Casio SY-20B User manual

SY-20B (KX-529B)
R
MAY. 2000
SY-20B
(without price)
INDEX

CONTENTS
SPECIFICATIONS ......................................................................................... 1
BLOCK DIAGRAM ........................................................................................ 2
ADJUSTMENT............................................................................................... 3
PRINT CIRCUIT BOARDS ............................................................................ 8
EXPLODED VIEW ....................................................................................... 10
PARTS LIST ................................................................................................ 11
SCHEMATIC DIAGRAMS ........................................................................... 13
DRIP-PROOF PERFORMANCE Q & A....................................................... 15

— 1 —
Item Specification
1. Type LCD Color Television
2. Reception Frequencies: UHF: UHF band CH 14 – CH 69
VHF: VHF band CH 2 – CH 13
3. Display Element: High resolution color liquid crystal display
(Super Twisted Nematic Type)
4. Drive System: Passive matrix system
5. Screen Size: 2.3 inches
6. Backlight: High luminance fluorescent material
7. Antenna: Rod antenna (VHF, UHF)
8. Speaker: 12/16ø inches (28 mm) X1
9. Connection Terminals: External antenna jack (3.5ø mini)
Earphone jack (3.5ø mini)
External power source jack (DC 6V)
Audio/Video input jack (3.5ø mini)
10. Power Supply: 3-way power supply system
Batteries: 4 AA-size dry batteries
AC: AC adaptor AD-K64/AD-K65 (option)
Car battery: Car adaptor CA-K65 (option)
11. Power Consumption: Approx. 3.6 W
12. Ambient Temperature Range: 32°F (0°C) ~ 104°F (40°C)
13. Dimensions: 56/16" (W) X 23/16" (D) X 36/16" (H) inches
136 (W) X 56 (D) X 85 (H) mm
14. Weight: Approx. 9.2 oz 260 g (excluding batteries)
SPECIFICATIONS

— 2 —
BLOCK DIAGRAM
LCD DRIVER (5151)
CH
UPKEY CH DOWNKEY
LAMP
Vcc1-1,GND
Vcc2-0,GND
V1,V3,V0,V4,VC
CK1,CK2
D1 ~ 6
SNB,STB
CNB2,CDB2,CFB2
EN1,EN2
MODULE
POWER
SUPPLY
MODULE
CONTROLL
SIGNAL
AUDIO2
Vcc7 VEE1
Vcc2
Vcc1-1
AVB
VIDEO2
AUDIO1 VIDEO1
A-MUTE
RGB
HD
C-SYNC
AUDIO1 VIDEO1
H/L
U/V
AFT
Vcc2-8
TU
Vcc7
BT
ANT AGC
Vcc1-1
Vcc2 (4V)
Vcc2 (4.0V)
Vcc7 (40V)
VEE1 (-5V)
AFT
A-MUTE
EAR PHONE
EXTERNAL ANT
BATTERY 1.5V x 4
AC ADAPTOR 6V
EXTERNAL VIDEO
EXTERNAL AUDIO
BV BS
U/V
BT
CN900
Vcc2-8,GND
KDB,SP+,SP-
CN701
CN950
CN700
Vcc2
TUNER
(TNS-010US)
ANT
JACK PRE
AMP SAW
FILTER VIF/SIF
(M51348FP)
CHROMA
(M52042FP)
TUNING
BT GEN
(BA10358) VOLTAGE
SUPLLY
FOR LCD
DRIVER
AV JACK
LCD
INVERTER
TRANS
LCD
DRIVER
(651)
A/D CONVERTER
CONTROLLER
(OM6006)
AUDIO AMP
(NJM2070M)
POWER SW
BAND SW DC/DC
CONVERTER
TRANS
LCD DRIVER
(651)
L-PCB
BL-PCB
LCM
SW PCB
LCD DRVER(5151)
SP
SP

— 3 —
ADJUSTMENT
1. Vcc2 adjustment, Vcc7, Vee1 voltage check
2. LLD coil adjustment
3. Free running frequency adjustment
4. Contrast adjustment
5. TINT adjustment
Preparations
1. Connect AVB (CP725) to GND.
2. Set SW100 on UHF mode.
Adjustment And Test Point Locations
Top View
BottomView
T 200
VR 300
VR 301
VR 100
CP 102
CP 101 CP 305
CP 238
CP 320 CP 300
CP 740
CP 104
CP 103 CP 729
CP 701

