Changhong Electric PF29T18, 34T18, CPF29T99 Service Manual
FILE NO. SM-CTV-O-123
COLOR TELEVISION
MODEL NO. PF29T18/34T18
/ CPF29T99
CHASSIS NO. CH-20
Please read this manual carefully before service.
SERVICE MANUAL
TABLE OF CONTENTS
SAFETY INSTRUCTIONS......................................................................................1
ADJUSTMENTS..................................................................................................... 4
STRUCTURE AND CHASSIS FUNCTION DESCRIPTION ................................... 17
SERVICE DATA ................................................................................................... 17
REPLACEMENT OF PARTS.................................................................................. 55
APPENDIX 1. CIRCUIT DIAGRAMS
2. PRINTED CIRCUIT BOARD LAYOUTS
3. FINAL ASSEMBLY DIAGRAMS
4. FINAL WIRING DIAGRAMS
SERVICE MANUAL
1
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.
SERVICE MANUAL
2
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
SERVICE MANUAL
3
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.
SERVICE MANUAL
4
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:
① The purity/convergence magnet assembly and rubber wedges need mechanical
positioning. Refer to Fig1, 2.
② For 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.
SERVICE MANUAL
5
Yok
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.
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 I
2
C bus control, change
SERVICE MANUAL
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the bus data to adjust white balance.
Fig. 2
4-pole Magnet Movement 6-pole Magnet Movement
Center Convergence by Convergence Magnets
Incline the Yoke Up (or Down) Incline the Yoke Right (or Left)
Circumference Convergence by DEF Yoke
Fig.3
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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 I
2
C 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 table 1
Table 1
T est Point Voltage (V)
One Pin of L807
145V±1.5V
Positive of C834
12V±1V
Positive of C837
12V±1V
Positive of C832
16V±1V
One Pin of L806
16V±1.5V
Positive of C839
3.3±0.3V
Positive of VD822
3.9±0.3V
Positive of C429
195V±5V
Positive of C436A
48V±3V
(Continued)
SERVICE MANUAL
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Positive of C434
13.5V±1V
Positive of C840
8V±0.5V
One Pin of 326
12V±1V
Positive of C424
5V±0.5V
Heater 6.3V±0.3Vrms
CRT anode voltages
29KV±1.5KV (For 29” CRT)
31.0KV±1.5KV (For 34” CRT)
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 (220V ~, 50Hz) and turn on the TV. Set the brightness and contrast 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 Limited EHT voltage Remarks
29KV±1.5KV 33KV for 29" CRT
31.0KV±1.5KV 35KV for 34" CRT
Note: The data sheet may differ dependent on different CRTs.
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.
Before Adjusting After Adjusting
Fig. 4
SERVICE MANUAL
9
S
5. SERVICE mode
5.1 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,
press the POWER button to quit the S mode.
(“S”is red and other items are yellow.)
Use the ↓/↑buttons on the remote control to highlight an adjustment and the ←/→ buttons
to adjust it.
5.2
Bus data
Table 2 Bus data
Item Adjustment Description
VX00 19 4:3
VX50 01 16:9
VX99 38 ZOOM
5VS/6VS Set to the optimal mode Half vertical center for 50/60Hz
5VA/6VA Set to the optimal mode Vertical amplitude for 50/60Hz
5SC/6SC Set to the optimal mode Vertical S correction for 50/60Hz
5VSH/6VSH Set to the optimal mode Vertical center for 50/60Hz
5VOF/6VOF Set to the optimal mode Character position for 50/60Hz
5HP/6HP Set to the optimal mode Parallelogram correction for 50/60Hz
5HB/6HB Set to the optimal mode Curve correction for 50/60Hz
5HSH/6HSH Set to the optimal mode Horizontal center for 50/60Hz
5HA/6HA Set to the optimal mode Horizontal amplitude for 50/60Hz
5EW/6EW Set to the optimal mode Pincushion and barrel correction for 50/60Hz
