Audiovox LC17H2 User manual

LCD TELEVISION
FPE1705
(LC17H2)

CONTENTS
Safety instructions………………………………………………………………………..…
Adjustment instructions …………………………….…….…………………………….…
Trouble shooting ……………………………………………………….……………………
Method of software upgrading……………………………………………………….………
Working principle analysis…………………………………………. ………………………….
Block diagram…………………………………………………..……………………………
Main IC block diagram………………………………………………………………….……..
Wiring diagram ……………………………………………………………..……………....
Main assembly……………………………………………………………………………..…
Identification criteria for the bright spot and dark spot of the LCD screen………..….
Troubleshooting charts………………………………………………………………..……
Exploded view……………………………………………………………………..…........
1
2
6
7
9
10
11
16
17
17
18
21
Part list....................................................................................................................... 23
Schematic diagram..................................................................................................... 39

1
Safety instructions
1. Instructions
Be sure to switch off the power supply before replacing or welding any components or
inserting/plugging in connection wire Anti static measures to be taken (throughout the entire
production process!):
a) Do not touch here and there by hand at will;
b) Be sure to use anti static electric iron;
c) It’s a must for the welder to wear anti static gloves.
Please refer to the detailed list before replacing components that have special safety requirements.
Do not change the specs and type at will.
2. Points for attention in servicing of LCD
2.1 Screens are different from one model to another and therefore not interchangeable. Be sure to
use the screen of the original model for replacement.
2.2 The operation voltage of LCD screen is 700-825V. Be sure to take proper measures in
protecting yourself and the machine when testing the system in the course of normal operation or
right after the power is switched off. Please do not touch the circuit or the metal part of the module
that is in operation mode. Relevant operation is possible only one minute after the power is
switched off.
2.3 Do not use any adapter that is not identical with the TV set. Otherwise it will cause fire or
damage to the set.
2.4 Never operate the set or do any installation work in bad environment such as wet bathroom,
laundry, kitchen, or nearby fire source, heating equipment and devices or exposure to sunlight etc.
Otherwise bad effect will result.
2.5 If any foreign substance such as water, liquid, metal slices or other matters happens to fall into
the module, be sure to cut the power off immediately and do not move anything on the module lest it
should cause fire or electric shock due to contact with the high voltage or short circuit.
2.6 Should there be smoke, abnormal smell or sound from the module, please shut the power off at
once. Likewise, if the screen is not working after the power is on or in the course of operation, the
power must be cut off immediately and no more operation is allowed under the same condition.
2.7 Do not pull out or plug in the connection wire when the module is in operation or just after the
power is off because in this case relatively high voltage still remains in the capacitor of the driving
circuit. Please wait at least one minute before the pulling out or plugging in the connection wire.
2.8 When operating or installing LCD please don’t subject the LCD components to bending, twisting
or extrusion, collision lest mishap should result.
2.9 As most of the circuitry in LCD TV set is composed of CMOS integrated circuits, it’s necessary
to pay attention to anti statics. Before servicing LCD TV make sure to take anti static measure and
ensure full grounding for all the parts that have to be grounded.
2.10 There are lots of connection wires between parts behind the LCD screen. When servicing or
moving the set please take care not to touch or scratch them. Once they are damaged the screen
Attention: This service manual is only for service personnel to take reference with. Before
servicing please read the following points carefully.

2
would be unable to work and no way to get it repaired.
2.11 Special care must be taken in transporting or handling it. Exquisite shock vibration may lead to
breakage of screen glass or damage to driving circuit. Therefore it must be packed in a strong case
before the transportation or handling.
2.12 For the storage make sure to put it in a place where the environment can be controlled so as to
prevent the temperature and humidity from exceeding the limits as specified in the manual. For
prolonged storage, it is necessary to house it in an anti-moisture bag and put them altogether in one
place. The ambient conditions are tabulated as follows:
Temperature Scope for operation 0 ~ +50 oC
Scope for storage -20 ~ +60 oC
Humidity Scope for operation 20% ~ 85%
Scope for storage 10% ~ 90%
2.13 Display of a fixed picture for a long time may result in appearance of picture residue on the
screen, as commonly called “ghost shadow”. The extent of the residual picture varies with the
maker of LCD screen. This phenomenon doesn’t represent failure. This “ghost shadow” may remain
in the picture for a period of time (several minutes). But when operating it please avoid displaying
still picture in high brightness for a long time.
3. Points for attention during installation
3.1 The front panel of LCD screen is of glass. When installing it please make sure to put it in place.
3.2 For service or installation it’s necessary to use specified screw lest it should damage the screen.
3.3 Be sure to take anti dust measures. Any foreign substance that happens to fall down between
the screen and the glass will affect the receiving and viewing effect
3.4 When dismantling or mounting the protective partition plate that is used for anti vibration and
insulation please take care to keep it in intactness so as to avoid hidden trouble.
3.5 Be sure to protect the cabinet from damage or scratch during service, dismantling or mounting.
Adjusting instructions
1. Test equipment
Digital multimeter
5515 signal generator
K-7253 (VGA and YPrPb signal generator)
CA210 (LCD White balancer)

