procedures," shows you how to take the terminal apart and put it back together again. Chapter 3, -Troubleshooting," tells you what to look for and how to fix problems with the terminal. It includes a list of tools needed for troubleshooting, a quick reference guide, and a flowchart. Chapter 4, "Adjustments and Alignments," describes power supply and monitor adjustments that control the quality of the display. Chapter 5, "Illustrated Parts List," includes a list of display and keyboard assembly parts. Chapter 6, "Theory of Operations," describes the terminal operation by function. Chapter 1, "Schematics and PCB Assembly Drawings," contains schematic representations of all the terminal's circuits. iii Appendix A, "Specifications," lists the terminal's specifications. Appendix B, "Connector Pin Assignments," lists the signals on each pin of the MODEM and the AUX ports located on the rear panel of the terminal. Appendix C, "Test Connectors," describes how to make diagnostic hood test connectors. Appendix D, "Display Inspection With the Reticle," describes how to check the terminal's display with a special tool, the reticle. REFERENCE MANUALS The following publications provide additional information about the terminal: ~Y-60 User's Guide, Document 880259-02 ~Y-60 Programmer's Guide, Document 880261-01 iv TABLE OF CONTENTS OVERVIEW ................................................... iii 1 GENERAL INFORMATION Introduction ............................................... 1-1 High Level Functional Description .......................... 1-2 Microcontroller ............................................ 1-2 Memory ••••••••••••••••.••••••••••••••.••••••••••••••••••.•• 1-2 Terminal Control ........................................... 1-3 Input/Output Devices ....................................... 1-3 Installation, Operation, and Care .......................... 1-4 2 REMOVAL AND REPLACEMENT PROCEDURES Overview Remov ing Keyboard Remov ing Terminal 3 ................................................... 2-1 and Replacing Assemblies in the Modules .......................................... . 2-3 and Replacing Assemblies in the Module ........................................... . 2-9 TROUBLESHOOTING Before You Start ........................................... Primary Troubleshooting Procedures ......................... Troubleshooting Quick Reference Guide ...................... Troubleshooting Flowchart .................................. Additional Troubleshooting Procedures ...................... 4 3-1 3-2 3-4 3-5 3-12 ADJUSTMENTS AND ALIGNMENTS Before You St3.rt ........................................... Checking Display Specifications ............................ Aligning the Termin3.l Display .............................. Adjusting the Terminal Di.splay ............................. Test Patterns .............................................. v 4-1 4-2 4-5 4-10 4=15 5 ILLUSTRATED PARTS LIST Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Printed Circuit Board Layout and Component Identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Terminal Display Assembly Exploded View . . . . . . . . . . . . . . . . . . . . Keyboard Assemblies Exploded Views . . . . . . . . . . . . . . . . . . . . . . . . . Terminal PCB Components List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Terminal Board Assembly Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . WY-60 Full-Touch Keyboard PCB Components List .............. WY-60 Full-Touch Keyboard PCB Layout . . . . . . . . . . . . . . . . . . . . . . . 316X-Style Keyboard PCB Components List . . . . . . . . . . . . . . . . . . . . 316X-Style Keyboard PCB Layout .. : . . . . . . . . . . . . . . . . . . . . . . . . . . AT-Style Keyboard PCB Components List . . . . . . . . . . . . . . . . . . . . . . AT-Style Keyboard PCB Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Diagnostic Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 5-2 5-3 5-4 5-6 5-13 5-14 5-14 5-17 5-17 5-17 5-17 5-20 THEORY OF OPERATIONS Terminal PCB Logic Components Functional Description ....... Monitor/Power Supply Components Functional Description ..... Keyboard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Additional Functional Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . Raster Scan Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 5-1 6-1 6-6 6-8 6-9 6-13 SCHEMATICS AND PCB ASSEMBLY DRAWINGS Keyboard Keyboard Keyboard Terminal Terminal Keyboard Keyboard Keyboard Terminal PCB PCB PCB PCB PCB PCB PCB PCB PCB Schematic, WY-60 ASCII . . . . . . . . . . . . . . . . . . . . . . . . Schematic, AT-Style . . . . . . . . . . . . . . . . . . . . . . . . . . . Schematic, 316X-Style . . . . . . . . . . . . . . . . . . . . . . . . . Schematic, Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Schematic, Monitor/Power Supply ............... Assembly Drawing, WY-60 ASCII ................. Assembly Drawing, AT-Style .................... Assembly Drawing, 316X-Style .................. Assembly Drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-3 7-5 7-7 7-9 7-13 7-15 7-17 7-19 7-21 APPENDIXES A B C D Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ··· Connector Pin Assignments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Test Connectors ....... : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Display Inspection with the Reticle ................... A-1 B-1 C-1 D-1 INDEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1 vi LIST OF FIGURES 1 -1 1-2 Terminal Installed .................................... 1-4 User Controls .............................. ··········· 1 -5 Terminal Modules ..................................... . Keyboard Styles ...................................... . ASC II Keyboard Assembl y .............................. . 316X- and AT-Style Keyboard Assembly ................. . Removing the Terminal Enclosure ...................... . Replacing the Fuse ................................... . Remov ing the Terminal PCB ............................ . Removing the CRT/Yoke Assembly ....................... . Re plac ing the Yoke ......................... Discharging the Anode Before Removal ................. . 2 -11 Discharging the Anode Before Installation ............ . 2-1 2-2 2-3 2-4 2-5 2-6 2-7 2-8 2-9 2-10 0 • 0 ••••••• 0 2-2 2-3 2-5 2-8 2-9 2-10 2-12 2-14 2-15 2-17 2-18 3-6 3-1 Troubleshooting Flowchart ..... 4-1 4-2 4-3 4-8 4-5 4-6 4-7 Power Supply Component Layout Adj us tmen t Loca t ions ................................. . Yoke Lock on the CRT Neck ........................... .. Centering Rings ................. o. Display Magnets ............................... Pa t tern M ............................................ . Pattern 0 ............................................ . 5-1 5-2 5-3 5-4 5-5 5-6 5-7 Sample PCB ........................................... Terminal Display Assembly Exploded View .............. Keyboard Assemblies Exploded Views ................... Terminal Board Assembly Layout ....................... WY-60 ASCII Keyboard PCB Layout ...................... 316X-Style Keyboard PCB Layout ....................... AT-Style Keyboard PCB Layout ......................... 5-2 5-3 5-4 5-14 5-16 5-18 5-20 6-1 Terminal PCB Logic Circuitry Functional Block Diagram ........................................ . 6-2 Monitor/Power Supply Circuitry Functional Block Diagram ........................................ . 6-7 Keyboard Block Diagram ............................... . 6-8 4-4 6-2 6-3 7-1 7-2 7 -3 7 -4 7-4 7-5 7 -6 7-7 7-8 0 .0 ••••••••••••• ••••••••••• 0 0 0 •••• •••• ••••••••••• 0 0 0 •••• ••••• • ••••••• 0 ••••••• . . . . . . . WY-60 ASCII Keyboard PCB Schematic ................... . AT-Style Keyboard PCB Schematic ...................... . 316X-Style Keyboard PCB Schematic .................... . Terminal PCB Schematic (Logic) ....................... . Term inal PCB Sc hema t ic (Moni tor /Power Suppl y) ........ . WY-60 ASCII Keyboard PCB Assembly Drawing ............ . AT-Style Keyboard PCB Assembly Drawing ............... . 