Sharp SX76NF8 Service Manual
SERVICE MANUAL
S13V5SX76NF8/
COLOUR TELEVISION
Chassis No. GA-20X
SX76NF8
MODEL
In the interests of user-safety (Required by safety regulations in some countries) the set should be restored
to its original condition and only parts identical to those specified should be used.
SX76NF8
FEATURE
Ë
Ë
Full Auto Channel Preset and Auto Channel Skip
Ë
100 CH Program Memory
Ë
CATV (Hyper Band) Ready
<Used Frequency Synthesizer Tuner>
Ë
High Contrast Picture
Ë
TELETEXT(10 page)
English / German / French / Spanish / Italian
/ Swedish / Dutch / portuguese
Ë
ON Timer/OFF T imer
Blue Back Noise Mute
Ë
White Temperature Adjustment
Ë
Child Lock
Ë
Auto Sound Limiter
Ë
Headphone Terminal
Ë
Stereo (NICAM / IGR) Decoder
Ë
Rotation adjustment (picture tilt adjustment)
Ë
Component Input Terminal
CONTENTS
Page
» SPECIFICATIONS.............................................2
» IMPORTANT SERVICE NOTES........................2
» ADJUSTMENT PRECAUTIONS........................3
» TROUBLE SHOOTING TABLE ......................... 8
» WAVEFORMS ..................................................12
» CHASSIS LAYOUT ..........................................14
» BLOCK DIAGRAM...........................................16
» DESCRIPTION OF SCHEMATIC DIAGRAM ..18
» SCHEMATIC DIAGRAM
Ë
CRT UNIT.....................................................19
Ë
MAIN UNIT ...................................................20
Ë
CONTROL UNIT .......................................... 26
Ë
DF UNIT .......................................................28
Ë
LED UNIT .....................................................29
Ë
KEY UNIT..................................................... 29
Ë
SUB WOOFER UNIT ...................................30
» PRINTED WIRING BOARD ASSEMBLIES..... 31
» REPLACEMENT PARTS LIST
Ë
ELECTRICAL PARTS
MAIN UNIT ................................................... 38
CRT UNIT.....................................................43
CONTROL UNIT .......................................... 44
DF UNIT .......................................................45
LED UNIT .....................................................45
SUB WOOFER UNIT ...................................45
KEY UNIT..................................................... 45
Ë
MISCELLANEOUS PARTS..........................46
Ë
SUPPLIED ACCESSORIES.........................46
Ë
PACKING PARTS......................................... 46
Ë
CABINET PARTS ......................................... 46
Ë
CABINET PARTS LOCATION...................... 46
» PACKING OF THE SET...................................47
Page
The chassis in this receiver is partially hot. Use an isolation transformer between the line cord plug and power
receptacle, when servicing this chassis. To prevent electric shock, do not remove cover. No user – serviceable
parts inside. Refer servicing to qualified service personnel.
WARNING
SHARP CORPORATION
1
SX76NF8
SPECIFICATIONS
Convergence ................................................................. Self Convergence System
Focus ............................................................Electrostatic Focus High Bi-Potential
Sweep Deflection......................................................................................Magnetic
Intermediate Frequencies
Picture IF Carrier .................................................................................. 38.9MHz
Sound IF Carrier Frequency
5.5MHz ..............................................................................................33.4MHz
Colour Sub-Carrier Frequency............................................................34.47MHz
Power Input......................................................................... AC 220 ~ 240V 50 Hz
Power Consumption ...................................................................................... 140W
Audio Power Output Rating ............................................5W + 5W + 10W(at Max.)
Speaker
Size.............................................................................. 11 x 5 cm Elliptic (2 pcs)
10cm Round (1pc)
Voice Coil Impedance..............................................................4 ohm (11 x 5cm)
8 ohm (10cm)
Aerial Input Impedance
VHF/UHF ............................................................................ 75 ohm Unbalanced
Receiving System (PAL-B/G)
VHF.......................................................................................AU 0 thru AU 12 ch
UHF ....................................................................................AU 28 thru AU 69 ch
Receiving Frequency
VHF-Channels ......................................................... 44.25MHz thru 463.25MHz
UHF-Channels....................................................... 471.25MHz thru 863.25MHz
Dimensions................................................................................... Width: 880.0mm
Height: 566.0mm
Depth: 545.0mm
Weight(approx): 54.0 kg
Cabinet material .................................................................................... All Plastics
Specifications are subject to change without prior notice.