5UCR/6UCR Set to the optimal mode Upper corner correction for 50/60Hz
5LCR/6LCR Set to the optimal mode Lower corner correction for 50/60Hz
5TC/6TC Set to the optimal mode Trapezoidal correction for 50/60Hz
RCUT White balance adjustment Red gun cutoff voltage
GCUT White balance adjustment Green gun cutoff voltage
RDRV Dark balance adjustment Red gun drive voltage
GDRV Dark balance adjustment Green gun drive voltage
BDRV 20 Blue gun drive voltage
YDFP 8 PAL brightness delay time
YDFN 2 NTSC brightness delay time
YDFS 2 SECAM brightness delay time
(Continued)
SERVICE MANUAL
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RAGC Set to the optimal mode AGC adjustment（19—1E recommended）
VOL 29 AV output volume control for TDA7442
WBF 30
WBR 30
SOC 1 PWL clip level（5%）
PWL 8 White peak limit
IFO 32 IF phase lock
PEAK 2
BLS 0 Blue extension
BKS 1 Black stretch
CON100 23
CON50 0D
Sub contrast
BRI100 32
BRI50 20
Sub brightness
COL100 3F Sub color
SHP100 3B
SHP50 1C
Sub sharpness
VMDL 03 VM delay
VMAM 03 VM amplitude
COR 3
WS 0 White stretch setting
HDOL 0B Cathode drive level
AGCS 1 AGC speed
VG2B 24 Brightness setting when adjusting G2
VENH 03 Vertical enhance
CBNR 03 Comb noise reduce
TRE1 64
TRE2 32
Treble linearity
BAS1 64
BAS2 32
Bass linearity
VOLA 40/53 MSP3410G/TDA7442
VOLB 46/58 MSP3410G/TDA7442
VOLC 4B/60 MSP3410G/TDA7442
VOLD 51/63 MSP3410G/TDA7442
LOUD 20 Loudness (not for TDA7442)
SC1 74 SCART1 PRESCAL (not for TDA7442)
SC2 74 SCART2 PRESCAL (not for TDA7442)
SCIN 1E SCART IN PRESCAL (not for TDA7442)
FMIN 13 FM frequency bias setting (not for TDA7442)
NNIN 5A NICAM setting (not for TDA7442)
(Continued)
SERVICE MANUAL
11
WOCF 1E ( not for TDA7442)
MEFF 44
MAMP FF
MHAR 64
MLOP 19
MHIP 05
MDB setting (not for TDA7442)
OP1
F8 (For PF29T18/34t18 only)
D8 (For CPF29T99 only)
Option set byte 1
OP2 20 Option set byte 2
OP3 0C Option set byte 3
OP4 11 Option set byte 4
OP5 88 Option set byte 5
OP6 0F Option set byte 6
OP7 08 Option set byte 7
Notes:
① The data sheet may differ dependent on different models.
② The data sheet may differ dependent on different CRTs for the same model.
③ Designs and specifications are subject to change without notice.
Table 3 Option bit setting
Bit Item Description
0 OP_NICAM 1: MSP3410；0: TDA7442
1 OP_COMB 1: Yes; 0: No
2 OP_SVM 1: Yes; 0: No
3 OP_AV2 1: Yes; 0: No
4 OP_FAV 1: Yes; 0: No
5 OP_FAVS 1: Yes; 0: No
6 OP_STORE
0: West Europe
1: East Europe
OP1
7 OP_OSO 1
0 OP_AVC
1: MSP3410;
0: TDA7442
1 OP_MDB
1: MSP3410;
0: TDA7442
2
3
4
Text setting
000: West Europe text
001: East Europe text
010: Ukrainian text
100: Russian text
110: Greek text
OP2
5 OP_ PARENT 1 (Child lock)
(Continued)
SERVICE MANUAL
12
6 OP_TILT Tilt correction
7 OP_FSL 0
0 OP_BSCREEN
1: Black screen available when changing
channels;
0: Black screen not available when changing
channels
1 OP_5060 0
2 OP_DK 1: D/K option
3 OP_BG 1: B/G option
4 OP_I 1: I option
5 OP_L 1: L option
6 OP_AUTO_SOUND 1: MSP3410；0: TDA7442
OP3
7 OP_EQUAL 1: MSP3410；0: TDA7442
0 OP_FMWS 1
1 OP_POWER
1: Memory on
0: Soft on
2 OP_COUNTRY 1: COUNTRY display option
3 OP_LOGO 0: LOGO display not available
4 OP_DFL 1
5 OP_BLUE_BACK
0: Blue back not available under no signal
condition;
1: Blue back available under no signal
condition
6 OP_ACI 1: Yes; 0: No
OP4
7 OP_ATS 1: Yes; 0: No
0 OP_LANG0 0
1 OP_LANG1 0
2 OP_LANG2 0
3 OP_LANG3 0
4 OP_SOUND0 0
5 OP_SOUND1 0
6 OP_SOUND2 1
OP5
7 OP_STRIKE 1
0 OP_MUTE 1
1 OP_TUNER 1: West Europe 0: BG
2 OP_AFT 1
3 OP_ENGLISH 1
4 OP_FRANCE 1
5 OP_GERMAN 1
6 OP_SPAIN 1
OP6
7 OP_DANMARK 1
(Continued)
SERVICE MANUAL
13
0 OP_HOLAND 1
1 OP_SUOMI 1
2 OP_GREECE 1
3 OP_ITALY 1
4 OP_NORWAY 1
5 OP_PORTUAL 1
6 OP_SWEDEN 1
OP7
7 OP_TURKY 1
Note :
① Bit6, Bit5, Bit4 in OP5 are outgoing audio option settings as follows: 000: East Europe
(D/K); 001: West Europe (B/G); 010: UK (I); 110: France (L); 100: Europe (Auto).
