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Service Manual
ViewSonic N2750w-1(M)
Model No. VS10576-1M
27" LCD TV
(N2750w-1M_SM Rev. 1a Apr. 2006)
ViewSonic® 381 Brea Canyon Road, Walnut, California 91789 USA - (800) 888-8583
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.
Disclaimer
ViewSonic makes no representations or warranties, either expressed or implied, with respect to the contents
hereof and specifically disclaims any warranty of merchantability or fitness for any particular purpose. Further,
ViewSonic reserves the right to revise this publication and to make changes from time to time in the contents
hereof without obligation of ViewSonic to notify any person of such revision or changes.
Trademarks
Optiquest is a registered trademark of ViewSonic Corporation.
ViewSonic is a registered trademark of ViewSonic Corporation.
All other trademarks used within this document are the property of their respective owners.
Revision History
Revision SM Editing Date ECR Number Description of Changes Editor
1a 04/04/06 Initial Release Sophia Kao
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ViewSonic Corporation Confidential - Do Not Copy N2750w-1
TABLE OF CONTENTS
1. Precautions and Notices ......................................................................3
2. Service Tool & Equipment Required.....................................................4
3. Specifications........................................................................................4
4. Exploded View and Parts List................................................................8
5. Block Diagram.......................................................................................10
6. Schematic Diagrams.............................................................................11
7. Working Theorem................................................................................. 25
8. Wiring Diagram..................................................................................... 27
9. PCB Layout Diagrams.......................................................................... 28
10. Trouble Shooting Flow Chart.............................................................. 36
11. Adjustment.......................................................................................... 40
12. Recommended Spare Parts List......................................................... 42
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ViewSonic Corporation Confidential - Do Not Copy N2750w-1
1. Precautions and Notices
1.1. SAFETY PRECAUTIONS
This LCD TV is manufactured and tested on a ground principle that a user's safety comes first.
However, improper use or installation may cause damage to the LCD TV as well as to the user.
Carefully go over the following WARNINGS before installing and keep this guide handy.
WARNINGS:
! This LCD TV should be operated only at the correct power sources indicated on the label on
the rear end of the LCD TV. If you're unsure of the power supply in your residence, consult
your local dealer or power company.
! Use only the special power adapter that comes with this LCD TV for power input.
! Do not try to repair the LCD TV yourself as it contains no user-serviceable parts. This
LCDTV should only be repaired by a qualified technician.
! Do not remove the LCD TV cabinet. There is high-voltage parts inside that may cause
electric shock to human bodies, even when the power cord is unplugged.
! Stop using the LCD TV if the cabinet is damaged. Have it checked by a service technacian.
! Put your LCD TV only in a clean, dry environment. If it gets wet, unplug the power cable
immediately and consult your service technician.
! Always unplug the LCD TV before cleaning it. Clean the cabinet with a clean, dry cloth.
Apply non-ammonia based cleaner onto the cloth, not directly onto the glass screen.
! Keep the LCD TV away from magnetic objects, motors, TV sets, and transformer.
! Do not place heavy objects on the LCD TV or power cord.
1.2. PRODUCT SAFETY NOTICE
Many electrical and mechanical parts in this chassis have special safety visual inspections and the
protection afforded by them cannot necessarily be obtained by using replacement components
rated for higher voltages, wattage, etc. Before replacing any of these components read the parts
list in this manual carefully. The use of substitute replacement parts which do not have the same
safety characteristics as specified in the parts list may create shock, fire, or other hazards.
1.3. SERVICE NOTES
1. When replacing parts or circuit boards, clamp the lead wires around terminals before
soldering.
2. When replacing a high wattage resistor (more than 1W of metal oxide film resistor) in circuit
board, keep the resistor about 5mm away from circuit board.