IMPORTANT SERVICE NOTES
Maintenance and repairing of this receiver should be done by quali-
fied service personnel only .
SERVICE OF HIGH VOLTAGE SYSTEM AND PIC-
TURE TUBE
When servicing the high voltage system, remove static charge from it by
Connecting a 10K ohm Resistor in series with an insulated wire(such as a
test probe) between picture tube dag and 2nd anode lead. (AC line cord
should be disconnected from AC outlet.)
1. Picture tube in this receiver employs integral implosion protection.
2. Replace with tube of the same type number for continued safety.
3. Do not lift picture tube by the neck.
4. Handle the picture tube only when wearing shatterproof goggles and after discharging
the high voltage completely.
X-RAY
This receiver is designed so that any X-Ray radiation is kept to an absolute
Minimum. Since certain malfunctions or servicing may produce potentially
hazardous radiation with prolonged exposure at close range, the following
precautions should be observed:
1. When repairing the circuit, be sure not to increase the high voltage to more than 34.5kV(at
beam 0
µ
A) for the set.
2. To keep the set in a normal opeartion , be sure to make it function on 30.5kV
±
1.5kV(at
beam 1800
µ
A) in the case of the set. The set has been factory - Adjusted to the above-
mentioned high voltage.
*If there is a possibility that the high voltage fluctuates as a result of the repairing,
never forget to check for such high voltage after the work.
3. Do not substitute a picture tube with unauthorizerd types and/or brands which may
cause excess X-ray radiation.
BEFORE RETURNING THE RECEIVER
Before returning the receiver to the user, perform the following safety Checks.
1. Inspect all lead dress to make certain that leads are not pinched or that hardware is not
lodged between the chassis and other metal parts in the receiver.
2. Inspect all protective devices such as non-metallic control knobs, insulating fishpapers,
cabinet backs, adjustment and compartment covers or shields, isolation resistor- ca-
pacity networks, mechanical insulators etc.
2-2
2-1
2
SX76NF8
ADJUSTMENT PRECAUTIONS
All adjustments to this chassis, except for focus, are carried out in the Service Mode.
Service Mode
The Service Mode is provided to enable the engineer to correctly set up the receiver to the CRT fitted in the set.
Note that these adjustments may vary from one receiver to another.
To enter the Service Mode, carry out the following procedure.
1.Connect a test pattern to the antenna terminal.
2.Tune the receiver to this signal.
3.Turn the receiver off using the mains switch.
4.Press volume down and channel up buttons on the front of
the receiver at the same time.
5.Keeping these buttons pressed, turn the mains on.
6.When the set starts up it will be in Service Mode.
7.Release the two buttons.
» Use the channel up and down buttons to move between the options.
» Use the volume control buttons to change the data.
» To store the data, use the stand-by button on the remote control.
» To exit the Service Mode, turn the receiver off using the mains switch.
When the Service Mode is entered the following On Screen Display appears
SERVICE SOFTWARE
SW on: XXXX SW off: XXXX Hours ON: XXXX
The figures displayed in the XXXX locations are hexadecimal representations of the number of times that particular
function has been executed. For example if the hexadecimal number displayed after SW ON was 0E4A, this would
correspond to the receiver being turned on 3658 times.
Adjustment menu:
The following adjustments can be carried out in the Service Mode.
