Akai 29CT24FS User manual

SERVICE MANUAL
Models:
29CT24FS
29CT71FS
www.akai.ru
COLOUR TV SET

SERVICE MANUAL
TABLE OF CONTENTS
SPECIFICATIONS............................................................................................................. 1
SAFETY INSTRUCTIONS AND MAINTENANCE......................................... 2
X-RAY RADIATION PRECAUTION.......................................................................................... 2
SAFETY PRECAUTION.............................................................................................................. 2
PRODUCT SAFETY NOTICE.................................................................................................... 3
SAFETY SYMBOL DESCRIPTION........................................................................................... 3
MAINTENANCE............................................................................................................................ 4
ADJUSTMENTS.................................................................................................................. 5
SET-UP ADJUSTMENTS ........................................................................................................... 5
CIRCUIT ADJUSTMENTS.......................................................................................................... 8
STRUCTURE AND CHASSIS FUNCTION DESCRIPTION.................... 18
STRUCTURE BLOCK DIAGRAM ............................................................................................. 18
BLOCK DIAGRAM FOR SUPPLY VOLTAGE SYSTEM ...................................................... 19
CHASSIS DESCRIPTION ...........................................................................................................20
SERVICE DATA .................................................................................................................21
TECHNICAL DATA OF KEY ICS ...............................................................................................21
SERVICE DATA OF KEY ICS ....................................................................................................43
REPLACEMENT OF PARTS.......................................................................................................46
APPENDIX
1. CIRCUIT DIAGRAM
2. FINAL ASSEMBLY DIAGRAM
3. FINAL WIRING DIAGRAM
4. PRINTED CIRCUIT BOARD LAYOUTS
1

SERVICE MANUAL
SPECIFICATIONS
Table 1 Specifications
Model Number 29CT24FS, 29CT71FS
Color system PAL, SECAM
RF system
Sound system B/G, D/K
Video system PAL4.43, SECAM, NTSC3.58, NTSC4.43 (50/60Hz)
Programs preset 236(0-235)
Antenna input 75 (unbalanced)
Picture tube (Approx.)
Effective screen dimensions
478 363mm
Video/Audio inputs Composite-3; component-1; S-video-1
Power source 170-260V ~, 50Hz
Weight (Approx.) 30kg
Rated power consumption 110 W
Designs and specifications are subject to change without notice.
1
Video/Audio outputs Composite - 1

SERVICE MANUAL
INSTRUCTIONS FOR SERVICE SAFETY AND MAINTENANCE
WARNING: BEFORE SERVICING THIS CHASSIS, READ THE “ X-RAY
RADIATION PRECAUTION ” , “ SAFETY PRECAUTION ” AND “ PRODUCT
SAFETY NOTICE ” INSTRUCTION BELOW.
X-RAY RADIATION PRECAUTION
1. The EHT must be checked every time the TV is serviced to ensure that the CRT does not emit
X-ray radiation as result of excessive EHT voltage. The maximum EHT voltage permissible in
any operating circumstances must not exceed the rated value. When checking the EHT, use
the High Voltage Check procedure in this manual using an accurate EHT voltmeter.
2. The only source of X-RAY radiation in this TV is the CRT. The TV minimizes X-RAY radiation,
which ensures safety during normal operation. To prevent X-ray radiation, the replacement
CRT must be identical to the original fitted as specified in the parts list.
3. Some components used in this TV have safety related characteristics preventing the CRT from
emitting X-ray radiation. For continued safety, replacement component should be made after
referring the PRODUCT SAFETY NOTICE below.
4. Service and adjustment of the TV may result in changes in the nominal EHT voltage of the
CRT anode. So ensure that the maximum EHT voltage does not exceed the rated value after
service and adjustment.
SAFETY PRECAUTION
WARNING: REFER SERVICING TO QUALIFIED SERVICE PERSONNEL ONLY.
1. The TV has a nominal working EHT voltage. Extreme caution should be exercised when
working on the TV with the back removed.
1.1 Do not attempt to service this TV if you are not conversant with the precautions and procedures
for working on high voltage equipment.
1.2 When handling or working on the CRT, always discharge the anode to the TV chassis before
removing the anode cap in case of electric shock.
1.3 The CRT, if broken, will violently expel glass fragments. Use shatterproof goggles and take
extreme care while handling.
1.4 Do not hold the CRT by the neck as this is a very dangerous practice.
2. It is essential that to maintain the safety of the customer all power cord forms be replaced
exactly as supplied from factory.
3. Voltage exists between the hot and cold ground when the TV is in operation. Install a suitable
isolating transformer of beyond rated overall power when servicing or connecting any test
equipment for the sake of safety.
4. When replacing ICs, use specific tools or a static-proof electric iron with small power (below
35W).
5. Do not use a magnetized screwdriver when tightening or loosing the deflection yoke assembly
to avoid electronic gun magnetized and decrement in convergence of the CRT.
2

