3M Multimedia Projector MP8620 User manual

3M Visual Systems Division Printed in U.S.A.
6801 River Place Boulevard ©3M 6/99 78-6970-8988-2 Rev. A
Austin, Texas 78726-9000
MP8620 Multimedia Projector
Service Manual

3MMultimedia Projector MP8620 Table of Contents
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3M 1999 i
MP8620 Table of Contents
1. Adjustments...................................................................................................................................................1-1
1-1. Overview............................................................................................................................................1-1
1-2. Static Control.....................................................................................................................................1-1
1-2-1.Static-Safe Work Environment.............................................................................................1-1
1-3. Machine Identification.......................................................................................................................1-1
1-4. Technician Tools................................................................................................................................1-2
1-5. Returnto Default Settings..................................................................................................................1-3
1-6. Cleaning the LCD Panel.....................................................................................................................1-4
1-6-1.Checking for Dust.................................................................................................................1-4
1-6-2.Cleaning the Dustfrom LCD................................................................................................1-4
1-7. LCD Panel Alignment........................................................................................................................1-5
1-7-3. LCD Verification andAlignment.............................................................................................1-5
1-7-2.LCD Ribbon Cable Installation.............................................................................................1-5
1-7-3.LCD Ribbon Cable Installation.............................................................................................1-6
1-8. Interface/Audio Board Synchronization.............................................................................................1-7
1-9. Lamp Alignment................................................................................................................................1-8
1-9-1.Check the Lamp Alignment..................................................................................................1-9
1-9-2.Align the Lamp.....................................................................................................................1-9
1-10. Timer Information............................................................................................................................1-10
1-10-1.Reset the Lamp Life Indicator.............................................................................................1-10
1-11. Image Adjustments...........................................................................................................................1-11
1-11-1.Adjusting the display resolution and brightness and contrast.............................................1-11
1-11-2.Part 2 – Adjusting the tracking to remove vertical bands in the projectionimage..............1-12
1-11-3.Part 3 – Adjusting the Sync pixel frequency and scanning frequency................................1-13
2. Disassembly/Reassembly.............................................................................................................................2-1
2-1. Overview............................................................................................................................................2-1
2-2. Required Tools...................................................................................................................................2-1
2-3. Steps for Removing Projector Components.......................................................................................2-1
2-3-1.Remove Top Cover...............................................................................................................2-2
2-3-2.Remove EMI Shield..............................................................................................................2-3
2-3-3.Remove Lamp Assembly......................................................................................................2-4
2-3-4.Remove Power Supply..........................................................................................................2-7
2-3-5.Remove Power Distributor....................................................................................................2-8
2-3-6.Remove LCD Assembly........................................................................................................2-9
2-3-7.Remove Lens.......................................................................................................................2-11
2-3-8.Remove Audio Speakers.....................................................................................................2-12
2-3-9.Remove IR Receiver Board.................................................................................................2-13
3. Troubleshooting.............................................................................................................................................3-1
3-1. Overview............................................................................................................................................3-1
3-2. Section Contents.................................................................................................................................3-1
3-3. Direct Failure Troubleshooting Flow Charts......................................................................................3-1
3-3-1.Projector Does Not Power Up...............................................................................................3-2
3-3-2.Lamp Does Not Light............................................................................................................3-3
3-3-3.Projector Image Problem.......................................................................................................3-4
3-3-4.LCD Not Functioning...........................................................................................................3-5
3-3-5.No Sound...............................................................................................................................3-6

