Sharp SX-68JS7 SX-68JS9 User manual

1
SX-68JS7
SX-68JS9
SERVICE MANUAL
SHARP CORPORATION
COLOURTELEVISION
Chassis No. SP-60
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
Intheinterestsofuser-safety(Requiredbysafetyregulationsinsomecountries)thesetshouldberestoredtoitsoriginal
condition and only parts identical to those specified should be used.
CONTENTS
Page
• FEATURES..........................................................2
• SPECIFICATIONS ...............................................2
• IMPORTANT SERVICE NOTES ......................... 3
• ADJUSTMENT PRECAUTIONS ......................... 3
• SERVICE MODE..................................................4
• SERVICE ADJUSTMENT ................................... 5
• TROUBLESHOOTING ........................................ 9
• WAVEFORMS ...................................................13
S39E1SX-68JS7
Page
• SOLID STATE DEVICE BASE DIAGRAM ........ 13
• CHASSIS LAYOUT ............................................14
• DESCRIPTION OF SCHEMATIC DIAGRAM.... 15
• SCHEMATIC DIAGRAM ................................... 15
• BLOCK DIAGRAM .............................................26
• PRINTED WIRING BOARD ASSEMBLIES....... 30
• PARTS LIST ......................................................37
COLOUR TELEVISION MODELS SX-68JS7/SX-68JS9SERVICE MANUAL
SX-68JS7
SX-68JS9
MODELS

2
SX-68JS7
SX-68JS9
FEATURES SPECIFICATIONS
Specifications are subject to change without notice.
■Auto search tuning system ■AI-OPC function ■100 CH. program memory ■IGR(B/G) stereo sound ■Black stretch circuit ■CATV hyper band ■Digital comb filter ■2 mode spatializer ■Apertual control circuit (Y/C Transient Improver) ■S Terminal. ■6 language OSD ■7-entertainment menufunction ■ON-TIMER/OFF-TIMER combination use ■Picture noise reduction circuit ■Blue back noise mute ■Front AV-IN terminal & Rear AV in/out terminal. ■AST BOX (SX-68JS9 Only)
Convergence........................................................................Self Convergence System Focus ...............................................................Bi-Potential, Uni-Potential Electroslatic Sweep Deflection ............................................................................................Magnetic Intermediate Frequency Picture IF Carrier........................................................................................38.9 MHz Sound IF Carrier ........................................................................................33.4 MHz Colour Sub-Carrier PAL/NTSC .................................................................................................34.47MHz NTSC ........................................................................................................35.32MHz Power Input.............................................................................. AC 220-240V, 50/60Hz Power Consumption.............................................................................................184W Audio Power Output Rating .................................................................10 W x 2 (Max) Speaker Size ................................................6 x 13 cm Elliptic x 2pcs. + 4 cm Round x 2pcs. Voice Coil Impedance .....................................................................7 ohm at 400 Hz Aerial Input Inpedance ...................................................................... 75 ΩUnbalanced Receiving Channels PAL-B/G VHF ..................................................................................................... AU0 thru 12 UHF...................................................................................................AU28 thru 69 Receiving Frequency VHF ........................................................................... 44.25MHz thru 463.25MHz UHF......................................................................... 471.25MHz thru 863.25MHz

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SX-68JS7
SX-68JS9
IMPORTANT SERVICE NOTES
Maintenance and repair of this receiver should be done by quali- fied service personnel only.
SERVICING OF HIGHVOLTAGE SYSTEM AND PICTURE TUBE When servicing the high voltage system, remove static charge from it by con- necting 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 many produce potentially hazardous radiation with prolonged exposure at close range, the following pre- cautions should be observed: 1. When repairing the circuit, be sure not to increase the high voltage to more
than 34.0 kV (at beam 0µA) for the set.
2. To keep the set in a normal operation, be sure to make it function on 30.5 ±
1.5kV (at beam 1.6mA) 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
repairs, never forget to check for such high voltage after the work.
3. Donotsubstitute apicturetubewith unauthorizedtypesand/or brandswhich
may cause excess X-Ray radiation.
BEFORE RETURNINGTHE RECEIVER Before returning the receiver to the user, perform the following safety checks.
1. Inspect all lead dress to make certain that the 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, insulat-
ing fishpapers, cabinet backs, adjustment and compartment covers or shields, isolation resistor- capacity networks, mechanical insulators etc.
ADJUSTMENT PRECAUTIONS
This model’s setting are adjusted in two different ways: though the I2C bus
control and in the conventional analog manner. The adjustments via the I2C bus
control include preset-only items and variable data.
1. Calling the service mode by the microprocessor.
(1) Set the switch S1006 to the service mode position, and the microprocessor is
put service mode. (Adjustment through the I2C bus control)
(2) Press the CH DOWN key on the remote controller to get ready to select the
modes one by one.
(3) Press the CH UP key on the remote controller to get ready to select the modes
in the order opposite to the above step(2). (See SERVICE MODE)
(4) Using the VOLUME ∧/ VOLUME ∨ keys on the remote controller, the data can
be modified.
(5) Set the switch S1006 to the normal mode (OFF) position, and the microproc-
essor is put out of the service mode.
2. Factory Presettings.
(1) Set the switch S1006 to the service mode position and turn on the main power
switch. Initial values are automatically preset only when a new E2PROM is used (judgement with the first 4 bytes).
(2) The initial data are preset as listed in SERVICE MODE. (3) Some settings should be modfied, and the others should remain as preset. For
details, see SERVICE MODE.
Note: Once the chassis has been put together, be sure to set the switch S1006 to
the service mode position first and then turn on the main power switch (See 2- (1) above). Turning on the power without initializing the E2PROM may caouse
a flow of excess beams.