SERVICE MANUAL
6. When remounting the TV chassis, ensure that all guard devices, such as nonmetal control
buttons, switch, insulating sleeve, shielding cover, isolating resistors and capacitors, are
installed on the original place.
7. Replace blown fuses within the TV with the fuse specified in the parts list.
8. When replacing wires or components to terminals or tags, wind the leads around the terminal
before soldering. When replacing safety components identified by the international hazard
symbols on the circuit diagram and parts list, it must be the company-approved type and must
be mounted as the original.
9. Keep wires away from high temperature components.
PRODUCT SAFETY NOTICE
CAUTION: FOR YOUR PROTECTION, THE FOLLOWING PRODUCT SAFETY NOTICE
SHOULD BE READ CAREFULLY BEFORE OPERATING AND SERVICING THIS TV SET.
1. Many electrical and mechanical components in this chassis have special safety-related
characteristics. These characteristics are often passed unnoticed by a visual inspection and
the X-ray radiation protection afforded by them cannot necessarily be obtained by using
replacements rated at higher voltages or wattage, etc. Components which have these special
safety characteristics in this manual and its supplements are identified by the international
hazard symbols on the circuit diagram and parts list. Before replacing any of these components
read the parts list in this manual carefully. Substitute replacement components which do not
have the same safety characteristics as specified in the parts list may create X-ray radiation.
2. Do not slap or beat the cabinet or CRT, since this may result in fire or explosion.
3. Never allow the TV sharing a plug or socket with other large-power equipment. Doing so may
result in too large load, causing fire.
4. Do not allow anything to rest on or roll over the power cord. Protect the power cord from being
walked on, modified, cut or pinched, particularly at plugs.
5. Do not place any objects, especially heavy objects and lightings, on top of the TV set. Do not
install the TV near any heat sources such as radiators, heat registers, stove, or other
apparatus that produce heat.
6. Service personnel should observe the SAFETY INSTRUCTIONS in this manual during use and
servicing of this TV set. Otherwise, the resulted damage is not protected by the manufacturer.
SAFETY SYMBOL DESCRIPTION
The lightning symbol in the triangle tells you that the voltage inside this product
may be strong enough to cause an electric shock. Extreme caution should be
exercised when working on the TV with the back removed.
This is an international hazard symbol, telling you that the components identified
by the symbol have special safety-related characteristics.
FDA This symbol tells you that the critical components identified by the FDA marking
have special safety-related characteristics.
UL This symbol tells you that the critical components identified by the UL marking
3

SERVICE MANUAL
have special safety-related characteristics.
C UL This symbol tells you that the critical components identified by the C-UL marking
have been evaluated to the UL and C-UL standards and have special
safety-related characteristics.
VDE
This symbol tells you that the critical components identified by the VDE marking
have special safety-related characteristics.
MAINTENANCE
1. Place the TV set on a stable stand or base that is of adequate size and strength to prevent it
from being accidentally tipped over, pushed off, or pulled off. Do not place the set near or
over a radiator or heat register, or where it is exposed to direct sunlight.
2. Do not install the TV set in a place exposed to rain, water, excessive dust, mechanical
vibrations or impacts.
3. Allow enough space (at least 10cm) between the TV and wall or enclosures for proper
ventilation.
4. Slots and openings in the cabinet should never be blocked by clothes or other objects.
5. Please power off the TV set and disconnect it from the wall immediately if any abnormal
condition are met, such as bad smell, belching smoke, sparkling, abnormal sound, no
picture/sound/raster. Hold the plug firmly when disconnecting the power cord.
6. Unplug the TV set from the wall outlet before cleaning or polishing it. Use a dry soft cloth for
cleaning the exterior of the TV set or CRT screen. Do not use liquid cleaners or aerosol
cleaners.
4

