Service Manual ViewSonic VG2021m-1 Model No. VS11234 20” Color TFT LCD Display (VG2021m-1_SM Rev. 1a Apr.
Copyright Copyright © 2006 by ViewSonic Corporation. All rights reserved. No part of this publication may be reproduced, transmitted, transcribed, stored in a retrieval system, or translated into any language or computer language, in any form or by any means, electronic, mechanical, magnetic, optical, chemical, manual or otherwise, without the prior written permission of ViewSonic Corporation.
TABLE OF CONTENTS 1. Precautions and Safety Notices 1 2. Specification 4 3. Front Panel Function Control Description 12 4. Circuit Description 17 5. Adjustment Procedure 18 6. Troubleshooting Flow Chart 51 7. Recommended Spare Parts List 59 8. Exploded Diagram and Exploded Parts List 63 9. Block Diagram 67 10. Schematic Diagrams 68 11.
1. Precautions and Safety Notices 1. Appropriate Operation (1) Turn off the product before cleaning. (2) Use only a dry soft cloth when cleaning the LCD panel surface. (3) Use a soft cloth soaked with mild detergent to clean the display housing. (4) Use only a high quality, safety approved AC/DC power cord. (5) Disconnect the power plug from the AC outlet if the product will not be used for a long period of time.
(9) In the event that a Module must be put back into the packing container slot after it was taken out of the container, do not press the center of the CCFL Reflector edge. Instead, press at the far ends of the CFL Reflector edge softly. Otherwise the TFT Module may be damaged. (10) At the insertion or removal of the Signal Interface Connector, be sure not to rotate or tilt the Interface Connector of the TFT Module.
Correct methods : Only touch the metal-frame of the panel or the front cover of the monitor. Do not touch the surface of the polarizer . Incorrect Methods : Surface of the panel is pressed by fingers & this may cause “ MURA “ Take out the monitor with cushion Take out the monitor by grasping the LCD panel. That may cause “ MURA“. Place the monitor on a clean & soft foam pad . Place the monitor on foreign objects .
2. Specification INTRODUCTION FEATURES Size Luminance (Typ) Contrast Ratio (Typ) Colors Response Time (Typ) Viewing Angle (H/V) VG2021M-1 20.1 “ 300 cd/㎡ 500:1 16.2 M colors TFTLCD PANEL 8 ms 150 / 130 @CR>=10 170/ 150 @CR>= 5 Recommend resolution 1400 X 1050 @60Hz Analog (75ohms, 0.7/1.
VIDEO INTERFACE Input Connector(refer the appendix A) Default Input Connector Video Cable Strain Relief Video Cable Connector DB-15 Pin out Video Signals Video Impedance Maximum PC Video Signal Maximum Mac Video Signal Sync Signals DDC 1/2B Sync Compatibility Video Compatibility Resolution Compatibility Exclusions Analog : D-sub 15 , Digital: DVI-D Defaults to the first detected input Equal to twice the weight of the monitor for five minutes Compliant DDC 2B 1. Video RGB (Analog): Separate 2.
ELECTRICAL REQUIREMENT Horizontal / Vertical Frequency Horizontal Frequency Vertical Refresh Rate Maximum Pixel Clock Sync Polarity 30 – 82 KHZ 56– 76 HZ. 156 MHz Independent of sync polarity. Timing Table Item Timing 1. 640 x 400 @ 70Hz, 31.5kHz 2. 640 x 480 @ 60Hz, 31.5kHz 3. 640 x 480 @ 67Hz, 35.0kHz 4. 640 x 480 @ 72Hz, 37.9kHz 5. 640 x 480 @ 75Hz, 37.5kHz 6. 720 x 400 @ 70Hz, 31.5kHz 7. 800 x 600 @ 56Hz, 35.1kHz 8. 800 x 600 @ 60Hz, 37.9kHz 9. 800 x 600 @ 75Hz, 46.9kHz 10. 800 x 600 @ 72Hz, 48.
Panel Characteristics: 1st Source Panel Type Active Size Pixel Arrangement Pixel Pitch GLASS TREATMENT # OF BACKLIGHTS BACKLIGHT LIFE Luminance – Condition: CT = 6500K, Contrast = Max, Brightness = Max Brightness Uniformity Contrast Ratio Color Depth Viewing Angle (Horizontal/ vertical) Response Time 10%-90% @ Ta=25°C Panel Defects A201P1 “TN Technology” 408.24 (H) x 306.18(V) RGB Vertical Stripe 0.
