Panasonic PTL785U - LCD PROJECTOR UNIT User manual

©2004 Matsushita Electric Industrial Co., Ltd. All
rights reserved. Unauthorized copying and
distribution is a violation of law.
PT-L785U
PT-L785E
LCD Projector
ORDER NO. VED0407354C0
D10

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PT-L785U / PT-L785E

1 Safety Precautions 51.1. General Guidelines 5
CONTENTS
Page Page
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1.2. Leakage Current Check 5
1.3. UV Precaution and UHM Lamp Precautions 5
2 Ext Option 6
2.1. Procedure to enter EXT OPTION 6
2.2. EXT OPTION Menu and Functions 6
2.3. Canceling EXT OPTION 6
3 Self-Check Mode 6
3.1. Procedure to enter the self-check mode 6
3.2. Self Check Display and Contents 7
3.3. Canceling the self-check mode 7
4 Service Mode 7
4.1. Procedure to enter the service mode 8
4.2. Canceling the service mode 8
5 Flicker Adjustment Mode 8
5.1. Procedure to enter the adjustment mode 8
5.2. Adjustment Display and Contents 8
5.3. Canceling the flicker adjustment mode 8
6 Using the SERIAL Connector 8
6.1. Connection 9
6.2. Pin Layout and Signal Names for SERIAL Connector 9
6.3. Communication Settings 9
6.4. Basic Format 9
6.5. Control / Query Commands 10
6.6. Communication Cable Specifications 12
6.7. Signal Selector Connecting Cable Specifications 13
7 Using the REMOTE Connector 13
7.1. Control Method 13
7.2. Pin Layout and Signal Names for REMOTE Connector
13
7.3. Switching the Input Mode 13
7.4. Caution and Limitations 13
8 Disassembly Instructions 14
8.1. Printed Circuit Board and Main Parts Location 14
8.2. Removal of Upper Case 15
8.3. Removal of S-P.C.Board 15
8.4. Removal of R-P.C.Board 15
8.5. Removal of A-P.C.Board 15
8.6. Removal of P-Module) 16
8.7. Removal of Ballast Unit (B / Q-Module) 17
8.8. Removal of K-Module 17
8.9. Removal of Analysis Block 18
8.10. Removal of LCD Block 19
8.11. Replacement of LCD Panel 19
8.12. LCD Panel Discrimination 20
8.13. LCD Panel Combination 20
8.14. Replacement of Polarizer 21
8.15. Replacement of PBS Array (Analysis Block) 21
8.16. Removal of lamp Unit 22
9 Measurement and Adjustments 23
9.1. Adjustment Procedure Flowchart 23
9.2. Cautions for Adjustment 23
9.3. Setting Before Adjustment 23
9.4. Convergence Adjustment 23
9.5. Lighting Area Adjustment 24
9.6. Software for Adjustment 26
9.7. Flicker Adjustment 27
9.8. RGB Input Level Adjustment 28
9.9. Date / Time Setting 28
10 Troubleshooting 29
11 Interconnection Block Diagram 43
11.1. Interconnection Block Diagram (1 / 2) 43
11.2. Interconnection Block Diagram (2 / 2) 44
12 Block Diagram 45
12.1. Power Supply 45
12.2. Signal Processing (1 / 3) 46
12.3. Signal Processing (2 / 3) 47
12.4. Signal Processing (3 / 3) 48
13 Schematic Diagram 49
13.1. A-P.C.Board (1 / 8) 50
13.2. A-P.C.Board (2 / 8) 51
13.3. A-P.C.Board (3 / 8) 52
13.4. A-P.C.Board (4 / 8) 53
13.5. A-P.C.Board (5 / 8) 54
13.6. A-P.C.Board (6 / 8) 55
13.7. A-P.C.Board (7 / 8) 56
13.8. A-P.C.Board(8 / 8) 57
13.9. B-Module (1 / 2) 58
13.10. B-Module (2 / 2) 59
13.11. J-P.C.Board, S-P.C.Board 60
14 Circuit Boards 61
14.1. A-P.CBoard (Foil Side) 61
14.2. A-P.CBoard (Component Side) 62
14.3. J-P.C.Board / S-P.C.Board 63
15 Terminal guide of ICs and transistors 65
16 Exploded Views 66
17 Replacement Parts List 70
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PT-L785U / PT-L785E

1 Safety Precautions
1.1. General Guidelines
· For continued safety, no modification of any circuit must be
attempted.