3
2. The alignment flow chart (see below figure)
Input YPrPb signal, check if the display is normal unde
r
PC and various functions (analog control, line/field
center etc.)
Check accessories and then packing
Check if N4, N20, N303 and N302 has
been FLASH written.
Produce main board and TV board
Check main board, TV board and power supply board
Check if output 12V and 18V of the power supply board is normal
Combined test for general assembly
Connect to central signal source, check if various TV functions (station
skipping, modulate quantity control etc) and the output of earphone
and speaker are normal
Input AV/S terminal signal, check
different functions of AV/S terminals
Testing TV board
Input VGA signal and check if display is normal in
the state of PC and various functions (analog
quantity control, line/field center etc.)
Input TV, S terminal and AV signals, check if AV
OUT is normal.

4
3. Flash writing programs
Flash writes memory N4, N20, N303 and N302.
4. Adjustment of power supply board
Connect the small power supply board to the power supply board (connect 12V of the small power
supply board to X905 of the power supply board, connect 18V of the small power supply board to
X906 of the power supply board), then turn on it, check if output is normal.
5. Adjustment of main board
a. Connect the main board X501 to infrared receiving board, connect X904 of the power supply
board to X1 of the main board, now the indication lamp of the infrared receiving board is red.
b. Connect PC, upgrade the program of FLASH N20, push the POWER key on the remote control
set. Now the indication lamp of the infrared receiving board is red.
c. About 4 minutes later the indication lamp of the infrared receiving board turns blue or yellow.
Measure L102 PIN2 to be 5.0 V, measure L107 PIN2 to be 3.3 V.
d. Flash write DDC program.
6. Adjustment of TV board
Connect main board, TV board and infrared receiving board and press the POWER button, now the
indication lamp of the infrared receiving board is blue or yellow. Measure N301 PIN2 of TV board to
be 3.3 V, one terminal of inductor L630 to be 5 V and one terminal of inductor L632 to be 12 V
7.Adjustment of white balance (using the white balancer CA210 and K7253 signal generator
specialized for LCD)
a. Install the whole TV set
b. Enter the factory menu and perform “PW1306 reset”
c. Exit from the factory menu. Press “ source” button and enter YPbPr.
d. Input YPbPr signal: 640x480p 60Hz (K7253).
e. Enter the user menu. Set the brightness to 50 and contrast to 50. Press “factory” button to enter
the factory menu, perform “ADC calibration”, input signals of “black field”(EMPT),”white field”(White-
(100%))”fully red”(Full_Magenta) respectively and then calibrate three times.
f. Input signal of “eight grade gray”(Gray (H)-8). Use CA-210 to measure the third grade and adjust
the brightness and contrast so that Y is around 180. Enter factory menu and adjust the green color
temperature and blue color temperature so that x=270,y=283(red color temperature is constant
as128).
g. Exit from the factory menu and enter RGB channel. Input 60Hz “pane signal ” (C_Hat_16x12(W))
through port VGA. Enter the user menu and adjust the brightness to 50 and contrast to 50. Adjust
the line center and the field center so that the picture is correctly positioned.
h. Input signal of “16 gray grades” (Gray(H)-16). Enter the factory menu and perform “calibration of
ADC”.
i. Exit from the factory menu, input the signal of “eight grade gray” (Gray(H)-8 ) and enter the user
menu. Adjust the brightness and contrast. Use CA-210 to measure the sixth grade so that Y is
around 180. Enter the factory menu and adjust the green color temperature and blue color
temperature so that x=284,y=299(red color temperature is constant as128).
j. Enter the factory menu and adjust the green color temperature and blue color temperature so that
x=284,y=299.
Notice: For the best discrimination rate of LCD screen, see table 1.
Table 1:LCD resolution of best