3. Front Panel Function Control Description Adjusting the Screen Image Use the buttons on the front control panel to display and adjust the OSD controls which display on the screen. Power light Blue = ON Orange = Power Saving Standby Power On/Off Audio Mute button turns the sound off Displays the Main Menu or exits the control screen and saves adjustments. Scrolls through menu options and adjusts the displayed control. Also a shortcut to display the Contrast adjustment control screen.
Do the following to adjust the screen image: 1. To display the Main Menu, press button [1]. NOTE: All On View menus and adjustment screens disappear automatically after about 15 seconds. This is adjustable through the OSD timeout setting in the setup menu. 2. To select a control you want to adjust, press p or qto scroll up or down the Main Menu. 3. After the control is selected, press button [2]. A control screen like the one shown below appears.
Main Menu Controls Adjust the menu items shown below by using the up p and down q buttons. Control Explanation Auto Image Adjust sizes and centers the screen image automatically. Contrast adjusts the difference between the image background (black level) and the foreground (white level). Brightness adjusts background black level of the screen image. Audio Adjust Volume increases the volume, decreases the volume, and mutes the audio. Mute temporarily silences audio output.
Control Explanation Information displays the timing mode (video signal input) coming from the graphics card in the computer, the LCD model number, the serial number, and the ViewSonic® website URL. See your graphics card’s user guide for instructions on changing the resolution and refresh rate (vertical frequency). NOTE: VESA 1400 x 1050 @ 60Hz (recommended) means that the resolution is 1400 x 1050 and the refresh rate is 60 Hertz. Manual Image Adjust Sub-menu H.
Language Select allows the user to choose the language used in the menus and control screens. Resolution Notice allows the user to enable or disable this notice. If you enable the Resolution Notice shown above and your computer is set at a resolution other than 1400 x 1050, the following screen appears. OSD Position allows the user to move the OSD menus and control screens. OSD Timeout sets the length of time the OSD screen is displayed.
4. Circuit Description The TSUM57AK is total solution graphics processing IC for LCD monitors with panel resolutions up to SXGA. It is configured with a high-speed integrated triple-ADC/PLL, an integrated DVI receiver, a high quality display processing engine, and an integrated output display interface that can support RSDS panel interface format.
5. Adjustment Procedure A. Function Test and Alignment Procedure 1. All Modes Reset You should do “All Model Reset” (Refer to Chap 3. Hot Keys for Function Controls) first. This action will allow you to erase all end-user’s settings and restore the factory defaults. 2. Auto Image Adjust The Auto Adjust is aimed to offer a best screen quality by built-in ASIC. For optimum screen quality, the user has to adjust each function manually. A.Turn the computer and LCD monitor on. B.
8. 50 Gray Test Signal: 1400*1050@60Hz Test Pattern: Full Screen 50% White (Gray) Inspection Item: Bright Dot, Particle, Line Defect & Mura 9. White Box Test Signal: 1400*1050@60Hz Test Pattern: Window standard pattern Inspection Item: Particle, Line Defect, Power, Image Remain & Mura 10. Black Box Test Signal: 1400*1050@60Hz Test Pattern: Window standard pattern Inspection Item: Bright Dot, Line Defect & Power 11.
14. Gray_Scale_0-100_V64 Test Signal: 1400*1050@60Hz Test Pattern: Vertical 64 (256) Gray Scale (Right → Left，From 0 to 100% White) Inspection Item: Line Defect & Function Defect 15.
Figure 5 Figure 6 Figure 7 Figure 8 ViewSonic Corporation Confidential - Do Not Copy 17 VG2021m-1
BIOS update procedure 1. To setup ISP environment Hardware: PC or Notebook , Parallel(Printer) cable , ISP tool( Fig 1) Software: ISP driver . If the O.S. was Win2000 or Win XP please have to install PORT95NT.
2. Install ISP 2.1 User could download ISP driver and PORT95NT install file from Myson Century website (http://www.myson.com.tw ) 2.2 After extracting the zip file, the total files list as Fig 2.2, and double click the file of setup.exe to install. Fig 2.2 2.3 Press “Next” button to continue., see Fig 2.3 Fig 2.