SERVICE MANUAL
ADJUSTMENTS
SET-UP ADJUSTMENTS
The following adjustments should be made when a complete realignment is required or a new
picture tube is installed.
Perform the adjustments in the following order:
1. Color purity
2. Convergence
3. White balance
Notes:
①The purity/convergence magnet assembly and rubber wedges need mechanical
positioning. Refer to Fig1, 2.
②For some picture tubes, purity/ convergence adjustments are not required.
1. Color Purity Adjustment
Preparation:
Before starting this adjustment, adjust the vertical sync, horizontal sync, vertical amplitude and
focus.
1.1 Face the TV set north or south.
1.2 Connect the power plug into the wall outlet and turn on the main power switch of the TV set.
1.3 Operate the TV for at least 15 minutes.
1.4 Degauss the TV set using a specific degaussing coil.
1.5 Set the brightness and contrast to maximum.
1.6 Counter clockwise rotate the R /B low brightness potentiometers to the end and rotate the
green low brightness potentiometer to center.
1.7 Receive green raster pattern signals.
1.8 Loosen the clamp screw holding the deflection yoke assembly and slide it forward or backward
to display a vertical green zone on the screen. Rotate and spread the tabs of the purity magnet
around the neck of the CRT until the green zone is located vertically at the center of the screen.
1.9 Slowly move the deflection yoke assembly forward or backward until a uniform green screen is
obtained.
1.10 Tighten the clamp screw of the assembly temporarily. Check purity of the red raster and blue
raster until purities of the three rasters meet the requirement.
2. Convergence Adjustment
Preparation:
Before attempting any convergence adjustment, the TV should be operated for at least 15
minutes.
2.1 Center convergence adjustment
2.1.1 Receive dot pattern.
2.1.2 Adjust the brightness/contrast controls to obtain a sharp picture.
2.1.3 Adjust two tabs of the 4-pole magnet to change the angle between them and red and blue
vertical lines are superimposed each other on the center of the screen.
5

SERVICE MANUAL
Yok
Fig. 1
2.1.4 Turn both tabs at the same time keeping the angle constant to superimpose red and blue
horizontal on the center of the screen.
2.1.5 Adjust two tabs of the 6-pole magnet to superimpose red/blue line and green line.
2.1.6 Remember red and blue movement. Repeat steps 2.1.3)～2.1.5) until optimal convergence is
obtained.
2.2 Circumference convergence adjustment
2.2.1 Loosen the clamp screw holding the deflection yoke assembly and allow it tilting.
2.2.2 Temporarily put the first wedge between the picture tube and deflection yoke assembly.
Move front of the deflection yoke up or down to obtain better convergence in circumference.
Push the mounted wedge in to fix the yoke temporarily.
2.2.3 Put the second wedge into bottom.
2.2.4 Move front of the deflection yoke to the left or right to obtain better convergence in
circumference.
2.2.5 Fix the deflection yoke position and put the third wedge in either upper space. Fasten the
deflection yoke assembly on the picture tube.
2.2.6 Detach the temporarily mounted wedge and put it in either upper space. Fasten the
deflection yoke assembly on the picture tube.
2.2.7 After fastening the three wedges, recheck overall convergence and ensure to get optimal
convergence. Tighten the lamp screw holding the deflection yoke assembly.
3. White Balance Adjustment
Generally, white balance adjustment is made with professional equipment. It’s not practical to
get good white balance only through manual adjustment. For TVs with I2C bus control, change
the bus data to adjust white balance.
6

SERVICE MANUAL
Center Convergence by Convergence Magnets
Incline the Yoke Up (or Down) Incline the Yoke Right (or Left)
Fig. 2
4-pole Magnet Movement 6-pole Magnet Movement
Circumference Convergence by DEF Yoke
Fig.3
7