3. Keep wires away from high voltage, high temperature components and sharp edges.
4. Keep wires in their original position so as to reduce interference.
5. Usage of this product please refer to also user's manual.
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2. Service Tool & Equipment Required
1. SIGNAL GEN.
2. MULTIMETER
3. OSCILLOSCOPE
4. SCREW DRIVER
5. IRON
6. ABSORBER
7. SOLDER
8. DUMMY LOAD (5/200W)
9. DVD PLAYER
3. Specifications
3.1. PRODUCT SPECIFICATIONS
LCD Panel 27" TFT
Power Management < 5W
(OFF MODE)
Displayable Resolution VESA 1366 x 768 max.
Pixel Dimension 0.4365(H)×0.4365(W)mm
LCD Display Color 16.7M Color Max. (8bit/color)
Viewing Angle CR10
Horizontal: -85°+85°
Vertical: -85°+85°
Contrast Ratio 1000 : 1 (typical)
Brightness 550 cd/m2 (typical)
Response Time 8ms (typical ,gray to gray )
Active Display Area 596.259mm×335.232mm
RF Tuner Input level: 0 ~ +15 dB mV
Rang: NTSC 55.25 to 801.25 MHz, 2-69 channels for Off-Air
and 2-125 Channeis for CATV
Power Voltage: 100~240 V
Consumption:150 Watts(Max.)
Speaker 10W×2
Compliance FCC,UL
Temperature Operating : 0°C~ +40°C
Storage : -20°C~+60°C
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3.2. FACTORY SUPPORTING MODES
ITEM 1 2 3 4
TIMING 640× 480 60HZ 640× 480 67HZ 640× 480 75HZ 720× 400 70HZ
Pixel Rate 25.175MHZ 30.240MHZ 31.500MHZ 28.322MHZ
H TOTAL 31.778us 28.571us 26.667us 31.778us
H DISPLAY 25.422us 21.164us 20.317us 25.422us
H B-Porch 1.907us 3.175us 3.810us 1.907us
H Width 3.813us 2.116us 2.032us 3.813us
H Border 0.318us 0.000us 0.000us 0.318us
V TOTAL 16.683ms 15.000ms 13.334ms 14.268ms
V DISPLAY 15.253ms 13.714ms 12.800ms 12.710ms
V B-Porch 1.049ms 1.114ms 0.427ms 1.111ms
Vs Width 0.064ms 0.086ms 0.080ms 0.064ms
V Border 0.254ms 0.000ms 0.000ms 0.254ms
H/V Sync -/- -/- -/- -/+
Interlace No. No. No. No.
ITEM 5 6 7 8
TIMING 800× 600 56HZ 800× 600 60HZ 800× 600 72HZ 800× 600 75HZ
Pixel Rate 36.000MHZ 40.000MHZ 50.000MHZ 49.500MHZ
H TOTAL 28.444us 26.400us 20.800us 21.333us
H DISPLAY 22.222us 20.000us 16.000us 16.162us
H B-Porch 3.556us 2.200us 1.280us 3.232us
H Width 2.000us 3.200us 2.400us 1.616us
H Border 0.000us 0.000us 0.000us 0.000us
V TOTAL 17.778ms 16.579ms 13.853ms 13.333ms
V DISPLAY 17.066ms 15.840ms 12.480ms 12.800ms
V B-Porch 0.626ms 0.607ms 0.478ms 0.448ms
Vs Width 0.057ms 0.106ms 0.125ms 0.064ms
V Border 0.000ms 0.000ms 0.000ms 0.000ms
H/V Sync +/+ +/+ +/+ +/+
Interlace No. No. No. No.
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ITEM 9 10 11 12
TIMING 832× 624 74.5HZ 1024× 768 60HZ 1024× 768 70HZ 1024× 768 75HZ
Pixel Rate 57.280MHZ 65.000MHZ 75.000MHZ 78.750MHZ
H TOTAL 20.111us 20.677us 17.707us 16.660us
H DISPLAY 14.525us 15.754us 13.653us 13.003us
H B-Porch 3.910us 2.462us 1.920us 2.235us
H Width 1.117us 2.092us 1.813us 1.219us
H Border 0.000us 0.000us 0.000us 0.000us
V TOTAL 13.417ms 16.666ms 14.272ms 13.328ms
V DISPLAY 12.549ms 15.880ms 13.599ms 12.795ms
V B-Porch 0.784ms 0.600ms 0.513ms 0.466ms
Vs Width 0.060ms 0.124ms 0.106ms 0.050ms
V Border 0.00ms 0.000ms 0.000ms 0.000ms
H/V Sync -/- -/- -/- +/+
Interlace No. No. No. No.