3MMultimedia Projector MP8620 Table of Contents
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3M 1999 ii
3-4. General/Projection Image Troubleshooting .......................................................................................3-7
3-4-1. Image is Disturbed or Unstable.............................................................................................3-7
3-4-2. No Computer Image Projected..............................................................................................3-7
3-4-3. No Video Image Projected....................................................................................................3-7
3-4-4. Mouse Does Not Work..........................................................................................................3-8
3-4-5. Image Off Center...................................................................................................................3-8
3-4-6. Cannot Get Entire Image on the Screen................................................................................3-8
3-4-7. Washed Out Image................................................................................................................3-8
3-4-8. Humming Noise. Slowly Passing Horizontal Bars ...............................................................3-9
3-4-9. No Power. Power Shuts Off During Presentation.................................................................3-9
4. T heory and Diagrams ..................................................................................................................................4-1
4-1. Overview............................................................................................................................................4-1
4-2. Theory of Operation...........................................................................................................................4-1
4-2-1. Power Supply Circuit............................................................................................................4-1
4-2-2. Video Input and AD Conversion...........................................................................................4-1
4-2-3. RGB Input and AD Conversion............................................................................................4-2
4-3. Color Theory......................................................................................................................................4-3
4-3-1. Color......................................................................................................................................4-3
4-3-2. Electromagnetic Spectrum ....................................................................................................4-3
4-4. LCD Structure Theory........................................................................................................................4-4
4-4-1. LCD Cells..............................................................................................................................4-4
4-4-2. How Light Passes Through An LCD ....................................................................................4-4
4-4-3. Example Projection...............................................................................................................4-4
4-5. Lamp Theory......................................................................................................................................4-5
4-6. Keystone Correction...........................................................................................................................4-6
4-7. Optical System Layout.......................................................................................................................4-7
4-8. Connection Diagrams.........................................................................................................................4-8
4-9. Wiring Diagrams................................................................................................................................4-9
4-10. Internal Cabling Pinout Tables.........................................................................................................4-10
4-10-1. Interface Board Connector Locations .................................................................................4-10
4-10-2. Audio Board Connector Locations......................................................................................4-11
4-11. Computer/Video/Audio Connections...............................................................................................4-12

3MMultimedia Projector MP8620 Adjustments
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3M 1999 1-1
1. Adjustments
1-1. Overview
Make advanced adjustments to the MP8620 in a clean environment with minimal dust and positive pressure.
This section provides the advanced adjustment procedures needed to maintain a high quality projection image.
There is a specific order that adjustments are to be made and specific tools needed to complete each adjustment.


Important Note
Important: Complete advanced adjustments to a projector only when the
machine settings fall outside of the allowable tolerances for that
adjustment, or when instructed to do so by another procedure.
1-2. Static Control
The circuit boards in the MP8620 are very sensitive to static energy. A simple static charge can ruin a circuit
board instantly. Because of this, it is essential that you complete all repairs in a static-safe work environment.
1-2-1. Static-Safe Work Environment
A properly grounded floor mat, table mat and adjustable wrist strap with grounding cord are needed for
complete static protection.
3M recommends any of the following workstation grounding kits:
 3M™ Workstation Grounding Kit Model 8011
 3M™ Workstation Grounding Kit Series 8020
 3M™ Workstation Grounding Kit Series 8030
For your nearest distributor or to order, call 1-800-328-1368.
1-3. Machine Identification
To avoid incorrect adjustments, verify the model and version of the projector prior to making any adjustments.
Different versions have unique adjustment requirements. The serial number for MP8620 is located on the back
of the projector.

3MMultimedia Projector MP8620 Adjustments
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3M 1999 1-2
1-4. Technician Tools
Test Generator: 3M recommends the Quantum Data™ 801GX
Video Test Generator (shown to right) or Extron™ VTG200 Video
Test Generator be used for all advanced adjustment procedures. Use
to input a test pattern prior to adjustments.
External Power Supply: Used to check the audio interface PCB’s.
Service Interface Cable: Used to connect the original disassembled
power supply with the interface board.
LCD Alignment Tool: Used to check that the LCD alignment is at an 8 degree angle.
Backlight Light Source: Used to check the disassembled LCD unit without the original machine lamp source.
Voltmeter: Used to measure the voltage at particular test points. 3M recommends the Fluke™ model 87
Oscilloscope (100 MHz): Used to check the video signals horizontal and vertical synchronization and the video
board clock.
Torx Drivers: Use to remove mounting bolts.
White Silk Gloves: Used to keep skin oils away from the lamp and LCD panel.