SERVICE MANUAL
CIRCUIT ADJUSTMENTS
Preparation:
Circuit adjustments should be made only after completion of set-up adjustments.
Circuit adjustments can be performed using the adjustable components inside the TV set. For TVs
with I2C bus control, first change the bus data.
1. Degaussing
A degaussing coil is built inside the TV set. Each time the TV is powered on, the degaussing
coil will automatically degauss the TV. If the TV is magnetized by external strong magnetic field,
causing color spot on the screen, use a specific degausser to demagnetize the TV in the
following ways. Otherwise, color distortion will be shown on the screen.
1.1 Power on the TV set and operate it for at least 15 minutes.
1.2 Receive red full-field pattern.
1.3 Power on the specific degausser and face it to the TV screen.
1.4 Turn on the degausser. Slowly move it around the screen and slowly take it away from the TV.
1.5 Repeat the above steps until the TV is degaussed completely.
2. Confirmation and Adjustment for Voltage
Caution: +B voltage has close relation to high voltage. To prevent X-ray radiation, set +B
voltage to the rated value.
2.1 Power on the TV and receive Philips test pattern.
2.2 Check the resistors and coils for being burned. (If the fuse is burned out, do not power on the
TV again until the cause is found out.)
2.3 ---Measure voltages of test points with the digital voltmeter. Measure the CRT high voltage with
the high-voltage testing equipment and heater voltage with the high-frequency effective
voltmeter. The rated values are shown as below.
Table 2
Test Point Voltage (V) Test Point Voltage (V)
Negative of VD871 82V±5V in standby
134±1.5V in use Positive of C414 5±0.5V
Positive of C879 5±0.5V Positive of C412 9±0.5V
Positive of C882 9±0.5V Negative of VD872 16±1V
Positive of C117 32±1V Negative of VD873 16±1V
Negative of VD402A 12.5±1V Negative of VD874 16±1V
Negative of VD404 27±1.5V Negative of VD403 190±5.0V
Heater 6.3+0.2\-0.3Vrms CRT anode 29.5±1.2KV
3. High Voltage Inspection
Caution: No high voltage adjustment components inside the chassis. Please perform
high voltage inspection in the following ways.
3.1 Connect a precise static high voltmeter to the second anode (inside the high voltage cap) of the
CRT.
3.2 Plug in the supply socket (150-250V, AC) and turn on the TV. Set the brightness and contrast
8

SERVICE MANUAL
to minimum (0μA).
3.3 The high voltage reading should be less than the limited EHT voltage.
3.4 Change the brightness from minimum to maximum, and ensure high voltage not beyond the
limitation in any case.
Nominal EHT voltage: 29.5±1.2KV Limited EHT voltage: 32KV
4. Focus Adjustment
Caution: Dangerously high voltages are present inside the TV. Extreme caution should
be exercised when working on the TV with the back removed.
4.1 After removing the back cover, look for the FBT on the main PCB. There should be a FCB on
the FBT.
4.2 Power on the TV and preheat it for 15 min.
4.3 Receive a normal TV signal. Rotate knob of the FCB until you get a sharp picture.
BeforeAdjusting AfterAdjusting
Fig. 4
5. Safety Inspection
5.1 Inspection for insulation and voltage-resistant
Perform safety test for all naked metal of the TV. Supply high voltage of 3000V AC, 50Hz (limit
current of 10mA) between all naked metal and cold ground. Test every point for 3 sec. and
ensure no arcing and sparking.
5.2 Requirements for insulation resistance
Measure resistance between naked metal of the TV and feed end of the power cord to be
infinity with a DC-500 high resistance meter and insulation resistance between the naked metal
and degaussing coil to be over 20MΩ.
6. SERVICE mode
6.1 To enter the SERVICE mode
Set the volume to 0 by the remote control. Then press and hold the MUTE button on the
remote control and MENU button on the TV at the same time for over 2 seconds. In the S mode,
ress the POWER button to quit the S mode.p
S
(“S”is red and other items are yellow.)
9

SERVICE MANUAL
Use the ↓/↑buttons on the remote control to highlight an adjustment and the ←/→buttons
to adjust it.
The POS+/-,↑/↓/←/→,1~6, RECALL, VOL+/-, MUTE and POWER buttons on the remote
control function in the S mode, but 100+, 7, 8, 9 and 0 buttons not.
6.2 Adjustments for Service mode and design mode
Table 3
：
Bit Function Description Status
Bit7.6 Audio system options (available during auto search
and use of AUTO button) 00: B/G 01: I 10: D/K 11: M
Bit5 Function switchover for CPU’s Pin 61 0: External mute 1: Audio system switchover
Bit4 V MUTE When changing channels: 0: Y- mute 1: RGB mute
Bit3
Bit2 SECAM gate pulse width 00: 2.2μS 01:2.0μS
10:1.8μS 11: SECAM decoding disabled
Bit1 SECAM 0:No 1:Yes
MODE0
Bit0 Fixed to 00
Bit7 Write-in LOGO option 0: No 1:Yes
Bit6 Power-on modes 0: Memory on 1: Soft on
Bit5 Step length setting for lighting up gradually during
power-on 1：Large step 0: Small step
Bit4 Screen saver setting 0: No 1: Yes
Bit3 Moption 0:No 1:Yes
Bit2 D/Koption 0:No 1:Yes
Bit1 Ioption 0:No 1:Yes
MODE1
Bit0 B/Goption 0:No 1:Yes
Bit7 Arabic numeral 0: Yes 1: No
Bit6 DVD setting bit for AV board TC90L01 0: No 1: Yes
Bit5 Tiltcorrectionsettingbit 0:No 1:Yes
Bit4 “SVM”in PICTURE menu 0: No 1: Yes
Bit 3 TA1343/NICAM woofer output setting 0: Mono output 1: Overlapped to main channel
Bit 2 “WOOFER”in SOUND menu 0: No 1: Yes
Bit 1 Black-screen time setting 0: Short time 1: If OPT.2 = 1, long time; OPT.2 = 0, short
time
MODE2
Bit.0 BBE AGC option 1: 300mv 0: 150mv
BIT 7 Relay switch option 1: Yes 0: No
BIT 6 Instant power-on option 1: Yes 0:No
BIT 5.4 Fixed to 00
BIT 3 BBE/SRS IC 1: Yes 0: No
BIT 2
MODE3
BIT 1
TA1218
Multi AV switch options BIT 0 BIT 1 BIT2 0 0 0 TV-AV1(S)-AV2-AV3(S)-DVD
0 0 1 TV-AV1(S)-AV2-AV3(S)
0 1 0 TV-AV1(S)-AV2-DVD
0 1 1 TV-AV1(S)-AV2
(continued)
10