316X-Style Keyboard PCB Assembly Drawing ............. . Terminal PCB Logic Assembly Drawing .................. . vii 4-10 4-12 4-13 4-13 4-15 4-16 7 -3 7-5 7-7 7-9 7-13 7-15 7-16 7-17 7-18 . ... ~ ·o:D~"""';"'··---·- ___ IIlliJ.f"Oi~tt:UIo..iA""__ .. LIST OF FIGURES, Continued B-1 D-1 D-2 D-3 Pin Numbers (MODEM and AUX Ports) ..................... B-1 Video Inspection Reticle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D-1 Checking Width and Height .. ; . . . . . . . . . . . . . . . . . . . . . . . . . . D-3 Checking Straightness, Pincushioning, Centering, and Vertical Linearity . . . . . . . . . . . . . . . . . . . . . D-4 LIST OF TABLES 3-1 3-2 3-3 Module Level Troubleshooting Quick Reference Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5 Terminal Installation Checklist ....................... 3-13 Terminal PCB Circuit Isolation Jumpers . . . . . . . . . . . . . . . . 3-16 4-1 4-2 Display Problems and Their Adjustments ................ 4-9 Screen Areas Affected by Display Magnets . . . . . . . . . . . . . . 4-14 5-1 5-2 5-3 5-4 5-5 5-6 Reference Designator Letters . . . . . . . . . . . . . . . . . . . . . . . . . . Terminal PCB Components List . . . . . . . . . . . . . . . . . . . . . . . . . . WY-60 ASCII Keyboard PCB Components List .............. 316X-Style Keyboard PCB Components List ............... AT-Style Keyboard PCB Components List ................. Diagnostic Self-Test Connectors . . . . . . . . . . . . . . . . . . . . . . . 6-1 6-2 Clock Rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4 8051 Port Assignments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-9 B-1 MODEM Port Connector Pin Assignments (DTE) ............ B-1 Typical Modem Pin Assignments . . . . . . . . . . . . . . . . . . . . . . . . . B-2 AUX Port Connector Pin Assignments (DCE) .............. B-2 B-2 B-3 viii 5-2 5-7 5-15 5-17 5-19 5-21 1 GENERAL INFORMATION Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1 High Level Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2 Microcontroller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2 Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2 Terminal Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3 Input/Output Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3 CRT Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3 Communications Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3 Keyboard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3 Installation, Operation, and Care . . . . . . . . . . . . . . . . . . . . . . . . . . Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Care . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4 1-4 1-5 1-6 INTRODUCTION This versatile, full-function ASCII terminal includes the following features: o Choice of three different keyboRrds o Up to seven pages of display memory o Choice of 26- or 44-line by 80- or 132-column display, split screen capability and selectable status lines o Hidden character display attributes that can be combined with double-high/double-wide line attributes; nonhidden attribute modes o Seven predefined character sets and 512 user-definable characters o Fifteen operating modes with personalities characteristic of other terminals, including PC and PC/AT terminal modes o Bidirectional, interchangeable communications interfaces 1-1 with o WyseWorks desktop accessories o Wyseword WordStar key definitions The terminal consists of a display console and a detachable keyboard. A user enters information for display from the keyboard. The terminal contains all of the electronics that support the display and keyboard. In addition to the cathode ray tube (CRT) and keyboard, the terminal contains two independent communications interfaces. Peripherals, including a hard-copy printer or plotter, can be attached to the terminal through the interface connectors on the rear panel. The component parts are organized around and controlled by the microcontroller. The microco~troller controls all internal data manipulation and processing functions. HIGH LEVEL FUNCTIONAL DESCRIPTION The terminal consists of a microcontroller and related logic, a CRT controller and associated control logic, a gate array, input/output (I/O) devices, monitor and power supply circuitry, and a CRT. All circuitry is mounted on a single printed circui t board (PCB), the terminal PCB. The microcontroller controls all basic functions. MICROCONTROLLER The heart of the terminal, the 8051 microcontroller, is an 8-bit, single-component microcontroller that has 128 bytes of random access memory (RAM), 32 I/O lines, three 16-bit counter/timers, a full-duplex universal asynchronous receiver/transmitter (UART), and integral interrupt and clock circuitry. MEMORY The terminal memory consists of EEPROM, RAM, EPROM, and ROM. The terminal EEPROM is the X2404, which stores all user selected setup parameters. Terminal RAM includes the Character RAM, the Attribute RAM, and the Font RAM. In hidden attribute mode, the Character RAM holds a character for each character cellon the screen. The Attribute RAM holds an attribute for each character cellon the screen. The Font RAM holds four predefined character sets and that may include additional user-defined characters. Terminal ROM includes the Code ROM, which holds the program code that operates the terminal, and the ROM internal to the 8051 that supports the Code ROM. 1-2 TERMINAL CONTROL Terminal control components include the S051 microcontroller described above and the 2672 programmmable video timing controller (PVTC). The 2672 controls vertical and horizontal timing, consecutive addressing for the display memory, the microcontroller-display buffer interface, and consecutive addressing of row buffers. The PVCT controller reads displayed characters and attributes from their respective RAMs on a DMA basis, sending this information to the gate array. The gate array generates the video signals that control the display. Functions of the terminal firmware include keyboard scanning, programming the video controller, data transfer to and from the communication ports, and data manipulation. INPUT/OUTPUT DEVICES 1/0 devices consist of a CRT display, two communications interfaces, and a keyboard. CRT Display The terminal has a 14-inch, flat-screen CRT. It displays 26 or 44 rows of characters and So or 132 columns. Available phosphor colors for the CRT include green, amber, and white. Communications Interfaces The terminal has two asynchronous serial interfaces that conform with the EIA standard RS-232C. Data rates are set independently for both interfaces. These parameters are operator controlled and are defined in "Setup Parameters" in the User's Guide. The MODEM interface can communicate at data rates up to 3S.4K bits per second (bps). The AUX interface can communicate at data rates up to 19.2K bps. Keyboard The terminal is available with three keyboards: the WY-60 ASCII keyboard, an 316X-style keyboard, and an AT-style keyboard. Each has a standard four-wire interface with the terminal. All keys are momentary action key switches. The microprocessor periodically scans the keys, checking for key closures. Figure 2-2 in Chapter 2 shows the keyboards. You can find add it ional in fo rm a tion ab out the ke yboard s in Cha pte r 6, "Theo ry of Operations" and Chapter 7, "Schematics." . 