3MMultimedia Projector MP8620 Adjustments
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3M 1999 1-3
1-5. Return to Default Settings
1. Power down the projector and turn the main power switch to off.
Press and hold both the Enter button and the Down Arrow button on the control panel
2. Turn the main power switch to on. The default settings are restored and the following message appears:
Parameter Factory Settings Restored.
Resetting a projector to its default factory setting may resolve a “no input detected” error message for an RGB
or video input device.

3MMultimedia Projector MP8620 Adjustments
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3M 1999 1-4
1-6. Cleaning the LCD Panel
Dust particles can accumulate on the glass covering the LCD panel causing spots on the projection image.
Periodic cleaning is necessary to maintain a high quality projection image.
1-6-1. Checking for Dust
Test for dust on the LCD panel by projecting a white image:
3. With the projector off, plug in the video test generator to an RGB terminal jack located on the back side of
the MP8620.
4. Use the video test generator to input the color White with a timing signal set to SVGA VESA (60).
Note
The voltage settings for each input color need to be programmed into the video
test generator. Refer to the video test generator user’s guide for further
assistance.
5. Turn the main power switch to the on position.
6. Look for dust particles on the projection image.
Note
Remove any dust from the outside of the projection lens with a lint-free cloth. If
dust remains on the projection image, the LCD panel needs to be cleaned.
1-6-2. Cleaning the Dust from LCD
If dust particles can be seen on your projection image:
1. Turn off the main power switch of the projector and unplug the power cord.
2. Remove the LCD module assembly. (Refer to the appropriate Disassembly/Reassembly procedures).
3. Use a dust blower or compressed air to blow air on the LCD panel. Do not exceed 40 PSI.
4. If dust is still visible wipe the LCD panel with a chamois swab or a lint-free cloth from the 3M LCD
cleaning kit.
Note
Use extreme care when cleaning any optics device. Special gelatin coatings can
be scratched very easily.
5. Use a lighted magnifier with a black background to check for streaks.
6. Replace the LCD panel, reassemble the projector and recheck the projection image for dust by projecting a
blank white image.
7. If dust still remains complete steps 1-6 again. If dust is gone, complete a LCD panel alignment.

3MMultimedia Projector MP8620 Adjustments
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3M 1999 1-5
Alignment
Lever
1-7. LCD Panel Alignment
Periodic LCD panel alignment is necessary to maintain a high quality projection image.
1-7-1. LCD Verification and Alignment
Use the LCD Alignment tool (DY-0205-1508-5) to verify the
8° angle of the LCD unit.
1. Measure the angle between the bottom and the assembly
surface of the LCD on the linkage side.
2. If the angle is not 8°, reform the alignment lever to obtain
the proper 8° setting.
It may be needed to readjust the microswitch which is in
contact with to the LCD unit. This switch has to be activated
when the LCD is at the 8° angle.
1-7-2. LCD Ribbon Cable Installation
Installing a new LCD ribbon cable is done using the following steps:
1. Gently pull out the white plastic clamp on the LCD and interface board connectors to release the LCD
ribbon cable.
2. Insert one end of the new ribbon cable into the LCD connector. The blue side of the cable should be facing
up.
3. Insert the other end of the new ribbon cable into the interface board connector. The blue side of the cable
should be facing down.
4. Lock the white plastic clamps into place on both the LCD connector and the interface board connector.
5. Use the old cable as a pattern to place the appropriate bends in the new cable.
If a connector clamp is broken:
1. Order a complete connector (DY-0205-1512-7).
2. Remove the plastic portion from the new connector and replace the broken part.
3. If the connector can not be repaired in this way, the LCD or interface board may need to be replaced.