SERVICE MANUAL
BIT 0 1 0 0 TV-AV1(S)-AV3(S)-DVD
1 0 1 TV-AV1(S)-AV3(S)
1 1 0 TV-AV1(S)-DVD
1 1 1 TV-AV1
BIT 7 TC90A49 option 0: No 1: Yes
BIT 6 TA1343 option 0: No 1: Yes
BIT 5 TC90L01 option 0: No 1: Yes
BIT 4 TA1218 option 0: No 1: Yes
BIT 3 NA
BIT 2 NJW1161 option 0: No 1: Yes
BIT 1 NJW1160 option 0: No 1: Yes
MODE4
BIT 0 NJW1137 option 0: No 1: Yes
BIT7 Arabic 0:No 1:Yes
BIT6 Farsi 0:No 1:Yes
BIT5 Malay 0:No 1:Yes
BIT 4 Indonesian 0: No 1: Yes
BIT3 Russian 0:No 1:Yes
BIT2 German 0:No 1:Yes
BIT1 French 0:No 1:Yes
LANG-OPT
When only with
single
language
option, reset
the CPU to
enable the
options.
BIT0 English 0:No 1:Yes
LANG-OUT Ex-factory language options with AUTO key 00: English 01: French 02: German 03: Russian
04: Indonesian 05: Malay 06: Farsi 07: Arabic
Bit 7 Interval between relay on and off 0: No 1: Yes
Bit 6 VCO adjustments 0: PIF VCO functions (PIFVCO = 10) during auto search and
search；
1: PIFVCO = 10 during turn-on，and PIFVCO = 00 in Normal
mode
Bit 5 Audio processing 1: Yes 0: No
Bit 4 Large-amplitude AFT switch when no signal 1: Off 0: On
Bit 3 Audio gain switch 1: Off 0: On
Bit 2 Usage of Y-mute 0: No 1: Yes
Bit 1 Thailand B/G (5.74M) 1: Yes 0: No
OPT
Bit 0 Single audio system 1: Yes 0: No
OSD Horizontal position of OSD
RCUT R cut off
GCUT G cut off
BCUT B cut off
GDRV G drive
BDRV B drive
CNTX Contrast Max.
BRTC Brightness center
(continued)
11

SERVICE MANUAL
COLC Color center (for NTSC)
TNTC Tint center (for NTSC)
TNTCAV Tint center (for NTSC IN AV)
COLP Color center (for PAL)
COLS Color center (for SECAM)
DCOL DVD color
SCOL Sub color center (for DVD)
SCNT Y- sub contrast
CNTC Contrast center
CNTN Contrast Min.
BRTX Brightness Max.
BRTN Brightness Min.
COLX Color Max.
COLN Color Min.
TNTX Tint Max.
TNTN Tint Min.
ST3 Sharpness center for NTSC 3.58 (TV)
SV3 Sharpness center for NTSC 3.58 (VIDEO)
ST4 Sharpness center for other color system (TV)
SV4 Sharpness center for other color system (VIDEO)
SVD Sub Sharpness center in DVD
ASSH Asymmetry sharpness
SHPX Sharpness Max.
SHPN Sharpness Min.
TXCX Text RGB in user contrast Max.
RGCN Text RGB in user contrast Min.
BIT 5 Y peak limiter 0: Off 1: On
BIT4 OSD ABL 0:Active 1:Inactive
BIT 3.2 ABL start point 00: ABL start point: 0V 01: -0.15V
10:-0.30V 11:-0.45V
ABL
BIT 1.0 ABL gain 00:-0.2V 01:-0.4V
10:-0.6V 11:-0.8V
BIT 7 Blank SW 0: H, V blanking on 1: H, V blanking off
Bit 6
Bit 5.4 OSD level 00: OSD level, 80 IRE 01: 70IRE
10:60IRE 11:50IRE
Bit 3.2 Y gamma 00: Off 01: Y point 90 IRE, Gain –3dB
10:80IRE 11:70IRE
DCBS
Bi t 1.0 Black stretch 00:Off 01:Blackstretchpoint,25IRE
10:35IRE 11:45IRE
BIT 7 Killer off 0: Normal 1: Always killer off
BIT 6 P/N ID 0: PAL/ NTSC killer sensitivity, 1mVpp 1: 10mVpp
CLTO
Chroma data
(TV & not M) BIT5 Cgamma 0:Colorgammaoff 1:On
(continued)
12

