Apple Multiple Scan 720 Display Service Manual

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Apple Multiple Scan 720 Display

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Service Source

Hot Issues

Apple Multiple Scan 720 Display
Hot Issues Introduction - 1

Introduction

This chapter is designed to highlight unique or high­priority product issues that you should be aware of before servicing this display.
This chapter alerts you to important issues and provides links to other areas in the manual where more complete information can be found. This chapter is not intended to replace other parts of this manual; it merely provides a pointer to pertinent information in those chapters.
Hot Issues Jittery or Blurry Video with Power Macintosh 5500/6500 - 2
Jittery or Blurry Video with Power Macintosh 5500/6500
If the display exhibits jittery or blurry video when connected to a Power Macintosh 5500 or 6500, suspect the computer, not the monitor.
Video jitter affects monitors connected to computers having a 225 or 250 MHz logic board. Jitter is evident where the pixels shimmer or jump at the edges of the screen, windows, or dialog boxes.
Blurry video is seen as a fuzzy image over the entire screen on monitors set to resolutions of 832x624 and higher.
Hot Issues Jittery or Blurry Video with Power Macintosh 5500/6500 - 3

Identifying Suspect Units

Video jitter or blurry video can be caused by Power Macintosh computers within the following serial number ranges.
Video Jitter
• PM 5500 from TY705xxxxx to TY715xxxxx
• PM 6500 from XB708xxxxx to XB718xxxxx
Blurry Video
• PM 6500 from XB708xxxxx to XB723xxxxx
The system software on Power Macintosh 6500 computers allows selecting monitor resolutions above 1152x870. But these higher resolutions are not supported and cause poor video output, such as misaligned or skewed video, low brightness, blurriness, and so on. Monitors connected to
Hot Issues Jittery or Blurry Video with Power Macintosh 5500/6500 - 4
Power Macintosh 6500 computers should not be set to resolutions higher than 1152x870.
Check the control strip to make sure the resolution is set to 1152x870 or lower. For a chart of supported monitor resolutions for the Power Macintosh 6500, see the Specifications chapter in the Performa/Power Macintosh 6400 and 6500 Series manual on Service Source.
Although these symptoms have never been reported for a Power Macintosh 5500, the 225 MHz logic board used in the Power Macintosh 6500 is also used in the 5500. Refer to the Troubleshooting chapter in Service Source for both Power Macintosh manuals.
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Basics

Apple Multiple Scan 720 Display
Basics Overview - 1

Overview

The Apple Multiple Scan 720 Display is a low-cost 17-inch (16.0-inch viewable image size) monitor. It offers screen resolutions ranging from 640x480 to 1280x1024.
The Apple Multiple Scan 720 Display complies with TCO 95 as certified by the Swedish confederation of Professional Employees to meet global safety tests and energy-saving features.
Basics Overview - 2

Features

Features of the Apple Multiple Scan 720 Display include
• 17-inch (16.0-inch VIS) CRT
• 0.28 mm dot pitch
• Multiple resolutions
• User controls for brightness, contrast, and On-Screen Display geometry controls
• Mac OS-based and Windows-based compatibility
• Energy Star compliance
• TCO 95 compliance
Basics Overview - 3
The front panel of the display includes the following controls:
• Power button
• Brightness
• Contrast
• On-Screen Display (OSD) select/adjust control
• On-Screen Display (OSD) enter button
Refer to the Adjustments chapter for a list of picture-quality adjustments that can be made using the On-Screen Display.
Basics Overview - 4

Repair and Replacement Tips

The monitor stand does not need to be removed before the rear housing is removed, however the monitor stand is easiest to remove when the monitor is completely assembled.
When the rear housing is removed, special care must be taken to avoid damaging the monitor assembly. The rear housing helps support the weight of the main deflection board and CRT/video board.
The CRT/video board and the main deflection board cannot be separated without risk of damaging the CRT socket. Therefore, the CRT/video board and main deflection board are offered as one module.
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Specifications
Apple Multiple Scan 720 Display
Specifications Characteristics - 1

Characteristics

Picture Tube

Screen Resolution

17-in. diagonal flat square CRT (16.0-in. diagonal viewable
image)
Multiple scan, antistatic, antiglare surface treatment
0.28-mm dot pitch
640x480 at 60 Hz in VGA mode 640x480 at 66.7 Hz in Macintosh mode 640x480 at 85 Hz in VESA mode 800x600 at 60 Hz in VESA mode 800x600 at 72 Hz in VESA mode 800x600 at 85 Hz in VESA mode 832x624 at 75 Hz in Macintosh mode 1024x768 at 60 Hz in VESA mode 1024x768 at 70 Hz in VESA mode
Specifications Characteristics - 2
1024x768 at 75 Hz in VESA mode 1024x768 at 85 Hz in VESA mode 1152x870 at 75 Hz in Macintosh mode 1280x1024 at 60 Hz in VESA mode