3MMultimedia Projector MP8620 Adjustments
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3M 1999 1-6
1-7-3. LCD Ribbon Cable Installation
Installing a new LCD ribbon cable is done using the following steps:
1. Gently pull out the white plastic clamp on the LCD and Interface board connectors to release the LCD
ribbon cable.
2. Insert one end of the new ribbon cable into the LCD connector. The blue side of the cable should be facing
up.
3. Insert the other end of the new ribbon cable into the interface board connector. The blue side of the cable
should be facing down.
4. Lock the white plastic clamps into place on both the LCD connector and the Interface board connector.
5. Use the old cable as a pattern to place the appropriate bends in the new cable.
If a connector clamp is broken:
Order a complete connector (DY-0205-1512-7).
Remove the plastic portion from the new connector and replace the broken part.
If the connector can not be repaired in this way, the LCD or interface board may need to be replaced.

3MMultimedia Projector MP8620 Adjustments
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3M 1999 1-7
3.4 Volts


0.1
Label PCB
Trim
1-8. Interface/Audio Board Synchronization
The interface board or the audio board must be in sync. If either one or both are changed, complete the
synchronization procedure.
1. Remove the power supply board using the procedure listed in the Disassembly/Reassembly section.
2. Remove the cooling fan and bracket by removing the two screws.
3. Remove three additional screws on the power supply base plate.
4. Tip up the base plate toward the lamp housing to remove it.
5. Reconnect the power supply to the machine with the 3-pin connector, or reconnect the external power
supply (DY-0205-1509-3) to the machine with the 3-pin connector.
6. Connect the interface board to the power board with the Service Interface Cable (DY-205-1500-1).
7. Place a cover over the power supply board to prevent damage or injury.
Because the power supply board is fully energized in the next step, it is essential that a cover is placed over the
board to prevent injury.
8. Power up the projector.
9. Measure the voltage of pin 9 on the test block. This
connector is nearest the EPROM. Pin 1 is closest to
the EPROM. The voltage should be 3.4 Volts

.01.
10. If the voltage reading of pin 9 on the test block is
outside the allowable tolerance, adjust the trim
potentiometer located in a small hole in the audio
board until the voltage reading is within tolerance.
11. When finished with the adjustment, reassemble
the projector.
Use extra care when replacing the power supply
base plate, the LCD cable can be damaged very
easily.
Power supply
base
p
late
Power supply
board
Cooling fan bracket
Cooling fan

3MMultimedia Projector MP8620 Adjustments
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3M 1999 1-8
Tripletlens
1-9. Lamp Alignment
A poorly aligned lamp can reduce the brightness or the uniformity of the projection image. To ensure that the
projector is producing the best possible image lamp alignment should be checked regularly.
1-9-1. Check the Lamp Alignment
1. With the projector off, remove the lamp assembly using
the procedure listed in the Disassembly/Reassembly
section.
2. Hold the lamp assembly and look through the condenser
at an angle perpendicular to the condenser lens.
3. The lamp should be aligned using the reflection image on
the lamp reflector. The image of the lamp should be
slightly above or slightly below the lamp.
4. If not, this position can be changed by turning
the two adjustment screws below the lamp
sockets.
5. Verify the lamp alignment by powering up the
projector and viewing the image of the lamp on
the screen. This can be done by holding a triplet
lens in front of the projector lens .
6. Visually check to make sure the image of the lamp arc is positioned correctly:
b. Im age of
hidd
by
l
c. Im age
fd
la m p a rc to
f
Incorrect lamp
alignment:
Image of arc
hidden by lamp Images of arcs
too far apart
Image of
arc
Correct lamp
ali
g
nment:
Image of
reflected
arc
Reflected image
of lamp slightly
below

3MMultimedia Projector MP8620 Adjustments
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3M 1999 1-9
1-9-2. Align the Lamp
1. With the projector off, adjust the lamp up or down by turning the two adjustment screws mounted on springs
under the lamp socket.
Note
If the arcs are too close, the lumen output will be reduced. If the arcs are to far
apart the image uniformity will be affected.
2. Verify the lamp alignment by powering up the projector and viewing the image of the lamp on the screen by
holding a triplet lens in front of the projector lens.
3. Repeat the above two steps until the lamp is aligned correctly.