SERVICE MANUAL
BIT 4.3 NTSC matrix 00: USA (105 degree) 01: Japan (93 degree)
10: DVD 11:
CLTM
(TV & M)
CLVD(DVD)
CLVO(50hz)
/CLVM（60hz）
(VIDEO)
BIT 2.1.0 Y DL 000: -40 nsec 001: 0 010: 40 nsec 011: 80 nsec
100: 120 nsec 101: 160 nsec 110: 200 nsec 111: 240 nsec
DEF BIT0 = 0: V AGC reference depends on YC VCC; BIT0 = 1: V AGC reference depends on integrated regulator
SECD No use
HPOS 50Hz horizontal phase 00: -3usec 10: 0 1F: +3usec
VP50 V phase (50Hz) 0: V phase delay, 0H 7: 7H
HIT V size 00:-50% 20:0% 3F:50%
HPS Adjusting difference between horizontal centers in PAL and NTSC
VP60 V phase (60Hz) 0:Vphasedelay,0H 7:7H
HITS Adjusting difference between vertical amplitudes in PAL and NTSC
VLIN V-linearity 0:-15% 8:0% F:15%
VSC V-S correction 0:-16% 8:0% F:16%
VLIS Adjusting difference between vertical linear in PAL and NTSC
VSS Correction for shift data of 50 Hz/ 60 Hz
DPC EW parabola 00: 0Vpp 20: 1.4Vpp 3F: 2.8Vpp
DPCS Shift data of EW parabola
HIT69 Vertical amplitude in 16:9 mode (PAL)
DPC69 EW parabola 16:9 in 16:9 mode (PAL)
HIT69S Vertical amplitude in 16:9 mode (NTSC)
DPC69S EW parabola 16:9 in 16:9 mode (NTSC)
KEY Trapezium 00: -13% 20: 0% 3F: 13%
KEYS Shift data of trapezium
WID H size 00: 1.5V V20: 4V 3F: 6.5V
WIDS Shift data of H size
ECCT EW corner top 00: -1.5V 10: 0V 1F: 1.5V
ECCB EW corner bottom 00: -1.5V 10: 0V 1F: 1.5V
VEHT V EHT gain 0:0% 4:5% 7:10%
HEHT H EHT gain 0:0% 4:5% 7:10%
SBY Use in SECAM
SRY Use in SECAM
BRTS Sub brightness (difference)
RFAGC RF AGC 00: IF mute 01: 65dBu 3F: 100dBu
(continued)
13