② Bit3, Bit2, Bit1 and Bit0 in OP5 are outgoing language option settings as follows:
English, French, German, Spanish, Danish, Dutch, Finnish, Greek, Italian, Norwegian,
Portuguese, Swedish and Turkish successively begun with.
Tuner
A001
Small Signal Processor &
Microcontroller
(UOC)
TDA9594 (N101)
Video Amplifier
TDA6108JF
Comb Filter
TC90A49
(N501)
Remote Sensor
Circuit for Buttons
IIC
Y/C
Video Switch
HEF4052 (N302)
R/G/B
CRT
AGC
IIC
IF Pre-
amplifier
V002
SAW Filter
K3953M (Z003)
SAW Filter
K9656M (Z002)
VIF
SIF
EEPROM
AT24C16 (N102)
Line Drive
Including
V402,T401
SCART Jack 1
SCART Jack 2
Side
AV In
S- Video In
Video Switch
HEF4052
(N301)
Trap
Sound Power
Amplifier
TDA8944J (N603)
Speakers
Audio Processor TDA7442 (N602)
+5V
Filament
Vertical Output
TDA8359 (N401)
Horizontal
Output V404
FBT
T402
ABL Circuit
HV
FV
SV
+200V
+14V
Voltage
E-W
V-out+
H-out
IIC
Power Circuit
STR-W6856
(N801)
+15V-1
+12V
+145V
+3.3V
+3.9V
220-240V AC
50/60Hz
+15V-2
38
48
42
R/G/B Input
IFO
TV-CVBS
CVBS 2
AV-CVBS
CVBS 1 In
Y/C
AV-CVBS
Y/C
R/L1 In
R/L3 In
R/L2 In
R/L2 Out
Main
R/L
47
40
Audio Out
V-out-
EHT Circuit
R/L1 Out
67,68
73,78
CTRL SIG
CTRL SIG
SVM Circuit
SVM
To VM Coil
+45V
+12V-2
Audio Out
V2 Out
V1 Out
+8V
SERVICE MANUAL
14
Fig.5 Structure Block Diagram for CH-20 Chassis
STRUCTURE AND CHASSIS FUNCTION DESCRIPTION
1. Structure Block Diagram
SERVICE MANUAL
15
Fig.6 Block Diagram for Supply Voltage System for CH-20 Chassis
2. Block Diagram for Supply Voltage System
Degaussing
Circuit
Bridge Rectifier
VD801-VD804,C803,
C804,C807,C808
Switch Transformer BCK-24339L
Feedback
Circuit N801
Interference-proof
Circuit
+15V-2
+145V
FBT T402
+14V
+45V
+200V
HV
FV
SV
Filament
Voltage
IF Amplifier
V002
Power Regulation
and Control
STR-W6856
(N801)
220-240V
AC
50/60Hz
Vertical Output
TDA8359 (N401)
Sound Power
Amplifier
TDA8944J
(N603)
VD414
VD411
VD412
Video Amplifier
TDA6108JF
+8V
+5V
Regulator
V405
UOC
TDA9594 (N101)
VD819
VD815
Audio Processor
TDA7442 (N602)
Audio Out Amplifier
V303,V304,V310,V311
Video Out Amp-
lifier V301,V302
Y/C Amplifier
V505-V510
ABL & EHT
Circuit
CRT RGB Board
Tuner
A001
Comb Filter
TC90A49
Video Switch
HEF4052
Control Signal Driver
Circuit Including KAV, etc.