3MMultimedia Projector MP8620 Adjustments
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3M 1999 1-10
1-10. Timer Information
A lamp life indicator is located under the Option sub-menu. If the indicator bar for the sub-menu item Lamp is
Green the lamp is good. When the bar turns red or the projection image appears dark, the lamp and air filter
should be replaced.
1-10-1.Reset the Lamp Life Indicator
1. Under the Option sub-menu select the sub-menu item Lamp and press Enter.
4. Follow the instructions in the Help Window.
5. Press the Enter button and the Up Arrow button on the control panel for confirmation.

3MMultimedia Projector MP8620 Adjustments
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3M 1999 1-11
1-11. Image Adjustments
1-11-1. Adjusting the display resolution and brightness and contrast.
1. Display the PC (RGB) input device projection image.
6. Boot up Microsoft Windows. Go to Control Panel and adjust the desktop background to an even black-and-
white raster. Or, display a projection image with black and white colors.
7. Press the Menu button on the projector to display the main menu.
8. Press the up/down Arrow buttons on the projector or the Control Stick on the remote control up/down to
highlight the Setup sub-menu.
9. Press the Enter button to select the Setup sub-menu. The current display resolution is displayed in the title
block of the Setup menu. For example 640 x 480. Change the display resolution if desired.
10. Confirm your selection by pressing the Enter button.
11. Press the up/down Arrow buttons on the projector or move the Control Stick on the remote control to
select the Palette sub-menu item.
12. Press the left/right Arrow buttons on the projector or the Control Stick on the remote control left/right to
reduce the chromatic resolution from the default that is 16.7 million colors to 64.
13. Press the up/down Arrow buttons on the projector or move the Control Stick on the remote control to
select the Pixels sub-menu item.
14. Press the left/right Arrow buttons on the projector or move the Control Stick on the remote control
left/right to increase or decrease the number of pixels in the display. Select 800 x 600.
15. Select the menu item Brightness and correct the setting so that white areas are projected with maximum
intensity.
16. Select the menu item Contrast and correct the setting so that the gray areas are clearly visible.
17. Press the Menu button to exit the sub-menu and return to the main menu.
18. A message will display in the help window asking you to confirm the changes made in the sub-menu. Press
Enter to confirm.
19. Press the Menu button to exit the main menu display and return to the projected image.

3MMultimedia Projector MP8620 Adjustments
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3M 1999 1-12
1-11-2. Part 2 – Adjusting the tracking to remove vertical bands in the projection image.
1. Test the tracking using a MS Excel spreadsheet projection image or equivalent. If vertical interference can
be seen, then the tracking needs adjustment.
2. Press the Menu button on the projector to display the main menu.
3. Press the up/down Arrow buttons on the projector or move the Control Stick on the remote control
up/down to highlight the Setup sub-menu.
4. Press the Enter button to select the Setup sub-menu.
5. Press the up/down Arrow buttons on the projector or move the Control Stick on the remote control to
select the Tracking sub-menu item.
6. Press the left/right Arrow buttons on the projector or move the Control Stick on the remote control
left/right to reduce the amount of interference.
7. The direction of adjustment is correct when the number of lines decreases. The setting is optimal when no
interference lines can be seen.
8. Press the Menu button to exit the sub-menu and return to the main menu.
9. A message will display in the help window asking you to confirm the changes made in the sub-menu. Press
Enter to confirm.
An automatic setting of tracking can be called up by pressing theEnter button. This may not work if the
projection image is a uniform pattern.