SERVICE MANUAL
BIT 3.2 AFC gain
(in VIDEO mode)
Data Description
Blanking Period Picture Period
0 0 3 1
0 1 4/7 2/7
1 0 4/3 1
1 1 Off Off
BIT 1.0
HAFC
AFC gain
(in TV mode)
Data Description
Blanking Period Picture Period
0 0 3 1
0 1 4/7 2/7
1 0 4/3 1
1 1 Off Off
V01 Volume output data at 1%
V25 Volume output data at 25%
V50 Volume output data at 50%
V100 Volume output data at 100%
Woofer TA1343 woofer Max.
STAT No use
BIT 7 Readjust VCO when selecting position 0: Enable 1: Disable
BIT 2 N buzz cancel 0: Nyquist buzz cancel, on 1: Off
BIT 1 AFT window SW 0: Wide (-/+ 250kHz) AFT sensitivity, for channel search
1: Narrow (83kHz) For normal operation
FLG0
BIT 0 Over modulation 0: Normal 1: PIF over modulation switch on
BIT 5 MIX GAIN 0: SIF 1MHz convert gain, low gain 1: High gain
FLG1 BIT 4 Sync separation. 0: Sync separation level 40% 1: 36%
REFP AKB pulse position 000: 0H 001: 1H 010: 2H 011: 3H
100: 4H 101: 5H 110: 6H 111: 7H
RSNS R SENSE 00: x 0 20: x 0.5 3F: x 1.0
GSNS G SENSE 00: x 0 20: x 0.5 3F: x 1.0
BSNS B SENSE 00: x 0 20: x 0.5 3F: x 1.0
Bit 6.5.4 PIF FREQUENCY 001: 45.75 MHz 011: 38.9 MHz 100: 38.0 MHz
MOD Bit 1.0 AKB MODE 00: AKB off 01: ACB (cutoff: align to targets)
10: ADB (drive: align to targets) 11: AKB (cutoff/drive: align to targets)
BIT 3.2 VCD STANDBY 00:Normal 01:Normal
10: Normal 11: VCD Standby
STBY BIT 1.0 IF Standby 00:Normal 01:Normal
10: Normal 11: IF Standby
SVM BIT.4 1:co max=1（-0.65 to +0.85）0:comax=0（cutoff range:
-0.65 to +0.65)
SVM1 Data when SVM off
SVM3 Data when SVM on
BIT 3.2 V blanking stop point 00: 310H(50hz) 263H(60hz) 01: 299H(50hz) 254H(60hz)
10: 295H(50hz) 250H(60hz) 11: 291H(50hz) 246H(60hz)
VBLK BIT 1.0 V blanking start point 00: 23H(50hz) 22H(60hz) 01: 33H (50hz)30H(60hz)
10: 37H (50hz)34H(60hz) 11: 41H(50hz) 38H(60hz)
VCEN Vertical centering 00: -32% 20: 0% 3F: 30%
BIT 1.0 Internal ADC 00: GND 01: R output
10: B output 11: Monitor RF AGC via ADC
UCOM BIT5.4.3 Improving NTSC color signal-to-noise
ratio
Available range: 000….011
(continued)
14

SERVICE MANUAL
VTST No use
PYNX Normal H.SYNC Max. 0-----------3F
PYNN Normal H.SYNC Min. 0-----------3F
PYXS ASM/Search H.SYNC Max. 0-----------3F
PYNS ASM/Search H.SYNC Min 0-----------3F
BASC Bass volume Center
BASX Bass volume Max.
TREC Treble volume Center
BALC Balance volume Center
BAS1 Bass in MUSIC mode setting
TRE1 Treble in MUSIC mode setting
WFL1 Woofer in MUSIC mode setting
BAS2 Bass in NEWS mode setting
TRE2 Treble in NEWS mode setting
WFL2 Woofer in NEWS mode setting
BAS3 Bass in THEATRE mode setting
TRE3 Treble in THEATRE mode setting
WFL3 Woofer in THEATRE mode setting
WON1 TA1343 Max. woofer setting. The bigger the setting the smaller Max. woofer.
WON2 Woofer linear setting
NVOL Prescale NICAM
NICL NICAM->MONO level
NICH MONO->NICAM level
BIT 2 AFC gain data setting in TV mode: 1: Adjust AFC gain in the lowest two bits of HAFC 0: With weak signal
received, AFC gain = 0x10; with strong signal received, AFC gain = 0x00
NOIS BIT 7-BIT 0 Criterion of signal strength: >NOIS: Weak signal
<= NOIS: Strong signal
VATT Audio ATT 00:-85DB or less 7F:0DB (7 BITS)
BIT 3 Pedestal clip 0: On 1: Off
COM1
(TC90A49) BIT 2.1.0 VENH2.1.0 000: 0db(x1) …… 111: 3.52db(x1.5)
BIT 7.6.5.4 Set vertical enhancer non-linear point 0000: 4LSB …… 1111: 64LSB
BIT 3 Set Y output horizontal peaking gain 0: 1.5dB 1: 3.0dB
BIT2 Set Y output horizontal peaking on/off 0: On 1: Off
COM2
(TC90A49)
BIT 1.0 Set vertical enhancer coring level 00: 0LSB …… 11: 3LSB
B1(12345) NICAM chip five-equalizer data when the sound mode set to MUSIC:
B11 (for 120Hz) B12 (for 500 Hz) B13 (for 1.5KHz) B14 (for 5KHz) B15 (for 10KHz)
B2(12345) NICAM chip five-equalizer data when the sound mode set to NEWS:
B21 (for 120Hz) B22 (for 500 Hz) B23 (for 1.5KHz) B24 (for 5KHz) B25 (for 10KHz)
B3(12345) NICAM chip five-equalizer data when the sound mode set to THEATRE:
B31(for 120Hz) B32 (for 500 Hz) B33 (for 1.5KHz) B34 (for 5KHz) B35 (for 10KHz)
BBE Highest four bits：BBE contour (0dB to 15dB); Lowest four bits: BBE process (0dB to 15dB)
OSDF OSD frequency setting
15