» Horizontal Shift » Blue Gain
» East West Width » Red Cut Off
» Pin Phase » Green Cut Off
» Pin Amp (Amplitude) » Blue Cut Off
» Corner Amplitude » Alter NVM Pag (Page)
» Corner Symmetry » Alter NVM Pos (Position)
» Vertical Linearity » Alter NVM Val (Value)
» Vertical Angle » Teletext Mix Mode Contrast
» Vertical Bow » Teletext Contrast
» Vertical Amplitude » OSD Contrast
» S Correction » DVCO Adjustment (Only PAL)
» Vertical Shift » DVCO Adjustment (Only NTSC)
» Red Gain » AGC Adjustment
» Green Gain » Rotation Inspection
» INTIAL On/Off
Note that the receiver should be set to FULL MODE before carrying out any geometry adjustments. This can be achieved
by pressing the widescreen mode button on the remote control until FULL MODE appears on the OSD. This can only be
done out of the Service Mode.
Detailed instructions on how to execute these are given on the following pages.
Front
Top of front cabinet
Changing NVM Data
To change the data contained within the Non Volatile Memory, it is necessary to first select the page the data is stored
in, then the position and finally to change the data itself. The procedure below outline this process.
1. Press the channel up/down buttons and ALTER NVM PAG appears, use the volume up/down buttons to change this
data (it is shown in hexadecimal format).
2. Press the channel up button and ALTER NVM POS appears use the volume up/down buttons to change this data (it
is shown in hexadecimal format).
3. Press the channel up button and ALTER NVM VAL appears, use the volume up/down buttons to change this data (it
is shown in hexadecimal format).
4. Once this data has been set, press the stand-by button to store.
5. If another NVM value has to be changed, use the channel down button to select the page or position and repeat as
necessary.
Note: DO NOT change any NVM data, unless you have been adviced to do so by a Sharp representative. If data is
incorrectly changed, serious damage may occur to hte receiver.
3-2
3
3-1
SX76NF8
PIF ADJUSTMENT
NO
1
ADJUSTMENT POINT
RF-AGC
ADJUSTMENT
(I2C BUS CONTROL)
ADJUSTMENT CONDITION / PROCEDURE
(1) Receive signal.
E-12cH
Signal strength: 57
± 1dBµV (50 ohm open)
(2) Call "AGC" mode in service mode.
(3) Push "power button", automatically adjust.
WAVEFORM OR OTHERS
Note: For the 50 ohm signal strength gauge,
when not using 50/75 impedance adapter,
signal strength is 57
±1dBµV(50 ohm open),
instead of 59 ±1dBµV(75 ohm open).
precaution: The loss of using impedance
adapter.
CUT OFF, BKGD ADJUSTMENT
NO
1
ADJUSTMENT POINT
AGING
ADJUSTMENT CONDITION / PROCEDURE
(1) Receive PR-99ch (BLUE BACK OFF), "NOISE
PICTURE"
(2) Aging 30 minutes.
WAVEFORM OR OTHERS
1 CRT CUTOFF
ADJUSTMENT
(1) Receive 50Hz Monoscope Pattern Signal.
(2) Set Picture Normal condition.
(3) Select full mode.
(4) Call "RED GAIN" mode in service mode.
(5) Adjust SCREEN VR, so that the value of OSD reach
50h ± 8h. (Fig.1)
07 52 53 54
13 50 51 52
Fig.1
The value of this point
2
WHITE BALANCE
SERVICE MODE ADJ
(1) Receive the "WHITE/BLACK" Pattern SIGNAL.
(2) Press R/C to set Picture NORMAL condition.
(3) Select full mode.
(4) Call "*** GAIN/***CUT OFF" mode in service mode.
(5) Adjust the "RED GAIN","GREEN GAIN","BLUE
GAIN","GREEN CUT OFF", and "BLUE CUT OFF" data
to have a colour temperature of 12300
°K (white).
3
Max Beam Check (1) Receive 50Hz Monoscope Pattern Signal.
(2) Press R/C to set Picture NORMAL condition.
(3) Select full mode.
(4) Connect the DC miliammeter between R611(10K
Ω)
(Full Scale: 3mA Range)
(5) Beam current must be within 1600
±100µA.
Refer to SHIPPING SETTING & CHECKING.
• 12300°KX : 0.272±0.010
Y : 0.275±0.010
(MINOLTA COLOUR ANALYZER CA-100)
*Note: Above Data can be UP/DOWN by
Volume Key.