Scan Rates

Cable Connector

Input Signals

Vertical refresh rate: 48–160 Hz Horizontal scan rate: 30–70 kHz
15-pin miniature D-type
Red, green, and blue signals; separate sync
Specifications Characteristics - 3

System Requirements

Power Macintosh, Macintosh Performa, and Macintosh Quadra
computers with 68040 or later microprocessors running Macintosh Operating System software version 7.5 or later
Windows and MS-DOS software-based computers using VGA
(adapter required)
Specifications Characteristics - 4

Monitor Timings

640x480 Resolution @ 60 Hz
Horizontal Timing Horizontal Timing 1/H: 31.5 kHz 1/H: 35 kHz Back Porch: 48 dots Back Porch: 96 dots H SYNC: 96 dots negative H SYNC: 64 dots negative Front Porch: 16 dots Front Porch: 64 dots 1 H: 31.75 µs 1 H: 28.6 µs 1/dot: 25.175 MHz 1/dot: 30.24 MHz
Vertical Timing Vertical Timing 1 V: 16.7 ms 1 V: 15.0 ms Back Porch: 33 H Back Porch: 39 H V SYNC: 2 H negative V SYNC: 3 H negative Front Porch: 10 H Front Porch: 3 H
640x480 Resolution @ 66.7 Hz
Specifications Characteristics - 5
Monitor Timings
640x480 Resolution @ 85 Hz
Horizontal Timing Horizontal Timing 1/H: 43.26 kHz 1/H: 37.87 kHz Back Porch: 80 dots Back Porch: 88 dots H SYNC: 56 dots negative H SYNC: 128 dots positive Front Porch: 56 dots Front Porch: 40 dots 1 H: 23.11 µs 1 H: 26.40 µs 1/dot: 36.000 MHz 1/dot: 40.000 MHz
Vertical Timing Vertical Timing 1 V: 11.8 ms 1 V: 16.6 ms Back Porch: 25 H Back Porch: 23 H V SYNC: 3 H negative V SYNC: 4 H positive Front Porch: 1 H Front Porch: 1 H 1/V: 85 Hz 1/V: 60 Hz
800x600 Resolution @ 60 Hz
Specifications Characteristics - 6
Monitor Timings
800x600 Resolution @ 72 Hz
Horizontal Timing Horizontal Timing 1/H: 48.0 kHz 1/H: 53.67 kHz Back Porch: 64 dots Back Porch: 152 dots H SYNC: 120 dots positive H SYNC: 64 dots positive Front Porch: 56 dots Front Porch: 32 dots 1 H: 20.80 µs 1 H: 18.6 µs 1/dot: 50.000 MHz 1/dot: 56.250 MHz
Vertical Timing Vertical Timing 1 V: 13.9 ms 1 V: 11.8 ms Back Porch: 23 H Back Porch: 27 H V SYNC: 6 H positive V SYNC: 3 H positive Front Porch: 37 H Front Porch: 1 H
800x600 Resolution @ 85 Hz
Specifications Characteristics - 7
Monitor Timings
832x624 Resolution @ 75 Hz
Horizontal Timing Horizontal Timing 1/H: 49.72 kHz 1/H: 48.36 kHz Back Porch: 224 dots Back Porch: 160 dots H SYNC: 64 dots negative H SYNC: 136 dots negative Front Porch: 32 dots Front Porch: 24 dots 1 H: 20.1 µs 1 H: 20.67 µs 1/dot: 57.283 MHz 1/dot: 65.0 MHz
Vertical Timing Vertical Timing 1 V: 13.4 ms 1 V: 16.7 ms Back Porch: 39 H Back Porch: 29 H V SYNC: 3 H negative V SYNC: 6 H negative Front Porch: 1 H Front Porch: 3 H
1024x768 Resolution @ 60 Hz
Specifications Characteristics - 8
Monitor Timings
1024x768 Resolution @ 70 Hz
Horizontal Timing Horizontal Timing 1/H: 56.47 kHz 1/H: 60.023 kHz Back Porch: 144 dots Back Porch: 176 dots H SYNC: 136 dots negative H SYNC: 96 dots positive Front Porch: 24 dots Front Porch: 16 dots 1 H: 17.70 µs 1 H: 16.6 µs 1/dot: 75.000 MHz 1/dot: 78.75 MHz
Vertical Timing Vertical Timing 1 V: 14.3 ms 1 V: 13.3 ms Back Porch: 29 H Back Porch: 28 H V SYNC: 6 H negative V SYNC: 3 H positive Front Porch: 3 H Front Porch: 1 H
1024x768 Resolution @ 75 Hz
Specifications Characteristics - 9
Monitor Timings
1024x768 Resolution @ 85 Hz
Horizontal Timing Horizontal Timing 1/H: 68.677 kHz 1/H: 68.681 kHz Back Porch: 208 dots Back Porch: 144 dots H SYNC: 96 dots positive H SYNC: 128 dots negative Front Porch: 48 dots Front Porch: 32 dots 1 H: 14.561 µs 1 H: 14.56 µs 1/dot: 94.500 MHz 1/dot: 100.00 MHz
Vertical Timing Vertical Timing 1 V: 11.8 ms 1 V: 13.3 ms Back Porch: 36 H Back Porch: 39 H V SYNC: 3 H positive V SYNC: 3 H negative Front Porch: 1 H Front Porch: 3 H
1152x870 Resolution @ 75 Hz
Specifications Characteristics - 10
Monitor Timings
1280x1024 Resolution @ 60 Hz
Horizontal Timing 1/H: 63.8 kHz Back Porch: 248 dots H SYNC: 112 dots positive Front Porch: 48 dots 1 H: 15.6 µs 1/dot: 108 MHz
Vertical Timing 1 V: 16.7 ms Back Porch: 38 H V SYNC: 3 H positive Front Porch: 1 H
Specifications Controls and Ports - 11