· Unplug the power cord from the power outlet before
disassembling this projector.
· It is advisable to use an isolation transformer in the AC
power line before the service.
· Observe the original lead dress during the service. If a short
circuit is found, replace all the parts overheated or
damaged by the short circuit.
· After the service, all the protective devices such as
insulation barriers, insulation papers, shields, and isolation
R-C combinations must be properly installed.
· After the service, check the leakage current to prevent the
customer from getting an electric shock.
1.2. Leakage Current Check
1.Prepare the measuring circuit as shown in Fig.1.
Be sure to use a voltmeter having the performance
described in Table 1.
Fig. 1
Table 1
Fig. 2
2.Assemble the circuit as shown in Fig. 2. Plug the power
cord in a power outlet.
3.Connect M1 to T1 according to Fig. 2 and measure the
voltage.
4.Change the connection of M1 from T1 to T2 and measure
the voltage again.
5.The voltmeter must read 0.375 V or lower in both of steps
3 and 4. This means that the current must be 0.75 mA or
less.
6.If the reading is out of the above standard, the projector
must be repaired and rechecked before returning to the
customer because of a possibility of an electric shock.
1.3. UV Precaution and UHM Lamp
Precautions
· Be sure to unplug the power cord from the power outlet
when replacing the lamp.
· Because the lamp reaches a very high temperature during
its operation, wait until it cools completely when replacing
the Lamp Unit.
· The lamp emits small amounts of UV-radiation, avoid direct-
eye contact with the light.
· Because the high pressure lamp involves a risk of
explosion, never touch the lamp wire lead during the
service. (See Fig. 3)
Fig.3
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2 Ext Option
This projector has EXT OPTION in addition to standard on-screen menus.
· There are SELF CHECK and TEST PATTERN (Service Mode) for service, etc.
2.1. Procedure to enter EXT OPTION
1.Press "MENU" button on the main unit or remote control unit to display "MENU" screen.
2.Select "OPTION" menu using " " and/or " " buttons.
3.Select "OSD" and press "ENTER" button 3 seconds or longer.
MENU →OPTION →OSD
2.2. EXT OPTION Menu and Functions
· FREEZE MESSAGE
Switching ON/OFF "FREEZE" on-screen display
· FAN FULL MODE
Switching ON "FAN FULL MODE", the rotation level of the fan becomes high-speed rotation (fixed). Moreover, when "FAN
FULL MODE" is ON, changing "FAN CONTROL" in OPTION menu becomes impossible (setting FAN FULL MODE is given
priority more than FANCONTROL).
Caution:
− − −
− Switching ON "FAN FULL MODE" while used usually (at an elevation of lower than 1 400 m), this may cause
malfunctions.
· SELF CHECK
To enter the self-check mode
· TEST PATTERN
To enter the service mode
· FLICKER ADJ
To enter the flicker adjustment mode
· MASK PLUSE
To receive a special signal, the signal is specially processed.
− − −
− When the signal of YPbPr480i or YPbPr576i is inputted, the synchronization might become unstable. It might be stable
when MASK PULSE is set to SPECIAL.
2.3. Canceling EXT OPTION
Press "MENU" button on the main unit or remote control unit.
3 Self-Check Mode
This mode is used to narrow down the location of the failure.
3.1. Procedure to enter the self-check mode
Select "SELF CHECK" on "EXT OPTION" menu and press "ENTER" button on the main unit or remote control unit.