1- 3 INSTALLATION, OPERATION, AND CARE Some problems you may see can be caused when users don't install, operate, or care for the terminal correctly. The following paragraphs are a quick overview discussing correct installation, operation, and care. Installation Correct installation meets the following requirements: o Terminal rests on a horizontal, vibration-free surface. o Screen avoids direct sunlight. o Room lighting is not abnormally bright. o Terminal is located away from strong magnetic fields. o Room temperature never exceeds 45 degrees Celsius (113 degrees F). o Terminal location allows three inches clearance around and above t he term inal. o Keyboard is correctly connected in keyboard socket. o RS-232C communication'cable is correctly connected to the terminal and the computer. o Power cord is correctly connected to the terminal and a power source. Figure 1-2 shows the correct terminal connections. Figure 1-2 Terminal Installed Power Cord 1-4 Operation Two areas of operation are important to understand: con trols and setup. user User controls--Figure 1-3 shows three user controls: the power switch, brightness slideswitch, and the keyboard. Figure 1-3 User Controls Brightness Slideswitch Power Switch Keyboard ~~ The power switch is on the right side of the terminal. the back of the switch turns AC power on. Pressing The brightness slideswitch is located on the lower-right corner of the front bezel. Sliding the switch to the right increases the display brightness; sliding it to the left decreases the brightness. Plugging the keyboard cable connector into the keyboard connector jack on the left side of the terminal enables the user to control the display with the keyboard. SetUp--When a user turns the power on, the terminal executes an internal self-test. When the self-test finishes and the CRT is warm (approximately 30 seconds), the cursor appears in the upper left-hand corner of the display. The user can operate the terminal or enter setup mode to change certain operating values based on the parameters controlled in setup. To check the parameters, press both the SHIFT and SETUP keys. The first level of parameters appears across the bottom of the screen. To examine the other parameter menus, press function keys F1 through F10. Each time you press a different key, you can see a different menu. 1-5 To change the parameters, follow these steps: 1. Enter setup mode by pressing the SHIFT and SETUP keys. (Press the SHIFT and SYS REQ keys on the AT-style keyboard.) 2. Press one of the designated function keys (F1 through F10). The menu assigned to that function key will appear on the screen. 3. Press the cursor keys until the specific parameter to be changed is highlighted. 4. Press the SPACEBAR to advance the parameter to the specific setting desired. 5. Press the cursor keys as required to advance to the next parameter to be changed. 6. To leave setup mode, either press the SHIFT and SETUP keys or the F10 key. In all levels other than the top setup level, you must press these keys twice. The terminal is now operational using the parameters defined in the setup mode. See the ~Y-60 User's Guide for more comprehensive setup instructions. CARE You may find that the terminal needs to be cleaned when you've finish servicing it. The screen should be cleaned with a soft, lint-free cloth. Apply a safe cleaner to the cloth, not directly to the screen. Caution--Don't ever clean the screen with chemical substances, abrasives, or commercial glass cleaners that contain alcohol. 1-6 2 REMOVAL AND REPLACEMENT PROCEDURES Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1 Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2 Required Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3 Removing Keyboard ASCII ASCII ASCII 316X316X316X- and Replacing Assemblies in the Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Keyboard Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Keyboard Cable Replacement . . . . . . . . . . . . . . . . . . . . . . . . Keyboard PCB Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . and AT-Style Keyboard Replacement . . . . . . . . . . . . . . . . . and AT-Style Keyboard Cable Replacement ........... and AT-Style Keyboard PCB Replacement . . . . . . . . . . . . . Removing and Replacing Assemblies in the Terminal Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Remov ing the Terminal Enclosure . . . . . . . . . . . . . . . . . . . . . . . . . Replacing the Fuse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Removinng and Replacing the Terminal PCB ................ Removing and Replacing the CRT/Yoke Assembly . . . . . . . . . . . . Remov ing and Replac ing the Yoke . . . . . . . . . . . . . . . . . . . . . . . . . Replacing the Terminal Enclosure . . . . . . . . . . . . . . . . . . . . . . . . Discharging the Anode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3 2-4 2-5 2-6 2-7 2-7 2-7 2-9 2-9 2-10 2-11 2-13 2-15 2-16 2-16 OVERVIEW This chapter explains how to remove and replace assemblies and components in both terminal modules. For purposes of orientation, "front" is the monitor face, and "back" is the rear panel and power cord location. The terminal consists of two major modules (see Figure 2-1): o Terminal The terminal module includes the CRT/yoke assembly and the terminal PCB. The terminCll PCB holds all control logic, power supply circuitry, and the circuitry to amplify and display horizontal, vertical, and video signals on the CRT screen. o Keyboard The keyboard module includes the keyboard PCB and the keyboard cable. 2-1 Figure 2-1 Terminal Modules Safety termin~l contains high voltage. Don't attempt to service the terminal without taking all the precautions necessary to work with high voltage, including the following: Warning--This o If you must open the terminal for any reason, turn off the power, disconnect any communications cables, and unplug the terminal. o Remove any jewelry, especially on hands and wrists. o Avoid wearing clothing that holds a static charge. o Use only insulated or nonconductive tools. o Whenever you disconnect the anode lead from the anode, mak8 sure to ground the ~node as directed in "Discharging the Anode." o If you need to remove or replace the CRT/yoke assembly, remember that it can implode if you drop it or break the neck. The flying glass can injure anyone within a radius of six to ten feet. 2-2 Required Tools Before you remove or replace any assemblies in the terminal, make sure you have the tools and materials listed below. o No. 0 Phillips screwdriver o No. 2 Phillips screwdriver o Insulated flat-blade screwdriver o Alligator clips o Digital multimeter (or voltmeter) o Nonscratch mat or surface o Fuse puller or small flat-blade screwdriver REMOVING AND REPLACING ASSEMBLIES IN THE KEYBOARD MODULES The terminal has three keyboard options: the WY-60 ASCII keyboard, the 316X-style keyboard, and the AT-style keyboard. See Figure 2-2 if you need to identify your keyboard. Removal and replacement instructions for the ASCII keyboard are first, followed by another set of instructions for the other keyboard styles. Each set of instructions describes procedures to remove and replace the keyboard, keyboard cable, and keyboard PCB. Figure 2-2 Keyboard Styles WY-60 ASCII Keyboard Layout 2-3 3161X-Style Keyboard Layout AT-Style Keyboard Layout ASCII Keyboard Replacement Tools required: None Follow these steps to replace the keyboard (see Figure 2-3): 1. Turn the terminal off. 2. Press the keyboard cable connector tab and pull the keyboard cable out of the keyboard socket on the side of the terminal. 3. Plug the new keyboard into the terminal keyboard socket. 2-4 Figure 2-3 ASCII Keyboard Assembly L~ PCB A,,,mbly Top Cover For Service Manuale MAURITRON SERVICES 8 Cherry Tree Road, Chlnnor Oxford.hlre, OX9 4Qy' Tel (01844) 351694 Fax (01844) 352554 ASCII Keyboard Cable Replacement emall;-maurltron@dlal.plpex.com Tools required: o No.2 Phillips screwdriver To replace the keyboard cable (see Figure 2-3): 1. Turn the terminal off. 2. Press the keyboard cable connector tab and pull the cable out of the keyboard socket on the side of the terminal. 3. Unscrew the four Phillips screws on the bottom of the keyboard. Remove the bottom cover. 4. Unscrew the two Phillips screws on the bottom of the exposed keyboard PCB, holding the PCB to the top cover. 2-5 Turn it over. 5. Lift the keyboard PCB out of the top cover. 6. Disconnect the keyboard cable from the keyboard cable conn ec tor on t he PCB. 7. Connect the new keyboard cable at the keyboard cable connector on the keyboard PCB. 8. Fit the keyboard PCB into the top cover, making sure to fit the keyboard cable into its special slot. Replace the screws that secure the PCB to the top cover. 9. Replace the bottom cover and screws. 10. Plug the free end of the keyboard cable into the terminal keyboard socket. ASCII Keyboard PCB Replacement Tools required: o No.2 Phillips screwdriver To replace the keyboard PCB (see Figure 2-3): 1. Turn the terminal off. 2. Press the keyboard cable connector tab and pull the keyboard cable out of the keyboard socket on the side of the terminal. 3. Unscrew the four Phillips screws on the bottom of the keyboard. Remove the bottom cover. 4. Unscrew the two Phillips screws on the bottom of the exposed keyboard PCB, holding the PCB to the top cover. 