Controls and Ports

User Controls

Front panel: power, brightness, contrast, On-Screen Display
Enter, On-Screen Display Select/Adjust
Additional picture controls available when using the On-Screen
Display
Automatic degauss at power-on; manual degauss by selecting
Degauss in the On-Screen Display
Specifications Physical and Electrical - 12

Physical and Electrical

Power Supply

Size and Weight

Voltage: 100–120 VAC; 220–240 VAC Frequency: 50–60 Hz Power: 120 W maximum
Height: 17.0 in. (431 mm) Width: 16.2 in. (412 mm) Depth: 16.9 in. (428.5 mm) Weight: 37.5 lb. (17 kg)
Specifications Environmental - 13

Environmental

Temperature

Humidity

Altitude

Operating: 50°F to 104°F (10°C to 40°C) Shipping: –4°F to +140°F (–40°C to +60°C) Storage: 32°F to 140°F (0°C to 60°C)
Operating: 20% to 95%, noncondensing
Operating: 0 to 10,000 ft. (0 to 3,048 m) Transit: 0 to 35,000 ft. (0 to 10,670 m)
Specifications Environmental - 14

Power-Saving and Environmental Features

Conforms to the Energy Star program of the United States
Environmental Protection Agency
Complies with TCO 95 as certified by the Swedish confederation of Professional Employees to meet global safety tests and energy­saving features
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Troubleshooting

Apple Multiple Scan 720 Display
Troubleshooting General - 1

General

The Symptom Charts included in this chapter will help you diagnose specific symptoms related to your product. Because cures are listed on the charts in the order of most likely solution, try the first cure first. Verify whether or not the product continues to exhibit the symptom. If the symptom persists, try the next cure. (Note: If you have replaced a module, reinstall the original module before you proceed to the next cure.)
For additional assistance, contact Apple Technical Support.
Troubleshooting First Checklist/ - 2

First Checklist

Important:
be fully operational. Read this checklist before you return a module, and prevent needless module replacement and unnecessary time delays.
Many display modules returned for repair are found to
The Apple Multiple Scan 720 Display is not compatible with all computers.
This display works with both Macintosh and IBM PC-compatible computers. A video card may need to be installed to use this display with some computers. For more information, see the computer manual.
The display works with any computer that has the following timing ranges:
• Horizontal scan rate of 30-70 kHz
• Vertical refresh rate of 48-160 Hz
For best display performance, operate the display in one of the factory-preset screen resolutions listed in the Specifications chapter in this manual.
The CRT raster will not always resemble a perfect rectangle.
CRT tolerances allow for some distortion. Additional distortion can be caused by magnetized metal objects (desks, file cabinets, etc.). Move the unit to a different location if you notice raster bowing or bent raster edges.
Jitter, faint lines, or screen movement can be caused by external interference such as electronic devices and fluorescent lights
Fluorescent lights, other monitors, or electronic appliances such as coffee makers and copy machines can cause raster distortion. Move the unit to another room or building to help determine if external interference is the source of the problem.
Note:
If the raster has shifted up/down or right/left only, adjust it with the user controls. However, keep in mind that if you then move the monitor you may need to readjust the centering controls.
If the display changes (for better or worse) when you move it to another location, the environment is the source of the problem. Relocate the monitor or move the distortion-causing object.
.
Troubleshooting First Checklist/ - 3
A maladjusted screen can mimic the symptoms of deflection board or CRT failures.
By performing the adjustment procedures, you might determine if one or more of the adjustments is the cause of the problem.
CRTs rarely fail.
Needless CRT replacement can be prevented by checking display adjustments, checking the possibility of other defective modules, and accepting small imperfections in screen display.
If you have any doubts about whether a CRT is defective, contact Apple Technical Support.
Troubleshooting Symptom Charts/No Raster - 4