ITEM 13
TIMING 1280 × 1024 60HZ
Pixel Rate 108MHZ
H TOTAL 15.630us
H DISPLAY 11.852us
H B-Porch 2.296us
H Width 1.037us
H Border 0.000us
V TOTAL 16.661ms
V DISPLAY 16.005ms
V B-Porch 0.594ms
Vs Width 0.047ms
V Border 0.00ms
H/V Sync +/+
Interlace No.
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3.3. D-SUB CONNECTOR
Connector pin assignments for VGA cable
The signal cable connector shall be a molded-over, shield twisted pair cable. The cable shall be
1.8 meters long. The pin assignments shall be listed as below:
PIN D-SUB Connector
1 Red Video
2 Green Video
3 Blue Video
4 NC
5 GND
6 GNC
7 GND
8 GND
9 +5V for DDC
10 GND
11 NC
12 SDA
13 H-sync
14 V-sync
15 SCL
Connector pin assignments for DVI cable
DVI: 24 pins DVI connector is designed to match with DVI-D digital signal cable, the pin
assignment is as the following:
Pin Signal Assignment Pin Signal Assignment Pin Signal Assignment
1 TMDS RX2- 9 TMDS RX1- 17 TMDS RX0-
2 TMDS RX2+ 10 TMDS RX1+ 18 TMDS RX0+
3 TMDS Ground 11 TMDS Ground 19 TMDS Ground
4 Floating 12 Floating 20 Floating
5 Floating 13 Floating 21 Floating
6 DDC Clock 14 +5V Power 22 TMDS Ground
7 DDC Data 15 Ground 23 TMDS Clock+
8 Floating 16 Hot Plug Detect 24 TMDS Clock-
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4. Exploded View and Parts List
FIG.1 1F26
KEYPAD PCB ASS'Y
1F27 1F29 X2 POWER PCB ASS'Y
1F01 1F36
1F28 X2
1F12 X4
1F10
AUDIO PCB ASS'Y
1F23 X4
1F38
1F30
1F12 X4
1F19
1F12 X6
1F29 X2
V901
1F12
1F06 X4
1F11 X3 1F18 X3
1F11 X2
1F16 X3
1F05
IR PCB ASS'Y
MAIN PCB ASS'Y 1F31 X10
1F15
1F17 1F33
1F13 1F32 X2
1F21 X2
1F25 1F14 X3
1F21 X4
1F23 X4
1F25
2C01
1F24 X6
1F11 X2
1F21 X2
FIG.1 1F11 X3
NOTE.1 1F22
1F39 X3
5B01
1F25
2C03
1F25
1F25 2C04
5B03 X4
1F25 2C05
1F25 1F25
5B02X6
2C06X2
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ViewSonic Corporation Confidential - Do Not Copy N2750w-1
EXPLODED PARTS LIST (N2750w)
ViewSonic Model Number: VS10576-1M
Rev: 1a
Serial No. Prefix: PJL
Item ViewSonic P/N Ref. P/N Description Q'ty
1F01 C-00001791 2603307683 BEZEL ASS'Y JC278 ABS 94V0 BLACK #4001 1 1
1F05 N/A 2044266501 FUNCTION KEY JC278 ABS 94V0 AL-PLATE POWER 1 1
1F06 M-SCW-0824-0285 2084730082 SCREW,BND T+ M3X8(BND T+) 4 4
1F10 N/A 2071971300 METAL FITTG JC278 SECC t=1.0mm FOR PANEL 1 1