5. Lift the keyboard PCB out of the top cover. 6. Disconnect the keyboard cable connector J1 from the keyboard PCB. 7. Reconnect the keyboard cable connector at Jl on the new keyboard PCB. 8. Fit the keyboard PCB into the top cover, making sure to fit the keyboard cable into its special slot. Replace the screws that secure the PCB to the top cover. 9. Replace the bottom cover and screws. 10. Plug the free end of the keyboard cable into the terminal ke yboa rd soc ket. 2-6 Turn it over. 316X- and AT-Style Keyboard Replacement Tools required: None To replace the keyboard (see Figure 2-4), follow these steps: 1. Turn off the terminal. 2. Press the keyboard cable connector tab and pull the keyboard cable out of the keyboard. 3. Plug the keyboard cable into the new keyboard's connector. 316X- and AT-Style Keyboard Cable Replacement Tools required: None To replace the keyboard cable (see Figure 2-4), s te ps : follow these 1. Turn the terminal off. 2. Press the keyboard cable connector tab and pull the keyboard cable out of the keyboard. 3. Press the other keyboard cable connector tab and pull the keyboard cable out of the left side of the terminal. 4. Insert one end of the new keyboard cable into the keyboard connector. Insert the other end into the terminal keyboard socket. 316X- and AT-Style Keyboard PCB Replacement Tools required: o No. 0 Phillips screwdriver o No.2 Phillips screwdriver To replace the keyboard PCB (see Figure 2-4), follow these steps: 1. Turn off the terminal. 2. Unpl ug the keyboard cable from the keyboard. 3. Turn the keyboard over and remove the six No.2 Phillips screws that attach the keyboard bottom cover to the keyboard. 4. Lift off the keyboard bottom cover. 2-7 Figure 2-4 316X- and AT-Style Keyboard Assembly PCB Assembly Top Cover Keyboard Cable 5. Remove the No. 0 Phillips screw beneath the SPACEBAR that holds the keyboard top cover to the PCB assembly. 6. Unscrew the three No. 0 Phillips screws and washers that hold the keyboard ESD shield on the keyboard PCB. 7. Lift the PCB assembly out of the keyboard cover. 8. Cover the under side of the new keyboard PCB with the keyboard ESD shield. Replace the screws and washers. Tighten. 9. Fit the new keyboard PCB assembly back into the keyboard top cover. 10. Replace the No. 0 Phillips screw that holds the PCB assembly in place. 11. Reatt3ch the bottom cover of the keyboard assembly. 12. Plug the keyboard cable back into the terminal. 2-8 REMOVING AND REPLACING ASSEMBLIES IN THE TERMINAL MODULE This section describes removing and replacing the terminal enclosure, the fuse, the terminal PCB, and the CRT/yoke assembly. It also describes how to discharge the CRT anode. Removing the Terminal Enclosure Tool required: o No.2 Phillips screwdriver To remove the terminal enclosure (see Figure 2-5), follow these s te ps : 1. Remove all cables and power cords from the rear of the terminal. 2. Rest the display face of the terminal on a nonscratch surface. Figure 2-5 Removing the Terminal Enclosure Nonscratch Surface 2-9 , 3. Disconnect the keyboard cable on the left side of the terminal enclosure. 4. Remove the two No.2 Phillips screws from the rear panel of the terminal enclosure. 5. Remove the two No.2 Phillips screws from the bottom of the terminal enclosure, next to the back bezel. 6. Lift off the terminal enclosure. Replacing the Fuse Tool required: o Fuse puller or screwdriver The terminal has a BEL5MT2 fuse, rated 2 amps, 125 volts (international rating is 1.6 amps, 250 volts). See Figure 2-6 for the fuse location on the terminal PCB. To check or replace the fuse, follow these steps: See Figure 2-5. 1. Remove the terminal enclosure. 2. Use a fuse puller to remove the fuse. Figure 2-6 Replacing the Fuse Fuse Puller or Screwdriver 2-10 3. Check the fuse. If the fuse is broken or blackened, new fuse into the fuse socket. push a If the fuse is good, push it back into the fuse socket. 4. Replace the terminal enclosure (see "Replacing the Terminal Enclosure" for instructions). Removing and Replacing the Terminal PCB Tools required: o No.2 Phillips screwdriver o Flat-bladed screwdriver o Alligator clips To remove the terminal PCB (see Figure 2-7), follow these steps: 1. Unplug the terminal and remove the shielded RS-232 communication cable. 2. Remove the terminal enclosure. 3. Slide the barrier plates mounted on either side of the back bezel out from under the restraining tabs. 4. Leaving the terminal on its face, pull the back bezel off the terminal frame. 5. Discharge the anode (see "Discharging the Anode" for instructions) . 6. Disconnect the anode lead. 7. Disconnect the yoke harness connector, P201, terminal PCB. from the Warning--Handle the CRT neck carefully. If you break it, flying glass can injure anyone within a radius of six to ten feet. 8. Disconnect the tube socket from the neck of the CRT. 9. Unscrew the two Phillips No.2 screws that secure the grounding wires to the CRT wire frame. Caution--Don't remove the Phillips screws directly underneath the rear panel on the terminal PCB. They fasten the rear panel to the terminal PCB. 10. Remove the four plastic studs that secure the ESD shield to the back of the terminal PCB. 2-11 11. Loosen the three screws that hold the ESD shield in place. 12. Remove the ESD shield. 13 . Lo 0 sen the rem a i n in g t h r e e No. 2 Phi 11 ips s c r e wson the underside of the terminal PCB. 14. Lift the terminal PCB up and out. Figure 2-7 Removing the Terminal PCB Back Bezel Barrier Plate Restraining Tab Filament Harness Grounding Wires / ~ &J/ ~~~ 1 2-12 Plastic Studs 4 To replace the terminal PCB, follow these steps: 1. Posi tion the ESD shield on the bac k of the term inal PCB. 2. Replace the four plastic studs that secure it. 3. Position the terminal PCB in its slot in the bezel. Make sure the lever of the brightness potentiometer fits into the brightness slidecontrol on the bezel. 4. Tighten the three screws that secure the terminal PCB to the wire frame. 5. Replace the ESD shield, then tighten the three remaining screws. 6. Reconnect the grounding wires to the wire frame. 7. Reconnect the yoke harness to P201 on the terminal PCB. Warning--Handle the CRT neck carefully. If you break it, flying glass can injure anyone within a radius of six to ten feet. 8. Reconnect the filament harness to the CRT neck. 9. Discharge the anode on the CRT (see "Discharging the Anode") . 10. Reconnect the anode lead. 11. Replace the back bezel and both barrier plates. 12. Replace the terminal enclosure and keyboard. Removing and Replacing the CRT/Yoke Assembly Tools required: o No.2 Phillips screwdriver o Flat-bladed screwdriver o Alligator clips To remove the CRT/yoke assembly (see Figure 2-8), follow these steps: 1. Remove the terminal enclosure, keyboard cable, back bezel, and barr i er pla tes. 2. Remove the terminal PCB and insulation sheet. 2-13 3. Unscrew the four No.2 Phillips screws securing the wire frame to the front bezel. Warning--Handle the CRT carefully. If you break it, flying glass can injure anyone within a radius of six to ten feet. 4. Lift up the wire frame, and remove the CRT/yoke assembly. Figure 2-8 Removing the CRT/Yoke Assembly Tension Band Tightening Screw CRT IYoke Assembly --~ To replace the CRT/yoke assembly, follow these steps: 1. Discharge the anode on the new CRT. Warning--If you are replacing the same CRT/yoke assembly, you still need to discharge the anode. A CRT left standing for any length of time can develop a charge from the air, and will need to be discharged again. 2. Place the assembly in the front bezel. Make sure the anode faces the keyboard connector jack on the terminal PCB. 3. Fit the wire frame back into the bezel. 2-14 4. If necessary, loosen the tension band tightening screw. 5. Replace the four No.2 Phillips screws that secure the assembly to the wire frame. Tighten. 6. Replace the terminal PCB and insulator sheet. 7. Make sure the tension band is tight. it. 8. Replace the back bezel, barrier plates, and keyboard cable. 9. Replace the terminal enclosure. If it isn't, tighten Removing and Replacing the Yoke Tools required: None To remove the yoke, follow these steps: 1. Remove the CRT/yoke assembly from the terminal. 