Symptom Charts

No Raster

No raster with LED on 1 Check exterior power cord and video cable connections.
Thumbscrews must be tightened securely. If a video card is used, the video cable must be secured to the card.
2 Adjust brightness and contrast controls located on the front
panel.
3 A screen saver may be activated. Move mouse or press any
key to reactivate the screen.
4 Replace main deflection board and CRT/video board module.
See “Main Deflection and CRT/Video Board Module” in Take Apart chapter. See Adjustments chapter for non-user adjustments that might be necessary after board replacement.
Troubleshooting Symptom Charts/No Raster
(Continued)
- 5
No Raster
No raster with LED off 1 Ensure that power cord is plugged in properly.
2 Check power outlet at the wall by plugging in an electronic
device that works.
3 If the display is plugged into a computer, ensure that
computer is on and power cord firmly connected.
4 Check video cable connections at computer and monitor.
Thumbscrews must be secure. If a video card is used, the video cable must be properly connected.
5 Check cable connection between main deflection board and
control panel board.
6 Replace main deflection board and CRT/video board module.
See “Main Deflection and CRT/Video Board Module” in Take Apart chapter. See Adjustments chapter for non-user adjustments that might be necessary after board replacement.
(Continued)
Troubleshooting Symptom Charts/Video - 6

Video

Screen flickers 1 Check monitor cable connections. Thumbscrews must be
tightened securely. If a video card is used, the video cable must be secured to the card.
2 Check for external interference by moving the monitor to
another location.
3 If using more than one monitor with a computer, move the
monitors so they are at least 18 inches apart.
4 If a video card is used, check the refresh rate. Refresh rates
below 60 Hz may cause flicker. See the video card manual to
raise the refresh rate above 60 Hz. 5 Double-check items 1 through 4. 6 Replace main deflection board and CRT/video board module.
See “Main Deflection and CRT/Video Board Module” in Take
Apart chapter. See Adjustments chapter for non-user
adjustments that might be necessary after board replacement.
Troubleshooting Symptom Charts/Video
(Continued)
- 7
Screen is blurred
Video
Note:
finely-detailed images and small fonts might appear blurry. In this case, try changing the screen resolution.
1 Using the Display Service Utility, select the focus pattern
2 Double-check focus and/or readjust if necessary. 3 Replace main deflection board and CRT/video board module.
(Continued)
If the monitor is set at the highest screen resolution, some
for the Multiple Scan 720/1705, and adjust Focus (the two
top controls on the flyback transformer). Refer to “Focus
Adjustment” in Adjustments chapter.
See “Main Deflection and CRT/Video Board Module” in Take
Apart chapter. See Adjustments chapter for non-user
adjustments that might be necessary after board replacement.
Troubleshooting Symptom Charts/Video
(Continued)
- 8
Video
Raster is too bright 1 Adjust brightness and contrast controls. See “User Controls”
2 Check B+ voltage and adjust if necessary. Refer to “B+
3 Adjust screen control on flyback transformer. Refer to
4 Replace main deflection board and CRT/video board module.
(Continued)
in Adjustments.
Voltage Adjustment” in Adjustments chapter.
“Screen Adjustment” in Adjustments chapter.
See “Main Deflection and CRT/Video Board Module” in Take
Apart chapter. See Adjustments chapter for non-user
adjustments that might be necessary after board replacement.
Troubleshooting Symptom Charts/Video
(Continued)
- 9
Colors are too green, red, or blue, and the screen is unreadable
Video
1 Using the On-Screen Display, check Color Control. Refer to
2 Ensure that the video card or computer video port is good by
3 Ensure that video cable is properly connected and
4 Replace main deflection board and CRT/video board module.
(Continued)
the linked user’s manual in Adjustments chapter.
connecting a known-good monitor.
thumbscrews are secure. If a video card is used, the video
cable must be properly attached to it.
See “Main Deflection and CRT/Video Board Module” in Take
Apart chapter. See Adjustments chapter for non-user
adjustments that might be necessary after board replacement.
Troubleshooting Symptom Charts/Geometry - 10