1F11 N/A 2080005200 SCREW,SPE M3*3 TYPE I FOR HS PANEL NI 10 10
1F12 M-SCW-0824-0811 2080003700 SCREW,SPE 1SZZTER001A M3*6LMSWR17/FZMY1 14 14
1F13 N/A 2072050400 METAL FITTG-I/O JC278 SECC t=1.0mm IO MAIN(U) 1 1
1F14 N/A 2083730108 SCREW,BND T+ M3X10,T24,F,NI 3 3
1F15 N/A 2072050500 METAL FITTG-I/O JC278 SECC t=1.0mm IO SIDE(U) 1 1
1F16 N/A 2082340102 SCREW,CSK+ SCREW F M4X10 (CSK+) 3 3
1F17 N/A 2027259402 DUST COVER JC278 ABS 94HB BLACK #4001 1 1
1F18 N/A 2083730108 SCREW,BND T+ M3X10,T24,F,NI 3 3
1F19 N/A 2071971400 METAL FITTG JC278 SECC t=1.0mm FOR SPK 1 1
1F21 M-SCW-0824-0285 2084730082 SCREW,BND T+ M3X8(BND T+) 8 8
1F22 N/A 2071870300 BRACKET,FIX JC278 Aluminum 1 1
1F23 N/A 2082740122 SCREW,BND+ M4X12 (BND+) 8 8
1F24 N/A 2082340102 SCREW,CSK+ SCREW F M4X10 (CSK+) 6 6
1F25 M-SCW-0824-0811 2080003700 SCREW,SPE 1SZZTER001A M3*6LMSWR17/FZMY1 8 8
1F26 N/A 2027259002 DUST COVER JC278 ABS 94HB BLACK #4001 1 1
1F27 N/A 2044266601 FUNCTION KEY JC278 ABS 94V0 AL-PLATE FUNCTI 1 1
1F28 M-SCW-0824-0285 2084730082 SCREW,BND T+ M3X8(BND T+) 2 2
1F29 M-SCW-0824-0811 2080003700 SCREW,SPE 1SZZTER001A M3*6LMSWR17/FZMY1 11 11
1F30 N/A 2071671000 SHIELD PLATE JC278 SECC t=1.0mm 1 1
1F31 N/A 2082340102 SCREW,CSK+ SCREW F M4X10 (CSK+) 10 10
1F32 N/A 2083630068 SCREW FMS+ M3X6,M,S-TITE,F,NI 2 2
1F33 N/A 2080040062 SCREW,SPE M4*8 PMS-3/W 1 1
1F36 N/A 2072459100 INSULATOR PC FR700 180X130 SONY T4000 1 1
1F38 N/A 2071871100 BRACKET,FIX JC278 SECC T=0.8mm FOR SWITCH 1 1
1F39 M-SCW-0824-0811 2080003700 SCREW,SPE 1SZZTER001A M3*6LMSWR17/FZMY1 3 3
2C01 C-00001790 2022262602 CABI BACK JC278 ABS 94HB BLACK #4001 1 1
2C03 N/A 2027259202 DUST COVER JC278 ABS 94HB BLACK #4001 1 1
2C04 N/A 2027259302 DUST COVER JC278 ABS 94HB BLACK #4001 1 1
2C05 N/A 2027259102 DUST COVER JC278 ABS 94HB BLACK #4001 1 1
2C06 N/A 2082740122 SCREW,BND+ M4X12 (BND+) 2 2
5B01 C-00001876 2071870401 BRACKET,FIX JC278 BASE ALUMINUM BLACK 4001 1 1
5B02 PL-PD-0714-0069 2039802303 FOOT PAD VA520 CR420x 16.5x5.8 BLACK 6 6
5B03 N/A 2082750402 SCREW,BND+ M5X40,M,P,ZN-CC 4 4
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5. Block Diagram
ANT TV Tuner TV Sound Audio Amp
Processor
Philips FQ1236/F H-3 L+R YAMAHA YDA135 L+R