HIGH 100cd/m
2
± 10cd/m
2
LOW 10.0cd/m
2
± 1cd/m
2
HORIZONTAL, VERTICAL, DEFLECTION LOOP ADJUSTMENT.
NO
1
2
3
4
5
6
7
8
9
10
11
12
ADJUSTMENT POINT
1) 50Hz FULL
V. LINEARITY
(I2C BUS CONTROL)
VERTICAL SHIFT
(I2C BUS CONTROL)
VERTICAL AMP.
(I2C BUS CONTROL)
HORIZONTAL SHIFT
(I2C BUS CONTROL)
EAST -W AST WIDTH
(I2C BUS CONTROL)
PIN PHASE
(I2C BUS CONTROL)
PIN AMP
(I2C BUS CONTROL)
CORNER AMPLITUDE
(I2C BUS CONTROL)
CORNER SYMMETRY
(I2C BUS CONTROL)
VERTICAL ANGLE
(I2C BUS CONTROL)
VERTICAL BOW
(I2C BUS CONTROL)
S CORRECTION
(I2C BUS CONTROL)
2) 50Hz CINEMA
3) 60Hz FULL
4) 60Hz CINEMA
ADJUSTMENT CONDITION / PROCEDURE
(1) Press R/C to set Picture NORMAL condition.
(2) Select full mode.
*Receive 50Hz Monoscope Pattern Signal.
(1) Call the "VERTICAL LINEARITY" mode.
(2) Increase or decrease "VERTICAL LINEARITY" by
Volume key till the horizontal line in the center of
monoscope is just at the position where the blanking
starts.
(1) Call the "VERTICAL SHIFT" mode.
(2) Increase or decrease "VERTICAL SHIFT" by Volume key
till the picture is centered.
(1) Call the "VERTICAL AMPLITUDE" mode.
(2) Increase or decrease "VERTICAL AMPLITUDE" by
Volume key to set overscan of 8% typical.
Adjustment Spec 8% range +1% -1%
(1) Call the "H-CENT" mode.
(2) Increase or decrease "H-CENT" by Volume Key to center
the picture horizontal.
(1) Call the "EAST-WAST WIDTH" mode.
(2) Increase or decrease "EAST-WAST WIDTH" by Volume
key to set overscan of 8% typical.
Adjustment Sepc 8% range +1% -1%
*Receive 50Hz Cross-Hatch Pattern Signal.
(1) Call the "PIN PHASE" mode.
(2) Increase or decrease "PIN PHASE" by Volume key.
(1) Call the "PIN AMP" mode.
(2) Increase or decrease "H-CENT" by Volume key.
(1) Call the "CORNER AMPLITUDE" mode.
(2) Increase or decrease "CORNER AMPLITUDE" by
Volume key.
(1) Call the "CORNER SYMMETRY" mode.
(2) Increase or decrease "CORNER SYMMETRY" by
Volume key.
(1) Call the "VERTICAL ANGLE" mode.
(2) Increase or decrease "VERTICAL ANGLE" by Volume
key.
(1) Call the "VERTICAL BOW" mode.
(2) Increase or decrease "VERTICAL BOW" by Volume key.
(1) Call the "S CORRECTION" mode.
(2) Increase or decrease "S CORRECTION" by Volume key.
Adjust items NO1---NO12, same as 50Hz FULL
In CINEMA mode
V-SIZE Adjustment Spec 25% range +1% -0%
H-SIZE Adjustment Spec 8% range +1% -1%
WAVEFORM OR OTHERS
Note:
V. LINEARITY is the fixation values.
No adjustment.
VERTICAL SHIFT and VERTICAL AMP.
2mm > |A-B| E-5
2mm > |C-D| A face is for south
Adjustment Spec 8.0% range +1% -1%
at the upper side of the geometry center and
the lower side of the geometry center
CORNER SYMMETRY is the fixation values.
No adjustment
VERTICAL ANGLE is the fixation values.
No adjustment
VERTICAL BOW is the fixation values.
No adjustment
Note: Refer to PAGE 9/11
A
B
C
D
4-2
4-1
4
SX76NF8
FOCUS ADJUSTMENT
NO
1
ADJUSTMENT POINT
FOCUS
ADJUSTMENT CONDITION / PROCEDURE
(1) Receive the "Monoscope Pattern" signal.