2. Loosen the yoke lock on the neck of the CRT (see Figure 2-9). 3. Remove t he yoke. Figure 2-9 Replacing the Yoke Yoke Lock Yoke ! + - - Crt Neck Anode 2-15 To replace the yoke, follow these steps: Warning--Before you reattach the yoke assembly, you must discharge the anode. A CRT left standing for any length of time will develop a charge from the air, and need to be discharged again. 1. Position the yoke on the neck of the CRT (see Figure 2-9). 2. Tig h t en t he yo ke 1 oc k . 3. Replace the CRT/yoke assembly in the terminal. Replacing the Terminal Enclosure Tool required: o No.2 Phillips screwdriver To replace the terminal enclosure, follow these steps: 1. With the terminal face on a nonscratch surface, reseat the enclosure over the wire frame into the back bezel. 2. Replace the two No. 2 Phillips screws on the rear of the terminal enclosure. Tighten. 3. Replace the two No.2 Phillips screws on the bottom of the term inal. Tigh ten. Discharging the Anode Tools required: o Insulated flat-blade screwdriver o Alligator clips We have written specific warnings throughout this chapter about discharging the anode on the side of the CRT. If you have never discharged the anode, or need a review, follow these instructions. To discharge the CRT anode before removal (see Figure 2-10), follow these steps: 1. Turn off the terminal and unplug it from its power source. 2. Remove the terminal enclosure. 3. Ground the shaft of an insulated flat-bladed screwdriver to the terminal wire frame with alligator clips. 2-16 Figure 2-10 Discharging the Anode Before Removal Aligator Clips Terminal Chassis 4. Slip the blade between the anode cap and the anode. Touch the blade to the wire anode leads under the cap. Listen for a po ppi ng or crac kl ing so und. 5. Remove the anode lead. To discharge the anode before installation (See Figure 2-11), follow these steps: 1. Ground the shaft of an insulated flate-bladed screwdriver. 2. Touch the blade of the screwdriver to the anode. a popping or crackling sound. 3. Install the CRT. 2-17 Listen for Figure 2-11 Discharging the Anode Before Installation Ground Insulated Flat-Blade Screwdriver 2-18 3 TROUBLESHOOTING 3-1 Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1 Required Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2 Before You Start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2 Prepar ing the Terminal for Troubleshooting .............. 3-2 Power-On Self Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3 Diagnostic Self-Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3 Back-to-Back Diagnostic Self-Test . . . . . . . . . . . . . . . . . . . . . . . 3-4 Primary Troubleshooting Procedures . . . . . . . . . . . . . . . . . . . . . . . . . Troubleshooting Quick Reference Guide . . . . . . . . . . . . . . . . . . . . . . 3-4 Troubleshooting Flowchart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5 3-7 No Video/No Beep . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dim Video . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Other Video Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fails Self-Test of Diagnostic Tests . . . . . . . . . . . . . . . . . . . . . Miscellaneous Symptoms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10 3-10 3-10 3-12 Additional Troubleshooting Procedures . . . . . . . . . . . . . . . . . . . . . . 3-12 Installation Checklist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Checking for Continuity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Power Supply Check on the Terminal PCB . . . . . . . . . . . . . . . . . . Checking the Keyboard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Isolating Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-14 3-14 3-15 3-15 3-13 BEFORE YOU START Read the following safety information carefully before you attempt to troubleshoot your unit. Safety Warning--This terminal contains high voltage. Don't attempt to service the terminal without taking all the precautions necessary for working with high voltage, including the following: o If you must open the terminal for any reason, turn off the power, disconnect any communication cables, and unplug the terminal. o Remove any jewelry, especially from your han1s and wrists. o Avoid wearing clothing that holds a static charge. 3-1 o Use only insulated or nonconductive tools. o Whenever you disconnect the anode from the anode lead, make sure to discharge the anode as directed in Chapter 2. o If you need to remember that the neck. The radius of six remove or replace the CRT/yoke assembly, the CRT can implode if you drop it or break flying glass can injure anyone within a to ten feet. Required Tools Before you start to repair in the terminal, make sure you have the tools and materials listed below. o No.2 Phillips screwdriver o 3/16-inch flat-bladed screwdriver o Digital multimeter (DMM) or a voltmeter o Test connectors for the MODEM and AUX ports (See Appendix C for instructions to make them or Chapter 5 for ordering in forma tion . ) o Nonconductive video alignment tool o Tie-wraps and diagonal cutters to cut tie-wraps PRIMARY TROUBLESHOOTING PROCEDURES You should begin troubleshooting by preparing the terminal properly and running the Power-On Self-Test and the Diagnostic Self-Tests. These tests generate error messages, which are identified in the "Fails Power-on or Diagnostic Self Tests" section of Figure 3-1. Preparing the Terminal for Troubleshooting To prepare the terminal for troubleshooting, follow these steps: 1. Turn off the terminal. 2. Disconnect the computer's communication cables. 3. Unpl ug the power cord from its power sourc e. 4. Remove the terminal bucket and back bezel. 5. Plug the power cord back into it's power source. 6. Turn on the terminal. 3-2 Power-on Self-Test The power-on self-test checks th~ terminal's random access memory (RAM), read-only memory (ROM), electrically eraseable read-only memory (EEROM), and external communication ports. Each time you turn the terminal on, the power-on self-test occurs. If the test detects an error, an error message appears on the display. The "Fails Power-on or Diagnostic Self-Tests" section in Figure 3-1 identifies these errors. If any of these messages appear, replace or troubleshoot the terminal PCB. Diagnostic Self-Test The terminal diagnostic self-test starts in setup mode. This procedure includes communications circuitry tests, read/write tests, and row buffer tests. Two special test connectors allow the diagnostic test to function (see Appendix C for connector definitions or Chapter 5 for ordering information). After you start it, the diagnostic test continues to run until you stop it. If the test detects an error, an error message appears in the lower right-hand corner of the screen (see "Fails Power-on or Di3.gnostic Self-Tests" in Figure 3-1). Follow these steps to start the diagnostic self-test: 1. Turn the term inal off. 2. Detach any communications cables on the back of the terminal. 3. Attach the test connectors to the MODEM and AUX ports on the rear of the terminal. Note--See Appendix C for a description of these test connectors and instructions to make them. See Chapter 5 to ord er them. 4. Turn the terminal on. 5. Hold the SHIFT key, then press the SETUP key. 6. Press the F2 key. setup menu. 7. Use the cursor keys to highlight the TEST:OFF field. 8. Press the SPACEBAR. 9. Press the F10 key, then CUSOR RIGHT, will see a flashing test pattern. 10. If the test stops, the terminal beeps,·and a letter or number appears on the screen go to the "Fails Power-on or Diagnostic Self-Tests" section of Figure 3-1. Look for to the TEST:OFF field in the This toggles the TEST field ON. 3-3 then F10 again. You Note--To fully test the terminal, let the diagnostic self-test run five minutes. 