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SX-68JS7
SX-68JS9
SERVICE MODE
(1) Press the specific keys to change the mode as follows.
RASTER mode CUT-OFF mode 50Hz ADJUST mode
50Hz ADJUST mode
60Hz ADJUST mode SUB-ADJUST mode
SUB-ADJUST mode
V-AMP 50Hz
(V-AMP5)
V-LINE 50Hz
(V-LIN5)
S-CORRECT 50Hz
(V-SCOR5)
V-PHASE 50Hz
(V-PHS5)
H-PHASE 50Hz
(H-PHS5)
H-SIZE 50Hz
(V-SIZE5)
H-COMPENSATION
(H-COM)
EW-PARABOLA
(E/W PAR)
V-BIAS
(V-BIAS)
∫
CORRECTION
(V-
∫
COR)
EW-CORNER
(E/W-COR)
TRAPEZIUM
(TRAPE)
V-COMPENSATION
(V-COM)
In the direction of allow: CH DOWN key In the opposite direction: CH UP key
In the direction of allow: CH DOWN key In the opposite direction: CH UP key
In the direction of allow: CH DOWN key In the opposite direction: CH UP key
SUB-CONTRAST (SUB CON)
SUB-BRIGHT (SUB BRI)
SUB-COLOUR (SUB COL)
SUB-TINT (SUB TIN)
SUB-SHARPNESS (SUB SHP)
SUB-VOLUME (SUB VOL)
60Hz ADJUST mode
V-AMP 60Hz (V-AMP6)
V-LINE 60Hz(V-LIN6)
S-CORRECT 60Hz(V-SCOR6)
V-PHASE 60Hz(V-PHS6)
H-PHASE 60Hz(H-PHS6)
H-SIZE 60Hz (V-SIZE6)
In the direction of allow: CH DOWN key In the opposite direction: CH UP key
(00H) 12H (01H) 37H (02H) 87H (03H) 54H R CUT OFF 384 ~ 1023 384 G CUT OFF 384 ~ 1023 384 B CUT OFF 384 ~ 1023 384 G DRIVE 0 ~ 255 127 B DRIVE 0 ~ 255 127 50Hz V-AMP 0 ~ 127 66 0 *1 50Hz V-LINEARITY 0 ~ 31 22 0 *1 50Hz S-CORRECTION 0 ~ 31 15 0 *1 50Hz V-PHASE 0 ~ 7 4 0 *1 50Hz H-PHASE 0 ~ 31 11 +5 *1 50Hz H-SIZE 0 ~ 63 34 -1 *1 60Hz V-AMP 0 ~ 127 66 60Hz V-LINEARITY 0 ~ 31 22 60Hz S-CORRECTION 0 ~ 31 15 60Hz V-PHASE 0 ~ 7 4 60Hz H-PHASE 0 ~ 31 16 60Hz H-SIZE 0 ~ 63 33 EW-PARABOLA 0 ~ 63 40 V-BIAS 0 ~ 7 4 ∫-CORRECTION 0 ~ 15 15 EW-CORNER 0 ~ 15 8 TRAPEZIUM 0 ~ 63 28 V-COMPENSATION 0 ~ 15 4 H-COMPENSATION 0 ~ 15 4 BELL FILTER 0 ~ 7 4 SECAM R-Y 0 ~ 15 6 SECAM B-Y 0 ~ 15 6
CHROMA GATE PULSE
0 ~ 15 0
SUB-CONTRAST 0 ~ 127 127 SUB-BRIGHT 0 ~ 255 127 SUB-COLOUR 0 ~ 115 55 SUB-TINT 0 ~ 127 63 SUB-SHARPNESS 0 ~ 127 63 SUB-VOLUME 43 ~ 53 53
BS DET SRT POINT (LEVEL)
0 ~ 15 3
8MHz f RESPONCE(RS)
0 ~ 7 0
SRTTRACKING (RTC) 0 ~ 7 4 V/C/J BS (BS) 0 ~ 1 0
E2PROM item Data adjustable range Data initial value Remarks
To go to the service mode, the data at the E2PROM's addresses 00H thru 03H are read. If the data ae no as given below, the E2PROM is initialized according to the table below.
Address: Data
00H: 12H 02H: 87H 01H: 37H 03H: 54H