(2) Press R/C to set Picture NORMAL condition.
(3) Select full mode.
(4) Adjust the focus control to get the best focusing.
(Refer to Adjustment Point as right drawing, SX76NF8
and SX66NF8)
WAVEFORM OR OTHERS
(Adjusted point)
PROTECTOR OPERATION CHECKING
NO
1
2
ADJUSTMENT POINT
H•V PROTECTOR
OTHER
PROTECTOR
ADJUSTMENT CONDITION / PROCEDURE
(1) Receive "Monoscope Pattern" signal.
(2) Connect output of Bias Box to D607 cathode
(3) Set voltage of Bias Box to 18V and make sure the
protector is not work.
(4) Set voltage of Bias Box to 27V, and make sure the
protector is work.
(1) Once finish rectified Electrolytic Capacitor short testing
in + B line, check all possible damaged components on
+B line.
(Use random selected set for inspection)
WAVEFORM OR OTHERS
A/V INPUT AND OUTPUT CHECKING
NO
1
2
3
4
5
6
ADJUSTMENT POINT
AV
OUTPUT CHECK
AV-1
INPUT CHECK
AV-2
INPUT CHECK
AV-1
Component
INPUT CHECK
FRONT
INPUT CHECK
FRONT S-Terminal
INPUT CHECK
ADJUSTMENT CONDITION / PROCEDURE
(1) Receive the "PAL Color Bar" signal (100% White Color
Bar, Sound 400Hz 100% Mod)
(2) Terminate the Video output with a 75 ohm impedance.
Make sure the output is as specified (1.0 Vp-p
± 3dB)
(3) Terminate the Audio output with a 10 Kohm impedance.
Make sure the output is as specified (2.61 Vp-p
± 3dB)
Check of AV
Check of AV
Check of AV
Check of AV
Check of AV
WAVEFORM OR OTHERS
50
Adjust these Horizontal
and Vertical lines
(SX76NF8)
Adjust at "50" position
(SX66NF8)
FUNCTION OPERATION CHECKING (1) (VIDEO & AUDIO)
NO
1
2
3
4
5
6
7
8
9
ADJUSTMENT POINT
CONTRAST
COLOUR
BRIGHTNESS
SHARPNESS
TINT
ECO MODE
COMB FILTER
NTSC HUE
NORMAL
ADJUSTMENT CONDITION / PROCEDURE
(1) Receive "Monoscope Pattern" signal.
(2) Set P-Mode to select CONTRAST.
(3) Press Volume Up/Down key to check whether the
CONTRAST effect is OK or not.
(1) Receive "Color Bar" signal.
(2) Set P-Mode to select COLOUR.
(3) Press Volume Up/Down key to check whether the
COLOUR effect is OK or not.
(1) Receive "Monospcope Pattern" signal.
(2) Set P-Mode to select BRIGHTNESS.
(3) Press Volume Up/Down key to check whether the
BRIGHTNESS effect is OK or not.
(1) Receive "Monoscope Pattern" signal.
(2) Set P-Mode to select SHARPNESS.
(3) Press Volume Up/ Down key to check whether the
SHARPNESS effect is OK or not.
(1) Receive "Monoscope Pattern" signal.
(2) Set PICTURE to TINT select.
(3) Press Volume Up/Down key to check TINT Option,
STANDARD: NORMAL SETTING, WARM for more
REDDISH direction changing, COOL for more BLUISH
direction changing.
(1) Receive "Monoscope Pattern" signal.
(2) Set P-Mode to select ECO MODE.
(3) Press Volume Up/Down key to check whether the ECO
MODE effect is OK or not.
(1) Receive "Color Bar" signal.
(2) Set P-Mode to select COMB FILTER.
(3) Press Volume Up/Down key to check whether the COMB
FILTER effect is OK or not.
(1) INPUT "NTSC Color Bar" signal from AV-input.
(2) Set P-Mode to select NTSC HUE..