11. If you see an error message, replace or troubleshoot the terminal PCB; if you don't see an error, press the SPACEBAR, then the SETUP key. 12. Turn the terminal off. Remove the test connectors, and reattach the communications cables. Back-to-Back Diagnostic Self-Test The back-to-back diagnostic self-test also starts in setup mode. This test checks communications circuitry. A special test harness allows the test to function (see Appendix C for harness definition or Chapter 5 for ordering information). After you start it, the back-to-back diagnostic test continues to run until you stop it. If the test detects an error, an error message appears in the lower right-hand corner of the screen (see "Fails Power-on or Diagnostic Self-Tests" in Figure 3-1). To start the back-to-back diagnostic self-test, follow the same steps as for the diagnostic self-test (previous page), with the exception of step 3: 3. Attach the test harness to the MODEM and AUX ports on the rear of the terminal. Note--See Appendix C for a description of the test harness and instructions to make it. See Chapter 5 to order it. TROUBLESHOOTING QUICK REFERENCE GUIDE Table 3-1 is a troubleshooting reference guide. Once you discover the major symptoms, this table can quickly direct you to the most likely problem area. However, don't automatically replace the suggested modules until you've studied the problem or checked related details in the troubleshooting flowchart. 3-4 Table 3-1 Module-Level Troubleshooting Quick Rererence Guide Symptom Possible Problem Area(s) No display Terminal PCB, CRT/yoke assembly Poor display quality Adjustments, terminal PCB Wrong size display Crooked Too bright Not in foe us Adjustments, terminal PCB, yoke F3.ils self-test Terminal PCB F3.ils diagnostic test Terminal PCB, wrong diagnostic setup, faulty test connectors Inoperative keys Keyboard, terminal PCB, keyboard cable Can't communicate with computer Setup parameters, terminal PCB, communication cable Letters or error codes on the screen Terminal PCB TROUBLESHOOTING FLOWCHART Read the troubleshooting flowchart and match the symptoms with the suggested solutions. Use the schematics and assembly drawings in Chapter 7 to help you interpret this flowchart. 3-5 Figure 3-1 Troubleshooting Flowchart, page 1 of 7 Start Prepare terminal for troubleshooting 3-2 Symptom: No beep 3-7 Symptom: No v ideo 3-7, 3-10 Symptom: Dim video 3-10 Symptom: Single line of video on screen 3-10 Symptom: roll Vertical 3-10 Symptom: no video Raster, 3-10 Symptom: Letter on screen before diagnostic self-test 3-10 Run diagnostic self-test 3-3 Letter Symptom: on screen after diagnostic self-test 3-10 Symptom: quality Poor display Ke yboa rd not Sym ptom: operating Symptom: problems Communication Chapter 4, Per fo rm full alignment 3-12 3-12 Characters Sympt8rn: scrambled or degraded, dots missing 3-12 Symptom: Characters don't appear on the screen 3-12 End 3-6 Figure 3-1 Troubleshooting Flowchart, page 2 of 7 No Video/No Beep 1. Check power cord, on/off swi tch, fuse Check for continuity and correct connections. Make sure J102 is set for the correct line voltage. 2. Check beeper B 1 and surrounding circuitry 3. Check brightness Check the brightness slideswitchj perform the brightness alignment. (See "Brightness" in Chapter 4.) 4. Check all power supplies +5V, U1-40, (U1-20 is ground) +12V, U27-14 (U27-7 is ground) -12V, U27-1 (U27-7 is ground) If one of the power supply vol tages is out of tolerance, use the schematics found in Chapter 7 to trace and fix the problem. 5. Check tube filament Is it glowing? tube socket: If not, check the Is the socket plugged in? Are any of the CRT's pins bent? Check the continuity between the socket and its board connections. 6. Check video transistors Q402, Q401, Q403, Q404. If any aren't operating correctly, replace. 7. Check U20 Look for video output: Video 0, U20-14 Video 1, U20-15 Check both lines with an oscilloscope, you should see toggling activity on both. If you don't, check these areas: Dot Clock at U20-1. Look for a 50 percent duty cycle at 26.58 or 39.71 MHz. If the waveform is missing or incorrect, re~ove U20 and tro ubl eshoo t the dot cl oc k. Chec k U21 and the surrounding circuitry. Then check U20-1 again. 3-7 Figure 3-1 Troubleshooting Flowchart, page 3 of 7 No Video/No Beep, Continued 7. Chec k U20 (continued) If the waveforem is correct, check the character clock output at U20-8. Look for 2.658 or 4.4122 MHz. If the output is missing, replace U20. Check for shorts on the video output lines: U20-14, U20-15, Q403, Q404, R25, and R26. Are these lines open? Check the video blank line, U20-9. Check HSYNC: Is U20-7 toggling? Look for 26.58 KHz. Is the line open or short? Check R201. Is HSYNC present from the video controller at U20-10? If the signal is present, replace U20. If the signal isn't present, check U19-9. Check MBC2 at U20-11, U23-11, and U20-4. Is the signal toggling? Is the MBC signal present at U20-4. If the signal is present, replace U20. If the signal isn't present, continue to step 8. 8. Check U9 Is U9 receiving power? Look for +5V at U9-40. U9-20 is ground. Check character clock input. Use the schematics in Chapter 7 to check the circuitry between u20-8 and U9-16. Are there shorts? Is any portion of the circuitry open? If the signal is missing and you find no open circuit, replace U20. If the signal is missing and you find no shorts, replace U9. Check controller select activity at U9-2. If no shorts and no open lines, go to step 9. Check interrupt lines: U9-5 (toggles at 1.5 KHz) U9-35 (toggles every 16.6ms) Are they short or open? 3-8 Figure 3-1 Troubleshooting Flowchart, page 4 of 1 No Video/No Beep, Continued 8. Chec k U9 (continued) If U9 is being addressed by U1, but U9 is not toggling, replace it. If interrupts are active, but not toggling, go to step 9. If interrupts are active and toggling, check the soft font data path, U19- CO to C7. Check MBC output: If there is no output, check U1, all read/write and data connections. If no output and selection functions occur, replace U9. 9. Check U1 Check HSYNC output U9-19. 26.58 KHz. Look for Chec k po wer to U1. ground. Ul-20 is U1-40, Check the processor clock: Ul-18, U1-19, and connectej circuitry including X4, C10, and C11. Check signal PSEN, U1-29 to U6-22. If there is no activity present, check U6, U7, U4, U1, their interconnections and all address and data busses connected to U1. Check signal ALE, Ul-30. Look for a signal at 1/12th the clock rate. If this signal is not present, check the reset line Ul-9, and the processor clock, Ul-18 and U1-19. Check U1-1. In standard operation in 80-column mode, this pin is low. If PSEN and ALE are functioning and this line is high, check all address and data busses. Is U6 plugged into its socket backwards? 3-9 Figure 3-1 Troubleshooting Flowchart, page 5 of 7 Dim Video 1. Check user brightness control Adjust the brightness slideswitch. 2. Adjust brightness Perform the brightness alignment found in "Brightness", Chapter 4. 3. Check brightness circuitry Check VR202, and 0205. VR203, VR204, D203, Pin 1 of the CRT (att"lched to the green wire) should vary between +12 and -100VOC when the brightness control slideswitch moves from its highest to its lowest points. Check all connected circuitry. Check video output pins on U20. Other Video Problems 1• A vertical line of video Check the vertical yoke and the vertical deflection circuit. 2. A horizontal line of video Chec k the yoke. 3. Raster, no video Check the video amplifier, U20, all open video lines, and the CRT socket. Fails Self-Test or Diagnostic Test 1• Check setup Make sure you correctly selected the diagnostic test. 2. Check loopback connectors They may be missing, on the wrong ports or faul ty. Check Append ix C to make sure all connections are correct. If a letter has appeared on the screen, before running the self-test, or you have run self-test, and one or more letters or numbers appear on the screen, check the error codes below and their corresponding recommended actions. All components referred to are found on the logic PCB unless otherwise stated. 