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Service Manual
59 / 66 Cm STEREO Colour Television
CHASSIS : CP-775


MODEL :2594ST / 2896ST
2898ST / 28G2ST
25G1ST / 29G1ST
Specifications

CRT 25" : A59EAK071X11 (PHILIPS)
28" : A66EAK071X11 (PHILIPS)
System TF : PAL - B/G for West Europe, NTSC-3.58 / 4.43 (Play back)
TA : PAL - B/G, SECAM-L/L' for France, NTSC-3.58 / 4.43 (Play back)
TU : PAL- I for U.K, NTSC-3.58 / 4.43 (Play back)
TK : PAL/SECAM - B/G, D/K, NTSC-3.58/4.43(play back) for East Europe & CIS
Main Voltage 230V AC, 50Hz
Power Consumption Stand-by mode : 10 Watts
Normal operating mode : 25" = 75 Watts
28" = 75 Watts
Sound output 5 + 5 Watts, 10 % THD at RF 60 % mod. (1 )
Speaker 12W 4 ohm x 2 EA
Antenna 75 ohm unbalanced input
Impedance
Tuning system VS( voltage synthesis ) tuning
Tuner 3303KHC (TF, TA, TK, TI Model)
BAND I : CH2 - CH4
BAND III : CH5 - CH12
CABLE BAND : S1' - S3' , S1 - S20
HYPER BAND : S21 - S41
BAND IV, V : CH21 - CH69
DT2-IV17D (TU Model )
BAND IV, V : CH21 - CH69
Number of 70 programs
program
Aux. Terminal 21 pin EURO-SCART jack ( AV input, TV output, RGB input )
21 pin EURO-SCART jack ( AV input, S-VHS input )
RCA type AV input jack
Headphone jack (3.5 mm )
Remote controller R-28B03 or R-35D05 with 2 "AA" type batteries
Teletext 8 pages memory TOP & FLOF
- West option :English, German/Dutch/Flemish, French, Italian,
Spanish/Portuguese, Swedish/Finnish/Danish, Czech/Slovak
- East option : Polish, Czech/Slovak, Rumanian, Hungarian, Servo-croat,
German/Dutch/Flemish, French, Italian
- Turkish option : Turkish, English, German/Dutch/Flemish, French,
Italian, Spanish/Portuguese, Swedish/Finnish/Danish
- Cyrillic option: Russian, Lettish/Lithuanian, Estonian, Ukranian,
Czech/Slovak, Servo-croat, English
OSD language -East,West,Turkish Version : English,French,German,Italian,Spanish
-Cyrillic Version : Russian, English, German



1
21 PIN EURO-SCART

PIN Signal Designation Matching Value
1 Audio Out(linked with 3) 0.5Vrms,lmp<1 (RF 60% MOD)
2 Audio In(linked with 6) 0.5Vrms,lmp>10
3 Audio Out(linked with 1) 0.5Vrms,lmp<1 (RF 60% MOD)
4 Audio Earth
5 Blue Earth
6 Audio in (linked with 2) 0.5Vrms,lmp>10
7 Blue in 0.7Vpp 3 ,lmp75
8 Slow(Function) Switching TV:0-2V,PERI:9.5-12V,lmp>10
9 Green Earth
10 NC
11 Green In 0.7Vpp 3 ,lmp75
12 NC
13 Red Earth
14 NC
15 Red In, C In 0.7Vpp 3 ,lmp75
16 Rapid(Blanking) switching Logic 0:0-0.4V,Logic 1:1-3V,Imp 75
17 Video Earth
18 Rapid Blanking Earth
19 Video Out 1Vpp 3 ,lmp75
20 Video In, Y In 1Vpp 3 ,lmp75
21 Common Earth




20 18 16 14 12 10 8 6 4 2


21 19 17 15 13 11 9 7 5 3 1




2
Safety Instruction

WARNING: Only competent service personnel may carry out work involving the testing or repair of
this equipment.