(3) Press Volume Up/Down key to check whether the NTSC
HUE effect is OK or not.
(1) In PICTURE Mode, select NORMAL and press menu
button all the settings will be present to normal setting.
(Normal setting value for every mode).
CONTRAST : 80%
COLOUR : 50%
BRIGHTNESS : 50%
SHARPNESS : 50%
TINT : 50%
WAVEFORM OR OTHERS
Notes:
If nothing is display mean contrast, colour,
bright, tint, sharpness are all normal setting.
5-2
5
5-1
SX76NF8
CHECKING FUNCTION OPERATION (2) (VIDEO & AUDIO) CONTINUED
NO
10
11
12
13
14
15
ADJUSTMENT POINT
VOLUME
BALANCE
BASS
TREBLE
SOUND IDENT
DYNAMIC BASS
ADJUSTMENT CONDITION / PROCEDURE
(1) Receive "Monoscope Pattern" signal.
(2) Set S-Mode to select VOLUME.
(3) Press Volume Up/Down key to check whether the
VOLUME effect is OK or not.
(1) Receive "Monoscope Pattern" signal.
(2) Set S-Mode to select BALANCE.
(3) Press Volume Up/Down key to check whether the Left-to
-Right BALANCE effect is OK or not.
(1) Receive "Monoscope Pattern" signal.
(2) Set S-Mode to select BASS.
(3) Press Volume Up/Down key to check whether the BASS
effect is OK or not.
(1) Receive "Monoscope Pattern" signal.
(2) Set S-Mode to select TREBLE.
(3) Press Volume Up/ Down key to check whether the
TREBLE effect is OK or not.
(1) Receive "Monoscope Pattern" signal.
(2) Set S-Mode to select SOUND IDENT.
(3) Press Volume Up/Down key to check whether the
SOUND IDENT effect is OK or not.
(1) Receive "Monoscope Pattern" signal.
(2) Set S-Mode to select DYNAMIC BASS.
(3) Press Volume Up/Down key to check whether the
DYNAMIC BASS effect is OK or not.
WAVEFORM OR OTHERS
CHECKING FUNCTION OPERATION (3) (VIDEO & AUDIO) CONTINUED
NO
16
17
18
19
ADJUSTMENT POINT
VOLUME
Headphone
BALANCE
Headphone
BASS
Headphone
TREBLE
Headphone
ADJUSTMENT CONDITION / PROCEDURE
(1) Connect Headphone
(2) Set S-Mode to select VOLUME in headphone mode.
(3) Press Volume Up/Down key to check whether the
VOLUME effect is OK or not.
(1) Connect Headphone.
(2) Set S-Mode to select BALANCE in headphone mode.
(3) Press Volume Up/Down key to check whether the Left-to
-Right BALANCE effect is OK or not.
(1) Connect Headphone.
(2) Set S-Mode to select BASS in headphone mode.
(3) Press Volume Up/Down key to check whether the BASS
effect is OK or not.
(1) connect Headphone.
(2) Set S-Mode to select TREBLE in headphone mode.
(3) Press Volume Up/ Down key to check whether the
TREBLE effect is OK or not.
WAVEFORM OR OTHERS
CHECKING FUNCTION OPERATION (WIDE MODE)
NO
1
2
3
ADJUSTMENT POINT
WIDE MODE
V-SIZE
in wide mode
V-SCROLL
in wide mode
ADJUSTMENT CONDITION / PROCEDURE
(1) Receive "Monoscope Pattern" signal.
(2) Press WIDE key to check change WIDE mode
AUTO/PANORAMA/FULL/NORMAL/ZOOM14:9/CINEMA
(1) Receive "Monoscope Pattern" signal.
(2) Select PANORAMA, ZOOM14:9, and CINEMA mode.
(3) Select V-SIZE, Press Volume Up/Down key to check
whether the V-SIZE effect is OK or not.
(1) Receive "Monoscope Pattern" signal.
(2) Select PANORAMA, ZOOM14:9, and CINEMA mode.
(3) Select V-SCROLL, Press Volume Up/Down key to check
whether the V-SCROLL effect is OK or not.