VD816
+15V-1
Line Drive
Circuit
VD818
+3.3V
VD820
UOC
TDA9594 (N101)
LED
Circuit
Remote Sensor
Hs0038
Circuit for
Buttons
EEPROM
AT24C16 (N102)
+12V-1
VD817
Fl501 HFD2-CL2-M
+3.9V
Regulator
V806
Bus Data
Driver Circuit
UOC
TDA9594 (N101)
V808
Tuner
A001
Regulator
VD003
+33V
VD410
+12V-2
VD816
SERVICE MANUAL
16
3. Chassis Description
General Description
CH-20 chassis is applied in CPF29T99/PF29T18/34T18, which mainly uses Philips’ advanced
UOC-ultimate one chip TDA959X and I
2
C-bus controlled IC. With combination of
microcontroller and small signal processor, the TDA959X features high-integrity,
high-performance-to-price ratio and high-reliability and advanced functions with fewer external
components, which provide much more convenience for manufacturing and technical service.
In addition, TDA959X is good in geometric distortion, more suitable for pure flat TV sets.
The following features are available in the chassis:
RF color systems: PAL/SECAM
Video systems: PAL/SECAM/NTSC
Sound systems: D/K B/G I H L L1
100 programs preset
I
2
C bus control
Audio output: Main channel: 7W+7W (distortionless) (THD 7%)
Selectable sound modes: Music, Theatre, Speech, Personal
Selectable picture modes: Personal, Rich, Natural, Soft
AV stereo + audio processing ( M S P 3 4 X X o r T D A 7442)
PAL/NTSC 3-line comb filter
Earphone output
Selectable aspect ratio: 4:3, 16:9, Zoom
Auto identification and changeover of vertical frequency 50/60Hz
Auto identification of SCART picture input format (4:3,16:9)
Auto identification of SCART1 signal source input (RGB/CVBS)
The chassis mainly uses the following ICs and assemblies.
Table 4 Key ICs and Assemblies
Serial No. Position Type Function Description
1 N101 TDA9594H Microcontroller and small signal processor (UOC)
2 N102 AT24C16 EEPROM
3 N602 TDA7442 Audio processor
4 N603 TDA8944J Sound power amplifier
5 NY01 TDA6107JF /TDA6108JF Video amplifier
6 N501 TC90A49P COMB Filter
7 N301/N302 HEF4052BP Electronic switch circuit
8 N401 TDA8359J Vertical scan output stage circuit
9 N801 STR-W6856 Power module
10 A001 TDQ-6B3-P/ TAF5-EPB2 Tuner
SERVICE MANUAL
17
SERVICE DATA
1. Technical Data of Key ICs
1.1 Microcontroller and Small Signal Processor TDA959X
(1) General Description
The various versions of the TDA959X H/PS-N1 series combine the functions of a video
processor together with a m-Controller and US Closed Caption decoder. Most versions have
a Teletext decoder on board. The Teletext decoder has an internal RAM memory for 1 or 10
page text. Some versions can generate a ‘Mixed-down’ I-signal for the demodulation of DVB
signals. The ICs are intended to be used in economy television receivers with 110 picture
tubes.
The ICs have supply voltages of 8 V and 3.3 V and they are mounted in an SDIP-64 or QFP
80 envelope.
The features are given in the following feature list. The differences between the various ICs
are given in the table.
(2) Features
TV-signal processor
Available in all versions
● Multi-standard vision IF circuit with alignment-free PLL demodulator
● Internal (switchable) time-constant for the IF-AGC circuit
● Integrated chrominance trap circuit Integrated luminance delay line with adjustable delay
time
● Picture improvement features with peaking (with switchable centre frequency, depeaking,
variable positive/negative overshoot ratio and video dependent coring), dynamic skin tone
control and blue- and black stretching
● Scan Velocity Modulation output
● Integrated chroma band-pass filter with switchable centre frequency
● Only one reference (12 MHz) crystal required for the m-Controller, Teletext- and the colour
decoder
● Multi-standard colour decoder with automatic search system
● Internal base-band delay line
● Indication of the Signal-to-Noise ratio of the incoming CVBS signal
● A linear RGB/YUV/YPBPR input with fast blanking for external RGB/YUV sources. The
synchronization circuit can be connected to the incoming Y signal. The Text/OSD signals are
internally supplied from the m-Controller/Teletext decoder.
● RGB Cathode Calibration’, white point and black level off-set adjustment so that the colour
temperature of the dark and the light parts of the screen can be chosen independently.
● Contrast reduction possibility during mixed-mode of OSD and Text signals
● Adjustable ‘wide blanking’ of the RGB outputs
● Horizontal synchronization with two control loops and alignment-free horizontal oscillator
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