2.4 Keep default setting or press “Change” button for selecting the path that you want , and then press“Next”button to continue, see Fig 2.4. Fig 2.4 2.5 Press “Install” button to continue, see Fig 2.5 Fig 2.
2.6 The Installer Information shows package warning, press “Ignore” button to continue, see Fig 2.6. Fig 2.6 2.7 Installation has finished, press “Finish” button, see Fig 2.7. Fig 2.
3. ISP security code 3.1 After installation, we could find the shortcut in the setting path or the program bar (default setting), see Fig 3.1. Fig 3.1 2.2 Security file is a key to use ISP function, press “確定” button, see Fig 3.2. Fig 3.
3.3 The warning is used to remind user of that different CPU rate may cause ISP function fail(it is limited by IIC protocol), press “確定” button, see Fig 3.3. Fig 3.3 2.4 Press“Create Security File” button to key in security code. Adjusting bar to decrease speed of IIC bus, see Fig 3.4. Fig 3.
3.5 At least 2 Command No of security code, see Fig 3.5, and different security code between hardware ISP and software ISP. The security code of software ISP is set by user while coding, but the security code of hardware ISP is set by Myson Century. Fig 3.
3.6 Fig 3.6 shows the setting for security code of hardware ISP, it needs 4 Command No, and key in command sequentially for 94, 94, AC, CA, 53. Fig 3.
3.7 Fig 3.7 shows the setting for security code of software ISP, it needs 2 Command No, and key in command sequentially for 7C, 4C, 77. The Command No and command must be set by user while coding. About the detail of setting, please refer to Section 6 Boot code of ISP. Fig 3.
4. Use ISP to program MCU 4.1 elect MTV type first, load the binary or Intel hex file that you want to program into the MCU, and select “Auto” item, then press “RUN” button, see Fig 4.1. 4.2 f user changes the MTV type, it must load file again, or the buffer of load file will be cleared. 4.3 RC (cyclic redundancy check): the host can check CRC register’s result instead of reading every byte in flash. The message of Check MCU CRC OK means that the Host verify ok for the progress of program. Fig 4.
5 Use ISP to read MCU content 5.1 nly software ISP could read the MCU content, it is according to program the boot code while coding. The limitation is used for the security of customer’s code. Select “Read Target” item, and press“RUN” button, the MCU content will show as Fig 5.1. Fig 5.
5.2 If user uses hardware ISP to read MCU content, it shows as Fig 5.2. Fig 5.
6 Re-entry the ISP Mode When you could not select or click ‘Reset MCU’ button and enter ISP mode again, you refer the message as below: Note: (1)Disable the ‘Enter ISP Mode’ option to avoid the error message display. (2)If you using the MTV312M64 or before MCU serials, the MCU will always in ‘ISP Mode’even programming fail or erase MCU that instead of select or press ‘Reset MCU’.
7. Boot code of ISP 7.1 Hardware ISP (1) Without boot code (2) Fixed security code: 94, 94, AC, CA, 53 (3) Attention to the pin of HSCL (1) and HSDA (1) should keep in enable (4) MTV412M, MTV512M, CS8954 support hardware ISP 7.2 Software ISP (1) With boot code (2) User define the security code (3) Attention to the pin of HSCL (1) and HSDA (1) should keep in enable (4) Only software ISP could read the MCU content (5) MTV212M, MTV312M, MTV230M, MTV412M, MTV512M, CS8954 support software ISP 7.
7.4 The followings show the relationship between the code and the security code.
8. ISP Adaptor Schematic 9.
Packing For Shipping And Disassembly Procedure Packing For Shipping 1. Packing Procedure 1.1 Paste protection film to protect the monitor. (Figure 1) 1.2 Put the monitor in the PE bag and seal the bag with tape. (Figure 2) Figure 1 Figure 2 1.3 Put the cushions on the monitor. (Figure 3) 1.4 Place the monitor into the carton and then put all the accessories into the carton. As last, close the carton and seal it with tape.
D. Monitor Assembly and Disassembly 1. Separate Stand Assy 1.1 Remove Stand Cover Step 1 : Remove the Seat Assy Step 2 : Remove the Stand Cover. Step 3 : Press the mark A of Rear Cover mark A Step4 : Remove the Stand Assy Step 5 : Completed.