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3.2. Self Check Display and Contents
3.3. Canceling the self-check mode
Press "MENU" button on the main unit or remote control unit.
4 Service Mode
This mode is used to display five kinds of test patterns [Horizontal lines, Vertical lines, Dots, Crosshatch and White (No pattern)]
in the four colors (White, Red, Green and Blue).
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Note:
· On the service mode, displays above patterns by each color without test equipment such as PC or SG. Use the service
mode for simplified adjustments by your eyes and so on.
4.1. Procedure to enter the service mode
Select "TEST PATTERN" on "EXT OPTION" menu and press "ENTER" button on the main unit or remote control unit.
Note:
· In the service mode, pressing the up-arrow " " or down-arrow " " button allows the test pattern selection and
theleft-arrow " " or right-arrow " " button the color selection (White / Red / Green / Blue).
4.2. Canceling the service mode
Press "MENU" button on the main unit or remote control unit.
5 Flicker Adjustment Mode
If replacing the optical parts (Analysis / LCD / Lens block) of this projector, enter the flicker adjustment mode and minimize the
flicker.
Also when replacing the analysis block or A-P.C.Board (assembly), execute 9.7. "Flicker Adjustment".
5.1. Procedure to enter the adjustment mode
Select "FLICKER ADJ" on "EXT OPTION" menu and press "ENTER" button on the main unit or remote control unit.
Note:
"DESK setting (blue)" is displayed when entering the adjustment mode.
5.2. Adjustment Display and Contents
· Setting value is increased and decreased with the right-arrow " " and left-arrow " " buttons.
"": Decrease, " ": Increase
− − −
− Adjust the setting value to minimize the flicker on the screen.
− − −
− Execute the adjustment by 6 patterns below.
· The pattern (adjustment display) is switched with the up-arrow " " and down-arrow " " buttons.
"": Forward direction, " ": Reverse direction
− − −
− There are 6 patterns of "DESK setting (blue)", "DESK setting (red)", "DESK setting (green)", "CEILING setting (blue)",
"CEILING setting (red)" and "CEILING setting (green)".
− − −
− The setting value is saved into this projector when the pattern is switched.
5.3. Canceling the flicker adjustment mode
Press "MENU" button on the main unit or remote control unit.
Note:
When "MENU" button is pressed, the setting value at that time is saved into this projector and the adjustment mode is canceled.
6 Using the SERIAL Connector
The serial connector which is on the side connector panel of the projector conforms to RS-232C standard. This projector can
be controlled by a PC which is connected as shown in "6.1. Connection". For controlling this projector by aPC, requires
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PT-L785U / PT-L785E

Pin No Signal Name Contents
1--- NC
2 TXD Transmit data
3 RXD Receive data
4--- NC
5 GND Ground
6 DSR
7 CTS Connected internally
8 RTS
9--- NC
communication software on the market, and inputs control commands according to communication settings and basic format
below.
6.1. Connection
Note:
Use a proper communication cable which is suitable for the PC to connect SERIAL connector and the PC.
6.2. Pin Layout and Signal Names for SERIAL Connector
6.3. Communication Settings
Signal Level Contents Description
Sync. method Asynchronous Synchronizes every 1 character (8 bits)
Baud rate Conforms to 9 600 bps Data transfer speed
Parity RS-232C None Error detection method
Character length standard 8 bits Number of bit composing 1 character
Stop bit 1 bit Uses stop bit when asynchronous method
X parameter Not used
S parameter Not used
6.4. Basic Format
The data sent from the PC to the projector is transmitted in the format shown below.
Notes:
· If sending multiple commands, check that a call back has been received from the projector for 1 command before sending
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Control Commands
the next command.
· When a command which does not require parameters is sent, the colon (:) is not required.