Geometry

Raster is too short, tall, narrow, or wide
1 Using the On-Screen Display, click Recall. 2 Adjust the width and height of the screen. See “User
Controls” in Adjustments. 3 Double-check the user controls. 4 Replace main deflection board and CRT/video board module.
See “Main Deflection and CRT/Video Board Module” in Take
Apart chapter. See Adjustments chapter for non-user
adjustments that might be necessary after board replacement.
Troubleshooting Symptom Charts/Geometry
(Continued)
- 11
Geometry
Raster is not centered 1 Using the On-Screen Display, click Recall.
2 Check that the distortion is not due to environmental
conditions. Move the monitor. 3 Adjust the horizontal position of screen. See “User Controls”
in Adjustments. If necessary, adjust the raster center at
SW701. See “Horizontal Centering” in Adjustments. 4 Adjust vertical position of screen. 5 Double-check items 1 through 4. 6 Replace main deflection board and CRT/video board module.
See “Main Deflection and CRT/Video Board Module” in Take
Apart chapter. See Adjustments chapter for non-user
adjustments that might be necessary after board replacement.
(Continued)
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T ak e Apart

Apple Multiple Scan 720 Display
Take Apart Safety Guidelines - 1

Safety Guidelines

±
Warning:
vacuum picture tube. To prevent serious injury, review CRT safety in Bulletins/Safety.
±
Warning:
discharging the CRT and setting up an ongoing ground connection.
±
Warning:
sharp sheet-metal edges of the EMI shield, main deflection board chassis, and other metal areas of the monitor assembly.
This product contains high voltage and a high-
Never use a grounding wriststrap until after
When the rear housing is removed, avoid the
Take Apart Safety Guidelines - 2
Important:
housing of the monitor is removed and before replacing a module, you must do the following:
1 Using the CRT discharge
tool (Apple part number 076-0381), discharge the CRT and remove the anode cap.
Whenever the
Take Apart Safety Guidelines - 3
2 Establish an ongoing ground by using a cable with
alligator clips at both ends. Connect one end to the anode aperture, and connect the other end to the braided ground strap that wraps around the CRT.
3 With the CRT discharged and the ongoing ground in place,
wear a grounding wriststrap to prevent equipment damage from static electricity.
Take Apart List of Tools - 4

List of Tools

Required Tools

• Magnetized Phillips screwdriver
• CRT discharge tool (Apple part number 076-0381)
• Sharp knife
• Flat-blade screwdriver
• Wire cutters (for cutting cable ties)
• Plastic cable ties (2)

Optional Tools

• Pen light or flashlight
• Needlenose pliers
Take Apart Tilt-Swivel Monitor Stand - 5

Tilt-Swivel Monitor Stand

No preliminary steps are required before you begin this procedure.
Caution:
grounding wriststrap until after discharging the CRT.
Never use a
Take Apart Tilt-Swivel Monitor Stand - 6
1 Place the monitor face-
down on a protective pad with the monitor stand in front of you.
Take Apart Tilt-Swivel Monitor Stand - 7
2 Position the stand so you
can easily reach around the collar of the stand with both hands.
3 With your thumbs,
press and hold the two tabs. Then slide the monitor stand up and off the bottom chassis.
Note:
Because the monitor is not very heavy, you might need someone to hold the monitor down as you lift off the monitor stand.
Take Apart Tilt-Swivel Monitor Stand - 8
Replacement Note:
four latches on the monitor stand with the slots in the bottom chassis. Then press the stand onto the chassis until the two tabs snap into place.
Align the
Take Apart Rear Housing - 9

Rear Housing

Before you begin, remove the tilt-swivel monitor stand.
±
Warning:
contains high voltage and a high-vacuum picture tube. To prevent serious injury, review CRT safety in Bulletins/Safety.
This product
Caution:
grounding wriststrap until after discharging the CRT.
Never use a
Take Apart Rear Housing - 10
1 With the monitor face-
down, remove the four Phillips screws from the corners of the rear housing.
Take Apart Rear Housing - 11
2 Lift the rear housing
straight up from the monitor assembly. Feed the video cable through the opening in the rear housing.
±
Warning:
housing helps support the weight of the chassis and CRT. When the rear housing is removed, the monitor assembly is less stable. Avoid moving the monitor assembly when the rear housing is not attached.
The rear
Take Apart Rear Housing - 12
Serial Number and Manufacturing Date
Replacement Caution:
The back of the rear housing carries a product ID label that includes the serial number and manufacturing date for the monitor. When you receive a new rear housing part, the product ID label will show blank lines for the serial number and manufacturing date.
To avoid losing this critical information, copy the serial number and manufacturing date onto the blank lines of the product ID label on the new rear housing.
Take Apart EMI Shield - 13