WAVEFORM OR OTHERS
6-2
6
6-1
SX76NF8
CHECKING FUNCTION OPERATION (TEXT MODE)
NO
1
2
ADJUSTMENT POINT
TEXT
TEXT key
ADJUSTMENT CONDITION / PROCEDURE
(1) Receive E-12ch signal.
(2) Press TEXT key to check change TEXT mode /
SPLIT SCREEN mode / TELETEXT mode / MIXED
mode.
(1) Receive E-12ch signal.
(2) Press HALF PAGE, HOLD, REVEAL, CLOCK, CANCEL,
LIST, INDEX, and RESET key to check whether each
effect is OK or not.
(3) Select V-SIZE, Press Volume Up/Down key to check
whether the V-SIZE effect is OK or not.
WAVEFORM OR OTHERS
PURITY AND CONVERGENCE ADJUSTMENT
NO
1
ADJUSTMENT POINT
DY location (YPB)
adjustment procedure
ADJUSTMENT CONDITION / PROCEDURE
(1) Turn on the set to make coarse adjustments to the CRT
cut-off, white balance, etc. as well as the purity static
convergence.
(2) To improve the purity adjustment accuracy, perform
coarse adjustments to the H-SIZE/center, V-SIZE/LIN
and side pin.
(3) Enter the video mode to set the beam current to the
standard value below using the screen VR. (Or it is
possible to use the noise signal of an empty channel.)
Age the set for more than 30 minutes with the following
current.
Standard value of beam current: 1000
µA ± 200µA
(4) Receive the monoscope signal to adjust the cut-off
voltage.
Consequently, adjust the contrast, color level and then
set the beam current to the above standard value.
Age the set for more than 2 minutes.
Note: If other adjustments between step 3 and 4 (the
area marked by *) affect the conditions of the beam
current, complete the adjustment for each point within 2
minutes, which is not included in the aging time).
* Perform the adjustments in an earth magnetism room
with Bh and Bv set to 0.20G and -0.50G respectively.
(5) Under the above conditions, move DY and the purity
magnet to make the following adjustments.
- 1. Set YPB of DY to 2.5 mm temporarily.
- 2. Adjust the center to A rank by moving the purity
magnet.
- 3. Insert a temporary wedge to balance DY vertically.
- 4. Move DY back and forth to set L and R to the
standard value below. (Apply to the purity correction
magnet if L and R are imbalanced.)
- 5. Correct the center to "AB rank" if the L and R are
imbalanced.
- 6. After making sure the landing is properly positioned,
fix DY.
Note: Preliminary adjustments are made to set L and R
to the standard value after convergence adjustment.
Standard value: -25
µm ± 5 µm at the 90 mm point
WAVEFORM OR OTHERS
Purity adjustment
Aging for more
than 2 minutes
Aging for more than 30 minutes
Raster
output
PURITY AND CONVERGENCE ADJUSTMENT (Continued)
NO
2
ADJUSTMENT POINT
Peripheral landing
correction
ADJUSTMENT CONDITION / PROCEDURE
(1) Place the set in a magnetic room with the horizontal line
and vertical line set to 0G and - 0.5G respectively, and
receive red monochrome.
(2) After a complete external; demagnetization, generate a
horizontal magnetic field of
±10000nT (0.1G) and apply
the purity correction magnet to the multi-colored areas.
Check blue monochrome equally.
(3) Return the magnetic field to zero and perform a
complete demagnetization.
(4) Generate a reverse horizontal magnetic field, check red
and blue monochrome and apply the magnet to multi-
colored areas.
(5) After correcting the magnet in step 4, check the reverse
magnetic field again.
3 Directional tolerance
check
(1) Place the set in a magnetic room the horizontal line and
vertical line set to 0.2G and - 0.5G respectively, and
receive red monochrome.
(2) Move the set from side to side at the four points of the
compass to check the status of the multiple colors and
ensure L and R are well-balanced.
(3) Apply to the purity correction magnet if L and R are
imbalanced.
(4) If the magnet was applied in step 3, check from other
directions equally.