3-10 Figure 3-1 Troubleshooting Flowchart, page 6 of 7 Fails Self-Test or Diagnostic Test, Continued Error Code Indication Recommended Actions a Problems accessing character RAM U7 a. Check U 1 , U5. b. Chec k U7. Problems rtccessing attribute RAM u8 a. Check U 1 , U5. b. Check U8. Problems accessing U2 a. Check U1-2, -3. b. Check power at U2-8. Look for +5V. U2-4 is ground. c. Check clock and data signals at U2-5 and U2-6. d. Replace U2. MODEM port loop-back error a. E AUX port loop-back error, DSR-DTR a. Check U1-4, U1-5. b. Check U27 and U28. K Nonvolatile RAM error ~. Turn the unit off. b. While pressing the SETUP key, turn the power on. Continue to press the SETUP key until the screen flashes. p External EPROM error Replace U6 with appropriate part. p Internal ROM error Replace U1. W Send error, MODEM to AUX Check U28, U26, X3l, x MODEM port data error Check U25, y AUX port data error Check U28, U27. z Send error, MODEM Cher:;k U25, 9 A, C Check signals DTR and DCD for signal levels at U3 (UART). b. Check receivers and transmitters U25 and u26. c. Check X3. AUX to 3- 11 U26, U27, and U3. U3. X3, and U3. Figure 3-1 Troubleshooting Flowchart, page 1 of 1 Miscellaneous Symptoms Ke yboard no t operating Communication problems a. Check keyboard cable for continuity. b. Perform the keyboard test (see "Checking the Keyboard" in this chapter) . c. Check connector J1 on the keyboard PCB for shorts or breaks, repair if necessary. d. Check U1 (keyboard scanner) on the keyboard PCB for correct operation. Replace if necessary. e. Check U23 on the terminal PCB. a. Check setup information against the host's requirements. Change to match. b. See in form a tion reI a ted to communciation error codes on page 3 - 11 . Characters scrambled or degraded, dots missing Check U16, U19, U20. Characters don't appear on the screen Check U19 and U20. If the cursor and the status line appear, assume a communications problem. See the information related to communications error codes on page 3-11. ADDITIONAL TROUBLESHOOTING PROCEDURES This section contains a number of specialized procedures to help you repair the terminal. Some of them are referenced on the troubleshooting flowchart. Installation Checklist The checklist in Table 3-2 helps you to quickly determine if the terminal is installed correctly. If a user installs the terminal inc 0 r r e c t 1 Y, i t may not fu n c t ion pro per 1 y. 3-12 Table 3-2 o Terminal Installation Checklist Environment Room temperature is between +40 and +91 degrees Fahrenheit (5 and 33 degrees Celsius). Terminal isn't near a magnetic field. o Keyboard Keyboard cable is in the keyboard connector jack on the left side of the terminal. Keyboard cable is in the connector jack on the rear of the keyboard. o AC Power Cord Female end of the power cord is plugged into the AC power socket on the rear panel of the terminal. Male end of the power cord is plugged into wall socket. o Communication Interface Cable One end of the RS-232C interface cable is connected to the MODEM port on the terminal's rear panel. The other end of the interface cable is correctly connected to the computer. o Computer Interface (You'll need to check the computer's documentation to determine the following information.) Correct baud rate Correct stop bits Correct data bits Correct parity type Correct handshaking protocol 3-13 Checking for Continuity Sometimes you can fix the problem without opening the terminal. The problem could be a damaged cable or power cord. Sometimes, you may need to open the terminal to check the fuse or internal connections. Check this list, then r with an ohmmeter, check the continuity of the components listed below. Outside the terminal, check the o Power cord o Communication cable (supplied with the computer) Inside the terminal, check the o Fuse o AC power input receptacle (on the rear panel of the terminal) o Terminal PCB to the CRT/yoke wiring harness Hold the probes in place for five seconds, or until the ohmmeter settles, to ensure an accurate reading. If the part in question is open, replace it. Power Supply Check on the Terminal PCB You can quickly isolate problems if you check power supply voltages on the terminal PCB. Tools required: o No.2 Phillips screwdriver o Digital multimeter o Nonconductive video alignment tool To check the voltages, follow these steps: 1. Turn the terminal off. 2. Remove the terminal enclosure. 3. Attach one lead from the DMM to the chassis as ground. 4. Turn the terminal on. 3-14 5. With the other lead from the DMM, look for the following voltages at the specified points on the terminal PCB: Voltage +5V ~5% Point U1-40 (U1-20 is ground) +12V ~5% U27 - 14 ( U2 7 -7 is g ro un d ) -12V ~5% U27-1 (U27-7 is ground) 6. If one or more of these voltages are not in tolerance, adjust VR101. 7. If you adjust VR101, and the voltage or voltages are still not within tolerance, replace or troubleshoot the terminal PCB. Checking the Keyboard If you suspect the keyboard is the source of the problem, follow this procedure to verify it: 1. Turn the terminal off. 2. Disconnect the communication cable. 3. Connect pins 2 and 3 on the MODEM port. 4. Turn the terminal on. 5. The terminal should be in FDX (full-duplex) mode. (If it isn't, go into setup mode, select the FDX parameter, then leave setup mode.) 6. Type on the keys. Test all the keys in shifted and unshifted positions. If the keys don't respond, see section E of "Troubleshooting Flowchart." Isolating Circuits If you troubleshoot to the component level using the schematics in Chapter 7, you may want to isolate the logic, monitor, or power supply circuitry. Table 3-6 is a list of jumpers on the terminal PCB and the areas they isolate. For an exact location, see the terminal PCB component layout in Chapter 5. 3-15 Table 3-3 Terminal PCB Circuit Isolation Jumpers Jumper Areas Isolated J681 J682 Power supply from logic +5 volt supply J 75 9 J760 Video circuit Logic from monitor circuitry J532 J533 Video a Video 1 J665 J535 Vertical synchronization Logic from monitor circuitry J583 J749 Horizontal synchronization Logic from monitor circuitry For Service Manuals MAURITRON SERVICES 8 Cherry Tree Road, Chlnnor Oxfordshlre, OX9 4Qy' Tel (01644) 351694 Fax (01644) 352554 emall:- maurltron@dlal_plpex_com 3-16 4 ADJUSTMENTS AND ALIGNMENTS Before you Start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1 Sa fety Summ ary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2 Required Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2 Checking Display Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2 Aligning the Terminal Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5 Adjusting the Terminal Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10 Vertical Hold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Height . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Width . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Yoke Lock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Centering Rings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Display Magnets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Brightness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Foc us . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Linearity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10 4-11 4-11 4-11 4-11 4-13 4-14 4 -14 4-15 Test Patterns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-15 Pattern M . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-15 Pattern 0 . . . . . . . . . • . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-16 BEFORE YOU START This chapter describes 3.djustments and align!nents for the terminal. In particular, it discusses voltage adjustments, full monitor alignment, and individual adjustments. Before you align the monitor, check to see if the display meets the specific3.tion. If it doesn't, follow the set of instructions in the alignment section. You should complete a full terminal alignment whenever you replace the terminal printed circuit board (PCB) or the cathode ray tube (CRT)/yoke assembly. WARNING--The CRT/yoke assembly has high voltages. service personnel should adjust it. 4-1 Only qualified Safety Summary This terminal contains high voltage. Don't attempt to service the terminal without taking all the precautions you need for working with high volt3ge. o If you must open the terminal for any reason, first turn off the power and unplug the terminal. o Remove any jewelry, especially any on your hands, wrists, or neck. o Avoid wearing clothing that carries a static charge. o Use only insulated or nonconductive tools. o If you need to remember that the nec k. The radius of ten remove or replace the CRT/yoke assembly, it can implode if you drop it or break fl ying glass can in jure an yon e wi thin a feet. Required Tools Before testing the power supply voltages or making any adjustments to the terminal display, make sure you have the tools listed below: o Flat-bladed nonconductive alignment tool o Hex nonconductive alignment tool o No.2 Phillips screwdriver o Digital voltmeter (DVM) o Millimeter ruler or reticle (the reticle is optional--see Appendix D for instructions on how to use the reticle when you check the display.) o Diagnostic test connectors (see Chapter 5 to order them or Appendix C to make them) CHECKING THE DISPLAY SPECIFICATION Before you adjust the display on the monitor, measure the screen margins and study the display. Tools required: o Millimeter ruler or reticle (reticle is optional) o Diagnostic test connectors 4-2 ~ r !, Follow this procedure to determine whether or not the display is within specification. Notice that the procedure contains two columns, one to describe specific actions and one for comments and descriptions. ACTION COMMENTS 1. Turn off the terminal. Unplug it from its AC power source and disconnect any communications cables. 