SERVICE MANUAL
6.3 Adjustments and Bus data
Table 4
Item Data Item Data Item Data Item Data
* MODE0 A6 CNTC 40 # HITS 04 GSNS 00
* MODE1 35 CNTN 08 # VLIN 0C BSNS 00
* MODE2 5D BRTX 20 # VSC 06 MOD 40
* MODE3 00 BRTN 20 # VLIS 00 STBY 00
* MODE4 20 COLX 20 # VSS 01 SVM 00
LANG-OPT 09 COLN 00 # HIT69 14 SVM1 00
LANG-OUT 03 TNTX 28 # DPC69 10 SVM3 06
COM1 04 TNTN 28 # DPC69 18 VBLK 00
COM2 3F ST3 30 # KEY 22 # VCEN 20
BBE 9B SV3 30 # WID 16 UCOM 00
C-MT 99 ST4 28 # HIT69S 01 VTST 00
C-MTB 44 SV4 30 # DPC69S 01 PYNX 2E
C-MB F9 SVD 30 # DPCS 03 PYNN 18
C-MBB 36 ASSH 07 # KEYS 00 PYXS 22
C-N 9E SHPX 10 # WIDS 02 PYNS 1E
C-NB 36 SHPN 10 # ECCT 08 BASC 40
OSDF 70 TXCX 3F # ECCB 08 BASX 70
# OSD 30 RGCN 1F VEHT 04 TEEC 40
* OPT 00 ABL 21 HEHT 01 BALC 40
# RCUT 30 DCBS 16 # SBY 08 BAS1 3C
# GCUT 30 CLTO 3F # SRY 08 TRE1 40
# BCUT 30 CLTS 30 # BRTS 17 WFL1 46
# GDRV 40 * CLTM 23 # RAGC 18 BAS2 20
# BDRV 40 CLVO 3F HAFC 08 TRE2 50
CNTX 7F * CLVM 20 * V01 25 WFL2 00
BRTC 40 CLVD 30 * V25 3A BAS3 20
COLC 28 DEF 01 * V50 4A TRE3 40
TNTC 30 AKB 00 * V100 7F WFL3 20
(continued)
16

SERVICE MANUAL
TNTCAV 48 SECD 08 * WOOFER 72 * WON1 00
COLP 00 # HPOS 0B STST 00 WON2 00
COLS 40 # VP50 04 FLG0 06 NOIS 01
DCOL 40 # HIT 15 FLG1 18 VATT 5D
SCOL 00 # HPS 03 REFP 00
SCNT 09 # VP60 02 RSNS 00
Notes:
①The data sheet may differ dependent on different models.
②The data sheet may differ dependent on different CRTs for the same model.
③The data marked with “*”can be adjusted.
17

SERVICE MANUAL
STRUCTURE AND CHASSIS FUNCTION DESCRIPTION
1. STRUCTURE BLOCK DIAGRAM
Circuit for Buttons on the TV Remote Sensor
Remote Control
R Speaker
L
Sound Power Amplifier TDA8944J (N603)
Speaker
Second Sound Tra
p
VIDEO R L
Side AV
Switch
Y/C Audio
TV/Video S witch
TC90L01N (N901)
AV Output
S AV1 AV2
Power Circuit STR-G8 656 (N801)
Degau Circuit
ssing
150-250v
A
C 50Hz
Interferen
oce-pro
Circuit
f
5V-1 9V-1 16VB 16VC 16VH 135V
CRT
Video Amplifier Q901-906
Vertical Out put LA78041
VM
EEPROM AT24C16 (N230)
2 IN1 IC
Small Signal Processor &MCU
CH08T0605 (TMPA8827PSNG)
(N210)
HV
FV SV
FBT T401
Horizon
ut
tal
Outp V405
Li ene Driv
V404
ABL
VM Amplifier V202
To VM Coil
VM
Processing
Circuit
IF
Preamplifier
V101
SAW Filter
Tuner
TDQ-5B -6M
Fig. 5 Structure Block Diagram of CN -18ED Chassis
18