2. Separate Rear Cover (Rear Case Assy) Separate Bezel hooks to take Bezel and Rear Cover apart. Step 1 : Loose and remove 4 screws. Step 2 : Separate Bezel hooks to take Bezel and Rear Cover apart. Step 3 : Remove Rear Cover. Step 4 : Completed.
3. Remove Power Board and AD Board 3.1 Remove Metal Cover Step 1 : Remove FFC from OSD Board. Step 2 : Lift up LCD module and remove bezel. Step 3 : Remove 2 pieces of Backlight wires. Step 4 : Remove 2 pieces of Backlight wires.
Step 5 : Loose and remove 4 screws. Step 6 : Remove the Support Plate. Step 7 : Loose and remove 2 screws. Step 8 : Loose and remove 2 screws.
Step 9 : Loose and remove 2 screws. Step 10 : Remove the PCBA Cover 3.2 Remove Power Board and AD Board Step 1 : Loose and remove 4 screws.
Step 3 : Remove the FFC. Step 4 : Remove 2 pieces of FFCs. Step 5 : Loose and remove 4 screws. Step 6 : Remove AD PCBA. Step7 : Completed.
4. Change New AD Board and Power Board Step 1 : Place new AD Board. And fasten 4 fixed screws. Step 2 : Fasten 4 fixed screws. Step 3 : Insert 2 pieces of FFCs . Step 4 : Insert FFC. Step 5 : Insert new Lips Board.
Step 6 : Fasten 4 fixed screws. Step 7 :Completed. 5. Remove OSD Board Step 1 : Remove the FFC Step 2 : Separate both Audio Cables and OSD board. Step 3 : Loose and remove 2 screws.
Step 4 : Remove the FFC and OSD board. Step 5: Completed. 6.Change New OSD Board Step 1 : Place new OSD Board and insert FFC. Step 2 : Fasten 2 screws. Step 3 : Join new OSD board. Step 4 : Insert Audio cables and FFC.
7. Add Cover to AD PCB Heatsink Step 1 : Join the PCB Cover. Step 2 : Fasten 2 fixed screws. Step 3 : Fasten 2 fixed screws. Step 4 : Fasten 2 fixed screws. Step 5 : Join the Support Plate.
Step 6 : Fasten 4 fixed screws Step 7 : Insert 2 pieces of Backlight wires. Step 8 : Insert 2 pieces of Backlight wires. Step 9 : Join LCD module and remove bezel. Step 10 : Insert FFC. Step 11 : Completed.
8. Rear Assy & Stand Assembly Step 1 : Place Rear Cover. Step 2 : Fasten 4 fixed screws. Step 3 : Place the Stand Assy. Step 4 : Join the Stand Cover. Step 5 : Join the Seat Assy Step 6 : Completed.
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Defect Mode Failure Analysis Repair Testing ※ “ Panel Change” Should be Performed to Level 3 Repair stage A Display Noise Power on AD/B Change Check PCBA Display Power/B Change Abnormal Inverter/B Change Flicker CNT/B Change Beat Display Flicker Check Panel Panel Change Beat Display Shut Down Abnormal AD/B Change Display Wave Check PCBA Power/B Change CNT/B Change No Backlight Check Panel Panel Change Check Adapter Adapter Change NG Next Step B TEST Completed ViewSonic Corporation
Failure Analysis Repair Testing ※ “ Panel Change” Should be Performed to Level 3 Repair stage B Display White Out Check PCBA AD/B Change Power/B Change Booting Delay Check PCBA Inverter/B Change Brightness OSD/B Change Even Abnormal Check PCBA Inverter/B Change Beat Display No Backlight Power/B Change Check Panel Check Adapter Panel Change Adapter Change No signal AD/B Change R.G.