— 4 —
Adjustment procedures
1. Vcc2 adjustment, Vcc7, VEE1 voltage check
•Condition
(1) Signal
No signal
(2) Other conditions
Power supply: Vcc1-1 (CP101) = 5.00 ±0.05 [V]
•Adjustment
Apply 5.00 ±0.05 [V] on Vcc1-1 (CP101).
Adjust VR100 so that Vcc2 (CP102) voltage becomes 4.00 ±0.02 [V].
•Checking
Vcc7 (CP103) = 36.0 ~ 44.0 [V]
VEE1 (CP104) = –4.50 ~ –6.00 [V]
•Block diagram
2. LLD coil adjustment
•Conditions
(1) Signals
Broadcasting system: M/M
Color system: NTSC color bar
(2) Signal level
Input electric field: 40 ±5 dBµ(IF AGC full gain), P/S = 10 dB
(3) Other conditions
US IF (Input electric field: terminated with 75 Ωresistance)
Power supply: Vcc1-1 (CP101) = 5.00 ±0.05 [V]
•Adjustment
Monitor video detection signal (CP238) via a low-pass filter of 100 kHz cutoff frequency and adjust LLD coil
T200 so that its DC level is minimum (waveform’s amplitude is maximum).
•Confirmation
There should be no waveform distortion (erroneous synchronization, etc.), under sensitivity (video detector
output level is abnormally small, etc.).
•Block diagram
VDigital
Voltmeter
L-PCB
Stabilizer
Vcc1-1
Vcc7
Vcc2
VEE1
Vcc1-1
IF signal
L-PCB
Adjust to minimize the DC level.
Oscilloscope
DC IN
Detector OUT
Signal
generator
Stabilizer
Low-Pass Filter

— 5 —
3. Free running frequency adjustment
•Conditions
(1) Signal
No signal (NTSC standard signal should be applied only at synchronous check)
(2) Signal level
Input electric field only at synchronous check: 70 ±3 dBµ(terminated with 75Ωresistance),
P/S = 10 dB
(3) Other conditions
US IF input only at synchronous check (input electric field with 75 Ωtermination).
Connect SYF terminal (CP729) and Vcc2-7 (CP701).
Power supply: Vcc1-1 (CP101) = 5.00 ±0.05 [V]
Room temperature: 20 ±10 [°C]
•Adjustment
Monitoring HDB (CP305) with a frequency counter, adjust VR700 so that the frequency is 15.734 ±0.1 [kHz].
•Caution
(1) Disconnect the wire between SYF terminal. Applying IF signal make sure that synchronization is normal
on the display.
(2) Use input signal pattern conforming CCIR standard.
•Block diagram
L-PCB
SYF
Vcc2-7
HD Frequency
Counter
Vcc1-1
IF signal
Signal
generator
Stabilizer

— 6 —
4. Contrast adjustment
• Conditions
(1) Signals
Broadcasting system: M/M
Color system: NTSC color bar (white 75%)
(2) Signal level
Input electric field: 70 ±3 dBµ(terminated with 75Ωresistance), P/S = 10 dB
(3) Others
US IF input (input electric field should be terminated with 75Ωresistance)
Power supply : Vcc1-1 (CP101) = 5.00 ±0.05 V
•Adjustment
(1) Connect color terminal (CP320) to GND (CP300) so that screen becomes black and white.
(2) Adjust contrast pot VR300 so that the voltage between pedestal level and white level of B signal
(CP740) is 0.80 ±0.05 [V].
•Caution
(1) Make sure that waveforms are not distorted.
(2) Connect COLOR terminal of Chroma IC (M52042FP) to GND.
(3) Monitor the B output signal with an oscilloscope via a low-pass filter (C = 2700 pF, R = 100 Ω).
•Block diagram
L-PCB
Vcc1-1
IF signal
Signal
generator
Stabilizer
B output
Low-pass filter Oscilloscope

— 7 —
5. TINT adjustment
•Condition
(1) Signal
Broadcasting system: M/M
Color system: NTSC color bar (white 75%)
(2) Signal level
Input electric field: 70 ±3 dBµ(75Ωtermination), P/S = 10 dB
(3) Other conditions
US IF input (input electric field should be terminated with 75Ωresistance).
Power suppiy : Vcc1-1 (CP101) = 5.00 ±0.05 [V]
•Adjustment
Observing B output signal (CP740) with an oscilloscope, adjust TINT pot VR301 so that amplitude difference
between two center pulses is 0.1 [V]
•Caution
(1) Do not connect COLOR chroma IC (M52042PP) terminal of to GND.
(2) Monitor B output signal with an oscilloscope via a low-pass filter (C = 2700 pF, R =100 Ω)
•Block diagram
VCC1-1
IF signal
Signal
generator
Stabilizer
L-PCB
B output
Oscilloscope
Low-pass filter

— 8 —
PRINTED CIRCUIT BOARDS
TOP VIEWS
Linear
Connector