2. Attach the diagnostic test connectors to the MODEM and AUX ports on the rear panel of the logic pedestal. See Chapter 5 if you need to order these connectors or Appendix C for instructions to make them. 3. Plug in the terminal and turn it on. Let the terminal run for 30 minutes. Before you check the display to determine if the power supply or monitor assembly need adjustments or alignment, let the terminal run for 30 minutes. This assures you that the display is stable and will not drift or display other distortion after you measure it. 4. Hold the SHIFT key, the SETUP key. 5. Press the F2 function key. 6. Press the CURSOR DOWN key twice. Press the CURSOR RIGHT key once. 7. Press the SPACEBAR. 8. Press the FlO key. 9. Press CURSOR RIGHT once. 10. Press the FlO key again. then press Look for the TEST=OFF field in the third line of the setup menu. This toggles the TEST field ON. This saves the selection you've made and start the diagnostic self-test. You.should see a flashing t est p3 t t ern 0 f asterisks. 4-3 ACTION COMMENTS 11. Wait until the screen displays the Walking RAM Character Test, then hold down the SPACEBAR until the test pattern stops flashing. You will see the test pattern M. 12. C.3.ll test pattern 0 by pressing the CTRL and A keys simul taneously. You can toggle between patterns 0 and M with the CRTL A keystroke command. Both test patterns are described and illustrated in "Test Patterns" in this chapter. When toggling between test patterns 0 and M, you will find another pattern--the character/ attribute test pattern. It contains several rows of characters, each displayed with a different attribute'. Look at this pattern when you are troubleshooting. You should not depend on measurements from this test pattern during alignment. 13. If you don't have a reticle, measure the margins on the top, bottom, and both sides of test pattern 0 with a millimeter ruler. Each margin should measure 11 mm +2mm. If they don't, see "Aligning the Terminal Display." If you have a reticle, see Append ix D. 14. Look at the display. If there is barreling or pincushioning, if any of the display edges aren't str3.ight, or if there are size or centering problems, see "Aligning the Terminal Display." 15. Press CTRL A. You will see test pattern M on the screen. 4-4 ACTION COMMENTS 16. Look at the display. Check for brightness balance between the three blocks, making sure that the raster doesn't show when operator brightness slideswitch is pushed completely to the right. 17. Look at the display again. Are the letters on the top of this pattern the same size as the letters at the bottom? Are they the same size throughout? Are there any focus problems on the screen? If there are problems, skip steps 15 and 16. Go to "Aligning the Terminal Display." 18. If the display is within specification and looks regular, press the SETUP key. 19. Turn the terminal off. Remove the connectors and reattach the communications cables. ALIGNING THE TERMINAL DISPLAY The monitor has several alignments and adjustments. If the term inal display is out of tolerance in one or two areas, make adjustments to correct those problems with individual adjust~ents suggested in Table 4-1. If you change the CRT, the yoke, the CRT/yoke assembly, or the terminal PCB, you must perform a full alignment. Follow these procedures only if the display is out of tolerance and doesn't match the specification. Required tools: o Flat-bladed nonconductive alignment tool o Hex nonconductive alignment tool o No.2 Phillips screwdriver o Digital voltmeter (DVM) o DiagnostiC test connectors 4-5 WARNING--The CRT/yoke assembly has high voltages. Only qualified service personnel should perform these adjustments. Follow these steps to align the terminal display. Notice that the procedure has an action column that describes each step and a comments column that describes symptoms you should look for or other information that will help you with that step. Note--If you already have one of the test patterns on the screen, remove the terminal bucket and go to Step 10. COMMENTS ACTION 1. Turn off the terminal. Unplug it from its AC power source and disconnect any communications cables. 2. Remove the terminal bucket. See Chapter 2. 3. Attach test connectors to the MODEM and AUX ports In the rear panel of the logic pedestal. See Chapter 5 if you need to order these connectors or Appendix C for instructions to make them. 4. Plug in the terminal and turn it on. Let the terminal run for 30 minutes. Before you check the display to determine if the power supply or monitor assembly need adjustments or alignment, let the terminal run for 30 minutes. This assures you that the display is stable and will not drift or display other distortion after you measure it. 5. Hold the SHIFT key, then press the SETUP key. 6. Press the F2 function key. 7. Press the CURSOR DOWN key twice. Press the CURSOR RIGHT key once. 8. Press the SPACEBAR. 9. Press the F10 key. 10. Press the CURSOR RIGHT key once. Look for the TEST=OFF field in the third line of the setup menu. This toggles the TEST field ON. 4-6 ACTION COMMENTS 11. Press the F10 key again. This saves the selection you've made and starts the diagnostic self-test. You should see a flashing test pattern of asterisks. 12. Wait until the screen displays the scrolling ASCII test pattern, then hold down the SPACE BAR until the test pattern stops flashing. You will see test pa t tern M. 13. Call test pattern 0 by pressing the CTRL and A keys simultaneously. You can toggle between patterns 0 and M with the CRTL A keystroke command. Both test patterns are described and illustrated in "Test Pa tterns" in this chapter. When toggling between test patterns 0 and M, you will find another pattern--the character/ attribute test pqttern. It contains several rows of characters, each displayed wi th a different attribute. Look at this pattern when you are troubleshooting. You should not depend on measurements from this test pattern during alignment. 14. Use the DVM to check the +5V supply at R20 on the terminal PCB. The keyboard socket is ground. See 15. Adjust VR101 until the digital voltmeter reads +5V +2 percent. If you can't adjust the power supply into tolerance, see "Troubleshooting," Chapter 3. 4-7 Figure 4-1, "Power Supply Component Layout." Figure 4-1 Power Supply Component Layout ~ ~ ~ ~ ~ ~~ ~VR101 ~Q}J'\I U26 \ Q]J R20 II II \I \I \ rJD O [Q] \ O II r-I fl) rIJ R18 II ~II I~_ _--'~~ U
Source Exif Data:
File Type : PDF File Type Extension : pdf MIME Type : application/pdf PDF Version : 1.6 Linearized : No Create Date : 1998:03:24 13:15:32Z Creator : Acrobat 3.0 Import Plug-in Modify Date : 2016:07:04 10:31:18-07:00 XMP Toolkit : Adobe XMP Core 4.2.1-c041 52.342996, 2008/05/07-21:37:19 Creator Tool : Acrobat 3.0 Import Plug-in Metadata Date : 2016:07:04 10:31:18-07:00 Producer : Adobe Acrobat 9.0 Paper Capture Plug-in Format : application/pdf Document ID : uuid:f88245a3-d9af-8742-97e1-d3b2967511a2 Instance ID : uuid:199e790c-380b-e04a-b57b-f469d85f7a0c Page Layout : SinglePage Page Count : 136EXIF Metadata provided by EXIF.tools