WAVEFORM OR OTHERS
4 Convergence
adjustment procedure
(1) Set the video adjustment level to normal, and receive a
crosshatch pattern.
(2) Center convergence adjustment
Superimpose RGB of the screen center area for
optimization, by using the 4 pole and 6 pole of the purity
magnet. Superimpose the red and blue by the 4 pole
magnet, the green and magenta by the 6 pole magnet.
As for vertical lines, avoid setting the red line to the left,
blue to the right.
(3) Peripheral convergence adjustment
Combine the following item with the ferrite sheet to make
optimal adjustments.
1.XV cross
Rotate the variable coil on the DY PWB for
optimization.
2.YH cross
Adjust with the volume on the DY PWB.
If peripheral PQH is oversized, correct with the ferrite
sheet or by shaking slightly.
3.XH, YV
Use the dedicated correction strip to correct them.
YH
YV
XV
7-2
7
7-1
SX76NF8
TROUBLE SHOOTING TABLE
NO PICTURE
Does the snow noise appear on
the CRT at max contrast and
brightness control?
Does approx.30V appear
at pin (9) of TU201(tuner)
Check L204, D606 and
R618
Check TU201 and their
peripheral parts.
Check pin(1) and (2) of
IC201
Check pin(51) of IC 1001
Does noise or signal
appear?
Check IC1001 RGB output
Normal?
Check pin(1), (2) and (3) of
IC850 Signal or Noise?
Check R616(Heater), Screen
connection and Peripheral
circuits of T602(FBT) and CRT
Check TU201(tuner),
SF202 and Peripheral
parts.
Check IC201, Q201 and
their Peripheral circuits.
Check IC1001 and their
Peripheral circuits.
Check "CJ" connection,
IC850 and their Peripheral
circuits
Snow noise increase
No Snow noise
(Noise or signal appear)
(Noise)
(Signal)
8
SX76NF8
TROUBLE SHOOTING TABLE
NO SOUND
Check sound setting by R/C.
Siganl should be received.
Check C1302(C1309) Voltage
Approx. 15(-15V)
Check IC1301, IC1302 and Speaker
0V
Check L1302, L1303
D752 and D753
9
SX76NF8
TROUBLE SHOOTING TABLE
NO FUNCTION (NO SOUND AND NO PICTURE)
Is D2201(LED) on a light?
Check IC 1001
94pin INPUT
Check C755 Voltage
Immediately appear
approx. 145V, and turn
to 0V soon.
Check C752 Voltage
Check C715Voltage
Refer to "No
Picture", trouble
shooting
Check IC701,
Q702 and T703
Check IC1001, IC1003,
IC301, IC201, TU201(Refer
to LED FLASHING CODES)
GREEN RED
Approx. 320V
Completely 0V
No Input Pulse
FLASHIN
Check D754 and
IC751
Check Vertical
Circuit
Check Q1012,
D1016 and SP wire
"SS" connection.
0V
Check R718,
F2001 and "AA"
connection
0V
Green
Green
Green
Red
Red
Red
No Light
Immediately appear
approx. 8V, and turn to
0V soon.
Check D752, D753,
C756, C757 and IC752
LED FLASHING CODES
If the TV set does not work and the power LED is flashing "Red <=>Green",
follow the sequence according to the information below, as a guide to fault
finding.
1.Unable to read or write into NMV;66% Green,33% Red twice and Red for
a second.
2.MSP failure;66% Green,33% Red for three times and Red for a second.
3.VCT failure;66% Green,33% Red for four times and Red for a second.
10
SX76NF8
TROUBLE SHOOTING TABLE
NO VERTICAL SCAN
Check the Voltage at pin(15)(1)
of IC502
Normal approx. 14V
Check IC502 and related circuits
Check D601, D605,
R608 and R614
Check IC1001 and
peripheral parts
Check vertical trigger pulse at
pin(12)(13) of IC502
11
SX76NF8
WAVE FORMS
1
4 5 6
2 3
7
10
8
11 12
12
9
13 14 15
SX76NF8
16 17 18
19
20 21
22 23 24
13
SX76NF8
CHASSIS LAYOUT
14
SX76NF8
15
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