6.5. Control / Query Commands
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Query Commands
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PT-L785U / PT-L785E

Parameters
[Example]
When controls the audio volume to +30 by a PC
(Sends commands as the following:)
· When a command which does not require parameters is sent, the colon (:) is not required.
6.6. Communication Cable Specifications
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6.7. Signal Selector Connecting Cable Specifications
When connecting to a signal selector (ex. TW-SWS62J), use a cable with specifications below.
Connecting method: Connects a video signal cable from the signal selector to "VIDEO IN", and an RGB signal cable to "RGB1 IN".
Note:
Set VP control terminal switch of the signal selector to VP TYPE "B".
7 Using the REMOTE Connector
7.1. Control Method
Controls by each terminal of the REMOTE connector is grounded (connect to pin 1).
7.2. Pin Layout and Signal Names for REMOTE Connector
The connector used is the same as "SEREIAL connector".
Note:
Refer to section 6.2. "Pin Layout and Signal Names for SERIAL Connector" for the pin layout.
7.3. Switching the Input Mode
The input mode can be switched by combining the input signal select terminals (pins 3, 5 and 6).
7.4. Caution and Limitations
· Do not ground pins 2, 3, 5 and 6, when the remote control is disable (pin 9 is open). The projector will ignore signals from the
remote control unit.
· The POWER, RGB and VIDEO buttons will not operate when the remote control is enable (pin 9 is grounded).
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8 Disassembly Instructions
Warning:
· Be sure to unplug the power cord from the power outlet before disassembling this projector.
Caution:
· While turning over a printed circuit board, be sure to put a insulating material under it to prevent a short circuit.
· Printed circuit boards and wires must not be pulled forcibly, but be handled carefully.
· Connectors also must be handled carefully.
· After repairing this projector, be sure to put back the wires and connectors to the original condition.
8.1. Printed Circuit Board and Main Parts Location
Electrical Parts
Optical Parts
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8.2. Removal of Upper Case
1.Turn the projector upside down.
2.Loosen the 2 screws until they idle, open the air outlet port.
3.Unscrew the 7 screws.
4.Return the projector to the normal position.
Note:
· Pay attention the air outlet port must not be fixed.
5.Open the carrying handle.
6.Remove the upper case.
8.3. Removal of S-P.C.Board
1.Remove the upper case according to the section 8.2.
"Removal of Upper Case".
2.Unscrew the 4 screws and remove the S-P.C.Board.
8.4. Removal of R-P.C.Board
1.Remove the upper case according to the section 8.2.
"Removal of Upper Case".
2.Unscrew the 1 screw and remove the R-P.C.Board.
8.5. Removal of A-P.C.Board
1.Remove the upper case according to the section 8.2.
"Removal of Upper Case".
2.Unscrew the 3 screws fixing the terminal cover.
3.Unscrew the 3 screws and remove the speaker (R) with the
metal fittings.
4.Unscrew the 5 screws fixing the A-P.C.Board block.
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5.Disconnect the connectors from/to the A-P.C.Board.
6.Take the A-P.C.Board block out from the main unit of the
projector.
<Disassembling the A-P.C.Board Block>
7.Unscrew the 2 screws and remove the heatsink of A-
P.C.Board.
8.Unscrew the 2 screws and remove the speaker (L).
9.Unscrew the 1 screw and remove the WL-fittings.
<Removing the J-P.C.Board>
10.Unscrew the 2 screws and remove the terminal cover.
11.Unscrew the 2 hex-head screws and 2 ornament screws.
12.Unscrew the 2 screws and remove the J-P.C.Board.
8.6. Removal of P-Module)
1.Take the A-P.C.Board block out according to the steps 1
through 6 in the section 8.5. "Removal of A-P.C.Board".
2.Loosen the 2 screws until they idle and remove the lamp
unit.
3.Unscrew the 4 screws and remove the S-P.C.Board.
4.Unscrew the 2 screws and remove the ground fittings.
5.Unscrew the 2 screws and remove the exhaust fan2.