5
Screen size Factory LCD resolution of
best
Samsung
FUJITSU
LG
17”
PHILIPS
1280x1024
8.Performance check
a). TV Interfaces
Connect RF port to central signal source. Enter station search menu - auto station search. After
system adjustment is over, check if there is any station missing and then check semi-auto station
search.
Check if fine-tuning is normal.
Check if the output of earphone or loudspeaker is normal and if the picture is normal.
b). AV/S Terminals
Connect to access the signal of AV/S terminals separately and check if the picture or sound is
normal.
c). AV OUT Terminal
Input the signals separately in the status of TV/AV/S terminal. Connect AV OUT terminal to monitor
and check if the output picture and sound from AV OUT is normal. (Note: In the status of S terminal,
the output picture from AV OUT is colorless.)
d). VGA Interface
Input VGA signal (K7253 signal generator). Separately input the four types of VGA format signals as
listed in Table 2. Wait till auto calibration is over. Then check if the picture and sound is normal. If
there has been interference to the picture then press the auto set key on the remote control once
again and check if the display is normal.
Table 2.VGA format signal
screen size resolution Image clock(MHz) H-SYNC(kHz) V-SYNC(Hz) remark
640x480 @ 60 25.175 31.469 59.900
720x400 @ 70 28.322 31.469 70.086
800x600 @ 60 40.000 37.879 60.317
1024x768 @ 60 65.000 48.363 60.004
640x480 @ 70 31.500 37.861 70.000
800x600 @ 70 50.000 48.077 70.000
17”
1024x768 @ 70 75.000 56.476 70.000
e). YprPb Interface
Connect to access YprPb signal (K7253 signal generator). Separately input the five types of YprPb
format signals -- 480P/50 Hz, 480P/60 Hz, 720P/60 Hz, 1080I/50 Hz, 1080I/60 Hz and check if the
picture and sound is normal after auto calibration is over.
Connect to access YprPb signal (DVD signal generator). Input the signals -- 480I/50Hz, 480I/60 Hz
separately and check if the picture and sound is normal.
9. Preset ex-works
In the status of TV enter the factory menu by pushing the factory key and then perform presetting.
10. Ex-works packing
Check accessories and then pack them in box.

6
Trouble shooting
Before servicing please check to find the possible causes of the troubles according to the table
below.
1.Antenna (signal):
Picture is out of focus or jumping  Bad status in signal receiving
 Poor signal
 Check if there are failures with the electrical connector or
the antenna.
 Check if the antenna is properly connected.
Fringe in picture  Check if the antenna is correctly oriented.
 Maybe there is electric wave reflected from hilltop or
building.
Picture is interfered by stripe
shaped bright spots
 Possibly due to interference from automobile, train, high
voltage transmission line, neon lamp etc.
 Maybe there is interference between antenna and power
supply line. Please try to separate them in a longer
distance.
 Maybe the shielded-layer of signal wire is not connected
properly to the connector.
There appear streaks or light color
on the screen
 Check if interfered by other equipment and if interfered
possibly by the equipment like transmitting antenna,
non-professional radio station and cellular phone.
2.TV set:
Symptoms Possible cause
Unable to switch the power on  Check to see if the power plug has been inserted
properly into the socket.
No picture and sound  Check to see if the power supply of liquid crystal TV has
been switched on. (As can be indicated by the red LED
at the front of the TV set)
 See if it’s receiving the signal that is transmitted from
other source than the station
 Check if it’s connected to the wrong terminal or if the
input mode is correct.
 Check if the signal cable connection between video
frequency source and the liquid crystal TV set is correct.
Deterioration of color phase or
color tone
 Check if all the picture setups have been corrected.
Screen position or size is not
proper
 Check is the screen position and size is correctly set up.
Picture is twisted and deformed  Check to see if the picture-frame ratio is properly set up.
Picture color changed or colorless  Check the “Component” or “RGB” settings of the liquid
crystal TV set and make proper adjustment according to

7
the signal types.
Picture too bright and there is
distortion in the brightest area
 Check if the contrast setting is too high.
 Possibly the output quality of DVD broadcaster is set too
high.
 It maybe also due to improper terminal connection of the
video frequency signal in a certain position of the
system.
Picture is whitish or too bright in
the darkest area of the picture
 Check if the setting for the brightness is too high
 Possibly the brightness grade of DVD player
(broadcaster) is set too high.
No picture or signal produced from
the displayer if “XXX in search”
appears.
 Check if the cable is disconnected.
 Check if it’s connected to the proper terminal or if the
input mode is correct.
There appears an indication -
“outside the receivable scope)
 Check if the TV set can receive input signal. The signal is
not correctly identified and VGA format is beyond the
specified scope.
Remote control cannot work
properly
 Check if the batteries are installed in the reverse order.
 Check if the battery is effective.
 Check the distance or angle from the monitor.
 Check if there is any obstruct between the remote control
and the TV set.
 Check if the remote control signal- receiving window is
exposed to strong fluorescence.
No picture and sound, but only
hash.
 Check if the antenna cable is correctly connected, or if it
has received the video signal correctly.
Blur picture  Check if the antenna cable is correctly connected.
 Of if it has received the right video signal.
No sound  Check if the “mute” audio frequency setting is selected.
 Check if the sound volume is set to minimum.
 Make sure the earphone is not connected.
 Check if the cable connection is loose.
When playing VHS picture search
tape, there are lines at the top or
bottom of the picture.
 When being played or in pause VHS picture search tape
sometimes can’t provide stable picture, which may lead
to incorrect display of the liquid crystal TV, In this case
please press “auto” key on the remote control so as to
enable the liquid crystal TV set to recheck the signal and
then to display correct picture signal
Method of software upgrading
Steps of software upgrading are as follows:
1. Select a serial connection wire and a VGA connection wire and then connect them by means of a
patch panel;
2. Use a serial wire to connect the PC to the patch panel and set TV set to off state;