EMI Shield

Before you begin,
• Remove the tilt-swivel
monitor stand
• Remove the rear housing
• Discharge the CRT and
remove the anode cap (refer to Safety Guidelines at the beginning of this chapter)
±
Warning:
contains high voltage and a high-vacuum picture tube. To prevent serious injury, review CRT safety in Bulletins/Safety.
This product
Take Apart EMI Shield - 14
Caution:
grounding wriststrap until after discharging the CRT.
1
Never use a
Caution:
the monitor assembly as you complete this procedure.
±
edges of the EMI shield and chassis can be sharp. Use caution when removing screws or modules.
Remove the six Phillips screws (two in the back and two on each side) from the EMI shield.
Avoid jiggling
Warning:
The metal
Take Apart EMI Shield - 15
2 Flex the sides of the EMI
shield outward to clear any wires or tabs.
3 Lift the shield up and
away from the monitor assembly.
Take Apart EMI Shield - 16
Replacement Note:
replacing the EMI shield screws, ensure the shield is fitted between the two tabs on the back panel and the plastic guides on the chassis sides.
Before
Take Apart Main Deflection Board and CRT/Video Board Module - 17

Main Deflection Board and CRT/ Video Board Module

Before you begin,
• Remove the tilt-swivel
monitor stand
• Remove the rear housing
• Discharge the CRT and
remove the anode cap
• Remove the EMI shield
±
Warning:
contains high voltage and a high-vacuum picture tube. To prevent serious injury,
This product
Take Apart Main Deflection Board and CRT/Video Board Module - 18
review CRT safety in Bulletins/Safety.
Caution:
grounding wriststrap until after discharging the CRT.
Note:
board and CRT/video board module includes the chassis, video cable, TCO board, power board, control panel board, and all associated cables.
Never use a
The main deflection
Take Apart Main Deflection Board and CRT/Video Board Module - 19
1 With the monitor face-
down, disconnect the following cables from the left side of the main deflection board:
• P901 (two brown wires)
• P502 (shielded red and blue wires)
Take Apart Main Deflection Board and CRT/Video Board Module - 20
2 Disconnect the following
cables from the CRT/ video board:
• Two single-pin ground connectors
Important:
the tie wrap that binds the crossed ground cables together
• 2-pin connector P304 (black wires with ferrite bead)
Do not cut
Take Apart Main Deflection Board and CRT/Video Board Module - 21
3 From the right side of
the CRT assembly, disconnect
• 2-wire connector P702 (red and blue yoke wires) from the main deflection board
• 2-wire connector P601 (yellow and orange yoke wires) from the main deflection board
Take Apart Main Deflection Board and CRT/Video Board Module - 22
4 Locate the metal ring
clamp closest to the CRT/video board on the neck of the CRT.
5 If there is any glue on
the clamp or on the Phillips screw, carefully cut or peel it away.
6 Loosen the Phillips
screw.
Take Apart Main Deflection Board and CRT/Video Board Module - 23
7 Use a pen light to check
for glue between the CRT socket and the CRT neck. If glue is there, use a sharp knife to cut through the glue where the CRT socket meets the CRT glass. If necessary, use a needlenose pliers to pull away strips of glue.
Caution:
damaging the CRT, work slowly as you cut the glue, and check that no wires are in the way.
To avoid
Take Apart Main Deflection Board and CRT/Video Board Module - 24
8
Caution:
easily damaged. Gently rock the CRT/video board back and forth while pulling it away from the CRT.
I
f gently rocking and pulling the CRT/video board does not loosen it from the CRT, remove more glue.
CRT pins are
Take Apart Main Deflection Board and CRT/Video Board Module - 25
9 With the CRT/video
board wires still attached, remove the CRT/video board from the CRT neck, and rest it on the main deflection board chassis.
Important:
CRT/video board and main deflection board so that no cables are strained.
Caution:
the monitor assembly.
Support the
Avoid jiggling
Take Apart Main Deflection Board and CRT/Video Board Module - 26
10±Warning:
edges of the chassis are sharp. Use caution when removing screws or modules.
Disconnect the TCO wire connector.
Remove the two Phillips screws and O-ring ground cables at each inner corner of the main deflection board chassis.
The metal
Take Apart Main Deflection Board and CRT/Video Board Module - 27
11 Lift the main deflection
and CRT/video board module away from the CRT.
Replacement Caution:
pinch any wires when positioning the chassis into the front bezel. Before securing the screws, try spinning the front panel knobs to check for proper placement in the bezel.
Do not
Take Apart Main Deflection Board and CRT/Video Board Module - 28
Replacement Note:
pinching or straining cables when replacing the main deflection board and CRT/ video board module.
Avoid
Take Apart Video Cable - 29