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6.Unscrew the 2 screw and remove the socket cover, then
remove the lamp unit terminal.
7.Unscrew the 3 screw and remove the power block.
8.Unscrew the 3 screw and separate the power unit and
ballast unit.
9.Remove the 1 screw.
10.While pressing to shut each hook of the 3 resinous stands
(spacers), remove the P-Module.
8.7. Removal of Ballast Unit (B / Q-
Module)
1.Remove the power block, then separate the power unit and
the ballast unit according to the steps 1 through 8 in the
section 8.6. "Removal of P-Module".
2.While pressing to shut each hook of the 4 resinous stands
(spacers), remove the B/Q-Module.
8.8. Removal of K-Module
1.Remove the analysis block according to the steps 1 through
8 in the section 8.9. "Removal of Analysis Block".
2.Unscrew the 3 screws and remove the filter block (K-
Module) .
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Note:
· Under this condition, the repair and the parts
replacement of the K-Module are possible.
8.9. Removal of Analysis Block
1.Take the A-P.C.Board block out according to the steps 1
through 6 in the section 8.5. "Removal of A-P.C.Board".
2.Loosen the 2 screws until they idle and remove the lamp
unit.
3.Unscrew the 4 screws and remove the S-P.C.Board.
4.Unscrew the 2 screws and remove the ground fittings.
5.Unscrew the 1 screw and remove the bimetal holder.
6.Unscrew the 2 screws and remove the socket cover, then
remove the lamp unit terminal.
7.While pressing the lens release button, fully turn
counterclockwise the lens and pull it out.
8.Unscrew the 3 screws and take the analysis and LCD
blocks out.
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9.Unscrew the 2 screws and remove the LCD block.
8.10. Removal of LCD Block
1.Take the A-P.C.Board block out according to the steps 1
through 6 in the section 8.5. "Removal of A-P.C.Board".
2.Unscrew the 4 screws and remove the S-P.C.Board.
3.Unscrew the 2 screws and remove the ground fittings.
4.While pressing the lens release button, fully turn
counterclockwise the lens and pull it out.
5.Unscrew the 4 screws and remove the LCD block.
8.11. Replacement of LCD Panel
1.Remove the LCD block according to the section 8.10.
"Removal of LCD Block".
2.Unscrew the 4 screws and replace the LCD panel. (Remove
the old LCD panel and install a new one.)
Note:
· Be careful not to touch the LCD panel surface.
3.Use a hexagon head wrench, loosen the 3 screws fixing the
LCD panel attachment and screw them temporarily just until
the LCD panel attachment can be shifted by your fingers.
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4.Reassemble the projector in the reverse order of
disassembling, but leave the upper case and the screws
fixing the A-P.C.Board block as they are removed.
5.Adjust the convergence according to the section 9.4.
"Convergence Adjustment".
6.After the adjustment, screw the 2 screws (upper) fixing the
LCD panel attachment temporarily with care not to vary the
adjusting result.
Notes:
· Work carefully not to damage the flexible cable.
· Prepare a hexagon head wrench as shown in the
above figure.
7.Remove the LCD block again.
8.Tighten the 3 screws fixing the LCD panel attachment.
9.Reassemble the projector as it was.
8.12. LCD Panel Discrimination
ID-tag seal color LCD panel
Red LCD panel (R)
Blue LCD panel (B)
(No seal) LCD panel (G)
· Since the ID-tag seal is pasted to the FPC of LCD Panl, (R),
(G) or (B) can be easily identified by the color of the seal.
· Finally, identify the panel color by the part number printed
on the FPC.
8.13. LCD Panel Combination
· Part number is printed on the FPC of LCD Panel.
· When replacing LCD Panel, use a component which has
the same part number as the original.
LCD
panel Part No.
R L5BDAXQ00182
(L3P10X-55G00)
G L5BDAXQ00183
(L3P10X-55G00)
B L5BDAXQ00184
(L3P10X-55G00)
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