8
Open the software upgrade file holder and double click
FlashUpgraderNT (use under window 2000/XP/NT)
FlashUpgrader (use under window 98),
The following interfaces will show up after running the program:
Based on the computer features, set up the serial port (COM Port). Select corresponding serial port
(if it’s unable to FLASH WRITE, change to another port). Baud is selected to be 115200. Then
select Reset Target After Download. Click FLASH pushbutton, it’s ready to run. For other settings,
please refer to the Fig. Above (already defaulted by the system, normally no need to change).
Switch on TV set the FLASH write program begins to run;
After FLASH write is over, push button “cancel” will become flash. Then shut the main power supply

9
and it’s OK just switch it on again.
Note: Do not shut the power off or turn the TV set on during the FLASH write. Otherwise it
may lead to no way for flash to rewrite.
Working principle analysis
Multi-media liquid crystal TV broadcast and receiving set adopts liquid crystal display screen, which
is provided with NTSC color system receiving function in addition to AV input, S-VHS input, high
definition signal port for component YPrPb/YcbCr, PC VGA port, earphone output and other signal
ports. For power supply an externally connected power adaptor is provided.
The circuitry of LC20H8 is composed of RF module board, video signal board, digital signal picture
processor and AC-DC transformer, and DC-DC circuit board.
The working process is as follows. The radio frequency signal undergoes an integrated tuner
TUNER1 before a color full video signal is generated. This video signal then enters analog board
decoder IC N303 VCT3833 Pin19 where it is processed and it’s output as analog signals R, G, B
through Pin42, PIN43, and PIN44. Audio frequency signal is processed with sound in IC N401
MSP3420G and then output through MSP3420G Pin28, Pin27 to SRS for surround sound
processing in IC N403 M62494E. Finally it is subject to power amplification in IC N404 TDA1517
before it is output to speaker.
VGA signal/high definition signal is input to personal computer through the main board. The signal
selected by Y/Pb/Pr through 5 way 1/2 switches IC(N1 BA7657F)is subject to reselection together
with signal TVRAIN, TVGAIN, TVBAIN through 5 way 1/2 switches IC(N5 BA7657F). Finally signals
R, G, B are selected and sent to the main processing chip IC N19 PW1306.
IC N19 PW1306 is a built-in X86 CPU of the main processing IC, externally connected by 8M Flash
(N20) memory to control the whole system. The input signal of V-port and G-port is subject to
internal arithmetic processing and then output as R, G, B signals with electric level of 24 bit TTL to
sockets JP3 and JP4, where through connection wires the signals are sent to the port of LG liquid
crystal screen and for the realization of picture reproduction.

10
Block diagram

11
Main IC block diagram
1.TPA1517
2.DS90C383A/DS90CF383A

12
3.VCT 38xx A/B
Video
Front-end Comb
Filter Color
Decoder
Display
Processor Video
Back-end
Panorama
Scaler
43
4
12
31
2
2
ICMaster
3kB
OSD
96 kB
CPU ROM
TPU DMA CPU
24 IO Ports
Watchdog
2 CapCom
2 Timer
15:1 Mux
10-bit ADC
8-bit PWM
Audio
3
2
Clock
Oscillator
1kB
CPU RAM
XTAL1
XTAL2
VIN
AIN
ADB, DB, CB
RGBOUT
RGBIN
VERT PROT HFLB SENSE
IC
2
XREF
HOUT
VRD
VRT
SGND
Color, Prio
MSync
IC
2
VSUPAB
VSUPP1
GNDP1
Reset
Logic
RESQ
VSUPS
TEST
GNDAB
VSUPAF
VSUPD
GNDAF
GNDD
RSW
2
GNDM
EW
8
14-bit PWM
2 2
3
CIN SVM
Video
GNDS
CLK20
RDY
BE
24 kB
VCT 38xxA/B
AOUT
VSync
VOUT
24 kB ROM
3kB
OSD RAM
Pict.Improv
16 kB
Te xt
RAM