Video Cable

Before you begin,
• Remove the tilt-swivel monitor stand
• Remove the rear housing
• Discharge the CRT and remove the anode cap
• Remove the EMI shield
• Remove the main deflection board and CRT/ video board module
±
Warning:
contains high voltage and a high-vacuum picture tube. To prevent serious injury, review CRT safety in
This product
Take Apart Video Cable - 30
Bulletins/Safety.
Caution:
grounding wriststrap until after discharging the CRT.
1 Disconnect the 6-pin
2 If a tie wrap binds the
3 Release the cables from
Never use a
locking-tab connector at P401 from the main deflection board.
wires for P401 and P701, carefully cut the tie wrap.
the cable clamp.
Take Apart Video Cable - 31
4 Remove the single
Phillips screw from the metal clamp at the back panel.
5 Slide the strain relief up
and out of the back panel slot.
Take Apart Video Cable - 32
6 Disconnect the following
cable connectors from the bottom of the CRT/ video board:
• P301
• Single-pin connector
Take Apart Video Cable - 33
7 Lift the video cable away
from the main deflection board and CRT/video board.
Take Apart Front Bezel - 34

Front Bezel

Before you begin,
• Remove the tilt-swivel monitor stand
• Remove the rear housing
• Discharge the CRT and remove the anode cap
• Remove the EMI shield
• Remove the main deflection board and CRT/ video board module
±
Warning:
contains high voltage and a high-vacuum picture tube. To prevent serious injury, review CRT safety in
This product
Take Apart Front Bezel - 35
Bulletins/Safety.
Caution:
grounding wriststrap until after discharging the CRT.
1 Remove the four screws
2 Remove the plastic
Never use a
and lock washers securing the CRT brackets to the bezel.
Note:
Do not disconnect the O-ring cable hooks from the top two CRT brackets and deflection coil.
corner brackets.
Take Apart Front Bezel - 36
3 With both hands, grasp
the CRT by its edges and lift it off of the front bezel.
±
Warning:
CRT by the neck.
Never lift a
Take Apart Front Bezel - 37
Replacement Note:
front bezel module includes the following:
• Power button and spring
• Heat-staked button
• Power LED
• Apple logo
• TCO wire that runs along the interior
Replacement Note:
the CRT inside the front bezel so that the anode aperture is near the top of the bezel. Ensure that the TCO wire is not pinched.
The
Position
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Service Source

Adjustments

Apple Multiple Scan 720 Display
Adjustments Introduction to the On-Screen Display - 1

Introduction to the On-Screen Display

You can adjust the screen image using the buttons and knobs on the front of the display or you can use the controls in the On-Screen Display (OSD). The On-Screen Display lets you fine-tune the screen image.
You can access the On-Screen Display with the front panel user controls.
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User Controls

The front panel controls include:
• Power Button
• Contrast Control
• Brightness Control
• On-Screen Display (OSD) Select/Adjust Control— highlights adjustment choices and selects levels in the On-Screen Display
• On-Screen Display (OSD) Enter Button—turns on the On-Screen Display and enters adjustment choices
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From the On-Screen
Selection Bar
Description
of Highlighted
Control
Display, you can select control icons that represent the following picture­quality adjustments:
• Horizontal Position
H SIZE
Control Icons
SELECT: NEXT:
• Horizontal Size
• Vertical Position
• Vertical Size
• Side Pincushion
• Trapezoid
• Side Pincushion Balance
• Parallelogram
• Tilt
• Moire Reduction
Note: For a complete explanation of each control icon, refer to the linked user’s manual on the next page.
• Video Input Level
• Color Control
• Degauss
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In addition to the picture-quality controls, the On-Screen Display offers the following control icons:
• OSD—Sets the timer for the On-Screen Display window and allows you to change the window’s position on the screen
• Recall—Allows you to restore factory settings
• Language—Selects the language you want the On-Screen Display to appear in
• Information—Shows current settings and signals for the monitor
• Exit—Exits the On-Screen Display
Important:
you can make using the On-Screen Display, click the linked document “MS720 Manual.pdf” at left. The linked document is the user’s manual for the Apple Multiple Scan 720 Display. Refer to Chapter 3, “Using Manual Controls and the On-Screen Display.”
For a complete description of the adjustments
Adjustments Non-User Controls - 5

Non-User Controls

After replacing the main deflection board and CRT/video board module, check the following and adjust the display if necessary:
• B + voltage adjustment
• High voltage (check only; not adjustable)
• Screen adjustment
• Horizontal centering
• Focus adjustment
• Geometry
Perform the adjustments in the order presented here. Refer to the following board diagram for adjustment/check points.
Note:
You do not need to remove the monitor stand for the
procedures in this chapter.
Adjustments - 6

Board Diagram

Adjustment Control Locations
Contrast Control
Brightness Control
VR211VR212
C951
D951
VR901
SW701
Video
Focus 2
Focus 1
Screen
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B+ Voltage Adjustment