Micronas MSP3445/
MSP3425
Audio Out
Earphone Amp EARPHONE
TI TPA6110A2
PC Audio In
YPbPr Audio In MUX
AV Audio In
HEF 4052BT
SDRAM
1Mx16 SDRAM
M12L16161A 2Mx32x3
K4S643232H
TV Video Decoder
AV Trumpion
S-video T0956 CCIR656
YCbCr W/3D-COM,C.C&V-CHIP
A port
Scaler
DVI+HDCP interface w/ de-interlace
SiI169 LVDS Tx To Panel
trumpion
VGA input Video SW p.HD (t0932)
YPbPr TS5V330/ADG774 ADC RGB 24bits B port
AD9883KST
To INVERTER +24V
I2C Control POWER
SUPPLY To main board +12V
IR Receiver MCU
128K
STK6012
Keypad Control +5V
+12V +5V
DC to DC +3.3V
EEPROM +2.5V
24C16
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6. Schematic Diagrams
6.1 DC-Power
+12VIN
P126 L1813.5X9X0.8
4 +12V +12VIN
3 L182 3.5X9X0.8 L107 I103
2 CHOKE SAKEN/8050SD VCCV
1
1 VIN FEEDBACK 4
L108 40uH
4 HEADER P
100n C114
5 ON/OFF OUTPUT 2
100n C116
GND
2
C113
NC
+12VIN R102 D103
P101 NC/0R MS22 C115
3
ION_OFF R509 0R
10 IADJ
1
9
8 L101 I101 P 1500uF/10VLESR
7 CHOKE SAKEN/8050SD VCC R103
6
5 1 VIN FEEDBACK 4 11 SYS_PD
L104 40uH
4
100n C105
3 5 ON/OFF OUTPUT 2
NC/0R
100n C107
GND
2
2
C101 L106
1 VCC
1000uF/16V BEAD/80R
R101 D101
CON10 NC/0R MS22 C106 VCCV R105
3
R104 2K2 Q101
1
2
3
10K FDS9435
1
100n C110
P 1500uF/10VLESR R106 4 4
VCC C574 10K
330p R107 Vpnl
8
7
6
5
2K2 2
VCCV 1 Q102
3 MMBT3904
2
R108 4K7 1
11 PANELPWR
Q103 3 R109
R111 MMBT3904 150R/0805
VCC=+5V C111 C112
4K7 100n 47uF/16V
VCCV I104 +3V3 Q104
LM1084/3V3/TO263 MMBT3904 2
3 2 R114 4K7 IADJ R110 4K7 1
VI VO
ADJ
3
R115 4K7 2
1 Q105
8 PHDPWM0
R116 NC C117
1
3
C118 MMBT3904 330p
47uF/16V
R117
0R C119
220uF/16V R118 NC
VCCV
VCC +3V3
+2V5 +2V5
R121
4K7
R272 R122 Q106
10K Q113 4K7 ION_OFF
1
2
3
R123
AP9620M R274 R124 MMBT3904
NC 10K 2
VCC +3V3 VCC +3V3 R273 4K7 4 4 1
11 BACKLITn
3 C121
NC
8
7
6
5
NC
2
R269 R270 R271 4K7 1 Q112
TVM_PWRp
NC NC 11 3 MMBT3904 +2V5S
R268
10K
Q111
1 S1 D1 8
R275 4K7 2 7
G1 D1 +3V3S
3 S2 D2 6
4 G2 D2 5 +5VS
2
R267 4K7 1 Q110
TVM_PWRp
11 3 MMBT3904 SI9933ADY
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6.2 DVI
I105
SII169
RX0+ 90 77
RX0- RX0+ QO23
91 RX0- QO22 75
ODD RED
RX1+ 85 74
RX1- RX1+ QO21
86 RX1- QO20 73
RX2+ 80 72
RX2- RX2+ QO19
81 RX2- QO18 71
RXC+ 93 70
VDDCD RXC- RXC+ QO17
94 RXC- QO16 69
R125 510R 96 66
L109 EXT_RES QO15