3MMultimedia Projector MP8620 Adjustments
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3M 1999 1-13
1-11-3. Part 3 – Adjusting the Sync pixel frequency and scanning frequency.
This adjustment removes any “fuzziness or flicker” in the projection image.
1. Press the Menu button on the projector to display the main menu.
2. Press the up/down Arrow buttons on the projector or move the Control Stick on the remote control
up/down to highlight the Setup sub-menu.
3. Press the Enter button to select the Setup sub-menu
4. Confirm your selection by pressing the Enter button.
5. Press the up/down Arrow buttons on the projector or move the Control Stick on the remote control to
select the Sync sub-menu item.
6. Press the left/right Arrow buttons on the projector or move the Control Stick on the remote control
left/right to reduce the amount of “fuzziness or flicker” in the projection image.
An automatic setting of synchronization can be called up by pressing the Enter button.
7. Complete fine adjustments to the brightness and contrast settings if minor interference still remains.
Press the Menu button to exit the sub-menu and return to the main menu.
8. Complete fine adjustments to the brightness and contrast settings if minor interference still remains.
9. Press the Menu button to exit the sub-menu and return to the main menu.
10. A message will display in the help window asking you to confirm the changes made in the sub-menu. Press
Enter to confirm.
11. Press the Menu button to exit the main menu display and return to the projected image.
Before
After

3MMultimedia Projector MP8620 Disassembly/Reassembly
3M 1999 2-1
2. Disassembly/Reassembly
2-1. Overview
Disassembly and reassembly of the MP8620 is done using the reference photographs and the step-by-step
procedures that follow. Many component disassembly steps build upon previous disassembly steps. Refer to
the previous disassembly steps as needed.
For general machine operation instructions including air filter or lamp replacement, refer to the Operator’s
Guide.
To avoid electrical shocks, unplug projector power cord before performing any
maintenance to electrical components.
To avoid burns to fingers, allow projector lamp and internal projector components to
cool off prior to lamp removal or disassembly.
2-2. Required Tools
An entire disassembly and reassembly can be completed with the following tools:
•Phillips screwdriver (#1 magnetic long shaft)
•Standard screwdriver (3/16 in. or ¼ in. blade)
2-3. Steps for Removing Projector Components
Removal topics include:
•Top cover
•EMI shield
•Lamp Assembly
•Power Supply
•Power Distributor
•LCD Assembly
•Lens
•Audio Speakers
•IR Receiver board
√√ Note
If performing a complete disassembly, record lamp time.
!
Caution
!
WARNING

3MMultimedia Projector MP8620 Disassembly/Reassembly
3M 1999 2-2
1
2
34
2-3-1. Remove Top Cover
To avoid electrical shocks, unplug projector
power cord before performing any maintenance
to electrical components.
To avoid burns to fingers, allow projector lamp
and internal projector components to cool off prior
to lamp removal or disassembly.
1. Lift the two cover latches & lift the cover into the
projection position.
2. Carefully pry off two (2) cover hinges.
3. Lift rear of top cover up.
4. Slide top cover forward toward projection lens
5. Reassemble in reverse order.
!
Caution
!
WARNING

3MMultimedia Projector MP8620 Disassembly/Reassembly
3M 1999 2-3
1
2
2-3-2. Remove EMI Shield
To avoid electrical shocks, unplug projector
power cord before performing any maintenance
to electrical components.
To avoid burns to fingers, allow projector lamp
and internal projector components to cool off prior
to lamp removal or disassembly.
Remove top cover.
1. Remove two (2) screws.
2. Lift EMI shield up to remove.
3. Reassemble in reverse order.
!
Caution
!
WARNING

3MMultimedia Projector MP8620 Disassembly/Reassembly
3M 1999 2-4
1
2
3
4
5
2-3-3. Remove Lamp Assembly
To avoid electrical shocks, unplug projector
power cord before performing any maintenance
to electrical components.
To avoid burns to fingers, allow projector lamp
and internal projector components to cool off prior
to lamp removal or disassembly.
1. Remove two (2) screws from bottom of base.
2. Depress lock tab and slide cover to remove.
3. Lift latch to release lamp panel and lower panel to the
open position.
√√ Note
Do not touch lamp glass with fingers. Oil from
fingers can reduce lamp life.
4. Release wire from wire holder.
5. Return lamp panel to the closed position.
6. Remove EMI shield. (See Section 2-3-2.)
!
Caution
!
WARNING