Before you begin, refer to the Take Apart chapter to remove the rear housing and EMI shield.
±
Warning:
contains high voltage and a high-vacuum picture tube. To prevent serious injury, review CRT safety in Bulletins/Safety.
±
Warning:
shown. To prevent electric shock, never touch components when the power is on.
This product
Avoid the areas
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Important:
begin, ensure that the power is off and the CRT is discharged.
For this procedure, you need the Display Service Utility, a plastic screwdriver, a voltmeter, and a clip-on test probe with a thin metal hook on the end.
Note:
can be purchased at electronic component supply stores.
Before you
Clip-on test probes
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1 With the power off,
locate potentiometer VR901 near the center of the main deflection board. Place a plastic screwdriver on VR901, but do not adjust it yet.
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2 Locate diode D951 on the
main deflection board (near capacitor C951.)
Notice the cathode (striped end) of D951.
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3 Attach a clip-on test
probe to the cathode (striped end) of diode D951.
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4 Connect the black
(ground) probe of a digital voltmeter to the monitor’s metal chassis.
5 Connect the red
(positive) probe to the clip-on test probe at D951. Ensure that the metal point of the red probe contacts the metal core of the test probe.
6 Leave the voltmeter
turned off.
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7 Turn on the display and
let it warm up for five minutes.
8 Using the control strip,
set the screen resolution to 1024x768 at 75 Hz.
9 Using the Display
Service Utility, select Pattern Selections: Multiple Scan 720/
1705.
Select the crosshatch display pattern with the black background.
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10 Turn on the voltmeter
and use the plastic tool (nonconductive screwdriver) to adjust VR901 so that the voltmeter reads a voltage of 175 VDC ± 0.5 V.
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High Voltage Check

Before you begin, refer to the Take Apart chapter to remove the rear housing and EMI shield.
±
Warning:
warnings, notes, and steps of this procedure before beginning.
±
Warning:
contains high voltage and a high-vacuum picture tube. To prevent serious injury, review CRT safety in Bulletins/Safety.
Read all of the
This product
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1 Turn on the monitor and
let it warm up for five minutes.
2 Using the control strip,
set the screen resolution to 1024x768 at 75 Hz.
3 Using the Display
Service Utility, select Pattern Selections: Multiple Scan 720/
1705.
Select the crosshatch display pattern with the black background.
4 Turn off the monitor and
let it remain off for at
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least two minutes.
Important:
high-voltage probe (Apple part number 076-0392). Use only the Apple high-voltage probe. Other high-voltage probes will not give accurate readings for this procedure.
5 Attach the Apple high-voltage probe to the multimeter
and attach the ground wire to the chassis.
±
cause serious injury. Double-check all multimeter connections before taking the reading.
6 Be sure the monitor is attached to a computer and has
power.
7 Turn on the monitor.
Do not attempt this procedure without the Apple
Warning:
Voltage at the anode, with the power on, can
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8 Carefully insert the probe under the anode cap.
±
Warning: Do not remove the probe from under the
anode cap until power is turned off. Injury or damage to equipment may occur. Probe the anode carefully. Serious damage and injury may occur if the anode cap is knocked off while the CRT is charged.
9 The reading should be 25.5 to 26.5 VDC on the meter.
This is actually 26 kV ± 0.5 kV. Most of the voltage is across the high-voltage probe.
10 Turn off the monitor.
11 Unplug the monitor.
12 Remove the probe from under the anode cap.
Note:
If the voltage is outside the acceptable range after replacing the main deflection board and CRT/video board, contact Apple Technical Support for a whole unit exchange.
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Screen Adjustment

Before you begin, refer to the Take Apart chapter to remove the rear housing.
±
Warning:
contains high voltage and a high-vacuum picture tube. To prevent serious injury, review CRT safety in Bulletins/Safety.
±
Warning:
make adjustments from the rear of the monitor, position a mirror to view the monitor screen. Do not reach around the monitor to adjust
This product
Because you
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the controls.
1 Turn on the display and
let it warm up for five minutes.
2 Using the control strip,
set the screen resolution to 1024x768 at 75 Hz.
3 Using the Display
Service Utility, select Pattern Selections: Multiple Scan 720/
1705.
Select the gray bars display pattern.
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4 With the front panel
control knobs, set
• Brightness control to detent
• Contrast control to maximum
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5 With the room lights
dimmed, use a plastic screwdriver to slowly adjust the Screen control so that the leftmost bar is completely black.
6 Adjust the Screen
control so the second bar appears as black as the leftmost bar. Then adjust so the second bar can be distinguished from the leftmost bar, but the leftmost bar remains black. Only the leftmost bar should be completely black.
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Horizontal Centering

Before you begin, refer to the Take Apart chapter to remove the rear housing.
±
Warning:
contains high voltage and a high-vacuum picture tube. To prevent serious injury, review CRT safety in Bulletins/Safety.
This product
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