13
4.MSP 34x0G

14
5.BA7657F / BA7657S
1
2
3
4
5
6
7
8
9
10
11
12
24
23
22
21
20
19
18
17
16
15
14
13
1
2
1
2
1
2
1
2
12
DET
Logic
Syncsepa
Ground
Ground
Ground
Ground
V
CC
CTL (H:IN1, L: IN2)
Red 1 input
Green 1 input
Blue 1 input
Red 2 input
Green 2 input
Blue 2 input
VD 1 input VD 2 input
VD output
Blue output
Composite sync output
Composite video input (Sync on Green)
Green output
Red output
HD output
HD 2 input
HD 1 input
HD Sync signal detector

15
6.PW1306
A/DClamp
DERGB (23:0) DORGB(23:0) DVS, DHS, DEN, DCLK
NMI
Interrupt
Controller
RxDTxD
UART
Watchdog and
Timers
Processor ROM/
RAM Interface
16-Bit
Microprocessor
PortA & D (7:0)
GPIO PWM IR
Decoder
A
(19:1) D
(15:0) CS
(1:0)
2-Wire
Serial
Microprocessor Bus
Memory Out Bus
Memory
Buffer
Processor
Memory
Interface
Memory In Bus
OSD
PW1306 Video ImageProcessor
Internal Block Diagram
ADC
Sync
Processing
HSHSYNC,
VSYNC SOY
Stripper
SOYIN
FILT PLL CLK
R/Pr
G/Y
B/Pb
A/DClamp A/DClamp
VS
PowerOn
Reset
RESET Reset
XI XO
PLL and
Oscillator
MCLK DCLK UCLK
Scaling &
Video
Enhancement
Color
Matrix
OSD
and
Gain
Color
Lookup
Tables
Display
Timing
Generator
Color
Space
Expander
CSC Auto
Image

16
Wiring diagram

17
Main assembly
301-UL20H3-31R Remote control (RC-U31R)
615-10448-00 Stand
615-20359-00 Speaker
667-L15H3-55A H-frequency board
667- L17H2-01 Main board
667- L17H2-05 Button board
667- L17H2-09 IR receiving board
667- L17H2S-14 Backlight board
667- L17H2-20 Power supply board
Identification criteria for the bright spot and dark spot of the LCD screen
Quantity allowed Distance between two spotsCatego
ry Criteria 15" 20" 22" 30" 40" 15" 20" 22" 30" 40"
One single spot ≤5 ≤2 ≤5 ≤2 ≤3
Two neighboring
spots
≤2 ≤1 ≤2 ≤1 ≤1
Bright
spot
Total No. ≤5 ≤2 ≤5 ≤2 ≤3
≥15mm
One single spot ≤6 ≤7 ≤5 ≤4 ≤10
Two neighboring
spots
≤2 ≤2 ≤2 ≤1 ≤5
Dark
spots
Total No. ≤6 ≤7 ≤5 ≤4 ≤10
≥15mm
≥10mm ≥5mm
Total defected point ≤8 ≤7 ≤5 ≤4 /
Notes:
1. Definition of defected point (bright spot, dark spot): It is identified as a defected point if its area
exceeds 1/2 of a single picture element (R, G, B).
2. Definition of bright spot: It is identified as a bright spot if it is bright in the state of dark field and its
bright size remains unchanged
3. Definition of dark spot: It is identified as a dark spot if it is dark in the state of white field and its
dark size remains unchanged
4. Definition of two neighboring points: Defects of a group of picture elements (RB, RG, GB).

18
Troubleshooting charts
1. No raster, no picture and no sound
Display LOGO? Check input 12V and 18V of digital
board
Check if output H-
V
sync of R, G, B fo
r
X601 of TV board.
Connect X1 of the digital
board to X904 of the powe
r
supply board is normal?
Replace high
frequency board
Check if output 12V and
18V of X904 of powe
r
supply board
Replace power suppl
y
board
Check if output 5V o
f
U1 (AP1501-50K5)
Replace digital
board
Check if pin7of N4 is
high level
Check if output 5V o
f
5V-STB is normal
Replace IC (N4)
Replace D102
Check if pin SD o
f
U1 is low level
Replace U1
Replace V102
Y
N N
Y Y
N
Y
N
Y
Low
High
Y
N
N
N