Defect Mode Failure Analysis Repair Testing ※ “ Panel Change” Should be Performed to Level 3 Repair stage C Horizontal Line Defect Vertical Weak Line Check PCBA AD/B Change Check Panel Panel Change Check PCB Horizontal Weak Line Vertical Band Defect Horizontal Band Defect Power Saving Display Abnormal AD/B Change Check PCBA Check PCB AD/B Change Peculiar Smell Power/B Change Check PCBA Check PCB Inverter/B Change NG Next Step TEST Complete ViewSonic Corporation Confidential - Do Not Co
Defect Mode Failure Analysis Repair Testing ※ “ Panel Change” Should be Performed to Level 3 Repair stage AD/B Change Power/B Change Power ON/OFF No Power Check PCBA Abnormal Turn Off Check PCBA CNT/B Change Inverter/B OSD/B Change Abnormal Check Wire OSD Cable Check Wire AC Power Change DC Power CNT Cable Change Check Adapter Adapter Change AD/B Change LED Display Abnormal LED Off Power/B Change Check PCBA Inverter/B LED Dark OSD/B Change LED Abnormal OSD Cable LED Loss Check Wire DC
Defect Mode Failure Analysis Repair Testing ※ “ Panel Change” Should be Performed to Level 3 Repair stage Abnormal BIOS &OSD OSD Key AD/B Change Unavailable CNT/B Change OSD Can’t Input Power/B Change Check PCB Inverter/B OSD Can’t Read OSD/B Change OSD No D-sub cable Display OSD cable Check Wire OSD Jiggle VGA cable DVI cable OSD Display Abnormal Abnormal Check BIOS BIOS Update AD/B Change Voice Loss Loudspeaker CNT/B Change Abnormal Loud Power/B Change Check PCBA Inverter/B Chang
Defect Mode Failure Analysis Repair Testing ※ “ Panel Change” Should be Performed to Level 3 Repair stage Other Abnormal Display Display Shut Check PCBA Down AD/B Change Power/B Change CNT/B Change Check Panel Display Flicker Panel Change Check PCBA ((tapping ) CNT/B Change Check Panel DVI Signal AD/B Change Panel Change Check PCB AD/B Change Check PCB Display Abnormal Check EDID Code Check PCB Check PCBA TV Function Display Abnormal Check Wire EDID Update TV /B Change AV Cable Cha
Trouble Shooting Analysis Check the information in this section to see if the problems can be solved before requesting repair. Note：The consumers are only allowed to solve the problems described as below. Any unauthorized product modification, or failure to follow instructions supplied with the product will end the warranty immediately. l No image u u l No Signal Input u l Use OSD Color Menu to adjust color setting. Dark area distorted u l Use OSD Color Menu to adjust color setting.
7. Recommended Spare Parts List RECOMMENDED SPARE PARTS LIST (VG2021m-1) ViewSonic Model Number: VS11234 Rev: 1a Serial No. Prefix: Q6U Item 1 Accessories: 2 3 Board Assembly: 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 Cabinets: Cables: Documentation: Hardware: Packing Material: Description ECR/ECN Power Code,UL,SVT#18/3C,75°C,LP-30B+LS-13, L=1830+/-50mm,Black Adapter - Lips With Audio,DAC-12M033 AF,00 A,12 V/0.
BOM LIST (VG2021m-1) ViewSonic Model Number: VS11234 Rev: 1a Serial No. Prefix: Q6U Item ViewSonic P/N Ref.
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EXPLODED PARTS LIST (VG2021m-1) ViewSonic Model Number: VS11234 Rev: 1a Serial No. Prefix: Q6U Item 1 2 3 4 5 6 7 8 9 10 11 12 13 14 ViewSonic P/N C-00005683 N/A C-00005671 C-00005672 C-00005674 C-00005684 N/A CB-00005676 CB-00005675 B-00005703 B-00005704 HW-00000557 HW-00005679 HW-00000555 Ref.
PACKING PART LIST ( VG2021m-1 ) ViewSonic Model Number: VS11234 Rev: 1a Item 1 2 3 4 5 6 7 8 9 10 11 12 ViewSonic Corporation Confidential - Do Not Copy 59 VG2021m-1 ViewSonic P/N N/A P-00002374 P-00005681 P-00005682 N/A C-00005674 N/A N/A CB-00005678 CB-00004287 CB-00002083 N/A Ref.
9. Block Diagram Speaker OSD Key Pad / Audio Out 3.
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VCC33 VDPP L10 VDDC 70 71 72 73 R116 0603/10K/5% C94 0603/22p/50V/N Y1 14.