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SX-68JS7
SX-68JS9
Key input Mode
(6) If key in the remote control key as kelow, it will directly switch to the mode coneerned.
TEXT/MIX BELL FILTER INDEX GATE PILSE SIZE SUB BRIGHT TIMED PAGE SUB COLOUR HOLD SUB TINT REVEAL LEVEL YELLOW SUB VOLUME CYAN (FLOF 4) SUB CUNTRAST RED (FLOF 1) H-POSITION GREEN (FLOF 2) V-POSITION STORE
SUB H-PULSE DELAY 50Hz
FLOF/LIST
SUB H-PULSE DELAY 60 Hz
User data
CONTRAST 60 COLOUR 0 BRIGHTNESS 0 TINT 0 SHARPNESS 0 S-VOL 0 TREBLE 0 BASS 0 WHITE TEMP 0 BALANCE 0 SPATIALIZER OFF AI-OPC OFF BLUE BACK OFF C SYSTEM AUTO PICTURE NR OFF
(4) While changing mode, EEPROM will memorize the service data. (5) In the service mode, the user data are preset as follows.
SERVICE ADJUSTMENT
PIF/AFT/AGC ADJUSTMENT
1. Get the tuner ready to receive the E-9CH
signal,butwithnosignalinput.Adjust PLL data.
2. Connect the sweep generator's output cable
to the tuner antenna. (RF sweep)
3. Adjust the sweep generator's output level to
80dBµV.
4. Connect the responce lead (use a low-imped-
ance probe with wave detector;see
Fig.1
.) to
the tuner's IF output terminal. (Thisterminal must havethe probealonecon- nected.)
5. Set the RF AGC voltage to 0-6V with no con-
tact with waveform.
6. Adjust the tuner IF coil to obtain the waveform
as shown in
Fig.2
.
Note: Be sure to keep the tuner cover in position
during this adjustment.
1. TUNER IFT (preset) ADJUSTMENT:TU201(preset)
1000p
1000p
10kΩ
75Ω100kΩOscilloscope
IF-OUT
E9CH
- 1.5dB±0.8dB
PC
* Turn the core counterclockwise for the
UP direction, and clockwise for the DOWN direction. Adjust the T201 core to point B (between B' and B''). Point A and C are rejectable.
DC voltage at TP201
6V
3.3V
DOWN A B' B B'' C UP
2. COIL ADJUSTMENT:T201 (VCO)
1. Receive the E-12ch (PAL colour bar) signal.
Ifthis signal isnotavailable,anysignalabove the E-5CH band is acceptable. • Field strength: 55-80 dBµV Make sure the frequecy is almost the same as that of the received channel (±30 kHz).
2. Using the channel setting control, make a
frequency of 224.25 MHz appear on the screen. (AFT off) (If any other channel than E-12CH is received, make its frequency on the screen.)
3. Adjust T201 so that the DC voltage at the
SFT OUT terminal (TP201) be 4.5 ±0.1V.
4. TurnT201 clockwise to have a 8V point and
counterclockwiseto 0.2V thenadjustthe coil position in the middle of the above range.
E2PROM item Data adjustable range Data initial value Remarks
NICAM ERROR AUTO (N-AMDIS)
0 ~ 1 0
V-ENHANCEMENTLEVEL (V-ENH)
0 ~ 7 4
COLOUR BANDPASS FILTER (CBPF)
0 ~ 1 0
1 LINE DOT IMPROVEMENT (LD)
0 ~ 1 0
CORING 0 ~ 1 0
*1: While 50Hz. Mode has been adjusted, 60Hz. Mode's data automatically will be input.
(But while 60Hz mode has been adjusted, 50Hz mode's data won't be updataed.)