0603/1K/5%/RoHS V33C R12 V33C V33C R9 0603/10K/5%/RoHS 3 R13 Q1 2N7002/RoHS 0603/1u/10V/Y/open 2 1 1 VIN_12V 1 0603/4.7K/5%/RoHS R14 V5A1 TP VIN_12V1 TP LP2 FBMJ2125HS420/PbF LP3 FBMJ2125HS420/PbF LP4 FBMJ2125HS420/PbF INV_ON/OFF1 INV_ADJ 0603/4.7K/5%/RoHS 3 C7 V5A C8 0603/0.1u/25V/open Q2 2N7002/RoHS R10 1 2 GND INV_ON/OFF 1 TP INV_ADJ INV_ON/OFF 1 GND [GND_INV] INV_ADJ1 0603/4.
V18C D7 BAV70W/open V18C Q8 3 V33C1 B GND 4 E C 2 1 1 C160 0805/4.7u/16V/Y H2907AS R203 0603/2K/1% 2 TP 1 B240A-F C42 C44 C43 0603/100n/25V/7/RoHS 1206/22u/16V/Y/RoHS Vref LM1117MPX-3.
水波紋: 靠IC R35 DDCA_DAT 0603/0R/5%/OPEN 11 1 6 2 7 3 8 4 9 5 10 12 13 14 15 R78 R30 R29 0603/75R/1% 0603/75R/1% 0603/75R/1% R21 0603/56R/1% C9 0603/47n/16V/7/RoHS R34 0603/56R/1% C10 0603/47n/16V/7/RoHS R23 0603/56R/1% C11 0603/47n/16V/7/RoHS R24 0603/470R/1% C15 0603/1n/16V/7 RIN GIN BIN SOG CN7 89263-6762 R25 D1 1 R144 0603/0R/5%/OPEN D2 D24 1 BAV99W/RoHS 1 D25 BAV99W/RoHS C157 0603/100n/25V/X/RoHS DDCA_CLK L20 2 HSI GND 2 C159 0603/100n/25V/X/RoHS 0603/0R/5%/RoHS R57
V5A_ESD CON1 DDCD_CLK DDCD_DAT R37 0603/0R/5%/RoHS R38 0603/0R/5%/RoHS 2 L6 1 DVI_5V 3 0603/100n/25V/7 0603/100n/25V/7 0603/100n/25V/7 0603/100n/25V/7 D17 UDZSF-5.
5 6 7 8 5 6 7 8 4 3 2 1 RP46 0603*4/10K/5%/RoHS 4 3 2 1 V33C RP47 0603*4/10K/5%/RoHS Bead Array LP8,LP9,LP11=>modified RoHs MENU LEFT RIGHT TURBO AUTO LED_O LP6 1 2 3 4 LP7 1 2 3 4 LED_G POWER CN3 8 BK32164M121 7 6 5 8 BK32164M121 7 6 5 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 L1 AUDIOR- 1 2 MPZ1608S221/RoHS AUDIOR+ CP7 CP8 0603*4/100n/25V/RoHS 0603*4/100n/25V/RoHS V33C 5 6 7 8 R36 R62 0603/10K/5%/RoHS 0603/1K/5%/RoHS/OPEN R7 5 6 7 8 V33C 4 3 2 1 4 3 2 1 L2 V33C AUDIOL- 1 2 MPZ16
VCC1 VCC 1 STV 1 BB2P BB2N BB1P BB1N BB0P BB0N STV1 BG2P BG2N BG1P BG1N BG0P BG0N CPV1 CPV 1 BCKP BCKN BR2P BR2N BR1P BR1N BR0P BR0N OE1 OE 1 STB 1 STB1 BSTH V5A POL1 POL GVOFF VCM_PWM DCDC_ON/OFF PANEL_ON/OFF GND V5A 1 BSTH GVOFF VCM_PWM DCDC_ON/OFF PANEL_ON/OFF 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 CN1 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 CN2 IL-FHR-F36S-HF/Ro
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* Reader’s Response* Dear Readers: Thank you in advance for your feedback on our Service Manual, which allows continuous improvement of our products. We would appreciate your completion of the Assessment Matrix below, for return to ViewSonic Corporation. Assessment A. What do you think about the content of this Service Manual? Unit Excellent Good Fair Bad 1. Precautions and Safety Notices 2. Specification 3. Front Panel Function Control Description 4. Circuit Description 5. Adjustment Procedure 6.