X-RAY RADIATION PRECAUTION
1. Excessive high voltage can produce potentially 2. The only source of X-RAY Radiation in this TV
hazardous X-RAY RADIATION.To avoid such receiver is the picture tube.For continued X-RAY
hazards, the high voltage must not exceed the RADIATION protection,the replacement tube
specified limit. The nominal value of the high must be exactly the same type tube as specified
voltage of this receiver is 26 at max beam in the parts list.
current. The high voltage must not, under any
circumstances, exceed 29.5 (25"), 30 (28").
Each time a receiver requires servicing, the high
voltage should be checked. It is important to use
an accurate and reliable high voltage meter.




SAFETY PRECAUTION
1. Potentials of high voltage are present when this 2. If any Fuse in this TV receiver is blown, replace it
receiver is operating. Operation of the receiver with the FUSE specified in the Replacement
outside the cabinet or with the back board Parts List.
removed involves a shock hazard from the 3. When replacing a high wattage resistor(oxide
receiver. metal film resistor)in circuit board, keep the
1) Servicing should not be attempted by anyone resistor 10mm away from circuit board.
who is not thoroughly familiar with the 4. Keep wires away from high voltage or high
precautions necessary when working on high- temperature components.
voltage equipment. 5. This receiver must operate under AC230 volts,
2) Discharge the high potential of the picture tube 50Hz. NEVER connect to DC supply or any other
before handling the tube. The picture tube is power or frequency.
highly evacuated and if broken, glass
fragments will be violently expelled.




PRODUCT SAFETY NOTICE
Many electrical and mechanical parts in this have identified by designated symbol on the parts list.
special safety-related characteristics. These Before replacing any of these components, read the
characteristics are often passed unnoticed by a parts list in this manual carefully. The use of
visual inspection and the X-RAY RADIATION substitute replacement parts which do not have the
protection afforded by them cannot necessarily be same safety characteristics as specified in the parts
obtained by using replacement components rated list may create X-RAY Radiation.
for higher voltage,wattage,etc. Replacement parts
which have these special safety characteristics are
identified in this manual and its supplements,
electrical components having such features are




3
Alignment Instructions

1. AFT

1.1 Standard B/G,D/K,I and L
1) Set a Signal Generator with
- RF FREQUENCY = 38.9 MHz,
- RF OUTPUT LEVEL = 80 5 dBuV
- System = PAL / SECAM - B/G, D/K, I
2) Connect the Signal Generator RF Output to P101 (Tuner IF Output).
There must be no signal input to the tuner.
3) Press the "AFT" KEY and wait until the TV screen display "AFT OK".

1.2 Standard SECAM-L' (France VHF-Low)
Above mentioned "1.1" adjustment has to be done in advance.
1) Set a Signal Generator with
- RF FREQUENCY = 34.5 MHz,
- RF OUTPUT LEVEL = 80 5 dBuV
- System = SECAM - L'
2) Connect the Signal Generator RF Output to P101 (Tuner IF Output).
There must be no signal input to the tuner.
3) Press the "L' AFT" KEY and wait until the TV screen display "L AFT OK".

2. AGC
1) Set a Pattern Generator with RF LEVEL 63 2 dBuV .
2) Connect a OSCILLOSCOPE PROBE to P101 (TUNER AGC INPUT).
3) Adjust AGC UP/DOWN KEY the voltage drop 1V dc over below its maximum voltage.

Alternative Method
1) Set a Pattern Generator with
- RF LEVEL 80 5 dBuV
- PAL CROSSHATCH
( without SOUND CARRIER )
2) Connect a OSCILLOSCOPE
( Bandwidth 100MHz ) PROBE
to P101 (TUNER IF OUTPUT).
3) Use AGC UP/DOWN KEY to obtain
an envelop amplitude 200 + 50 mVp-p.

3. SCREEN
1) Apply a COLOR BAR pattern signal.
2) Set the CONTRAST, BRIGHTNESS Black level
to MAX, COLOR to MIN.
3) Set the R,G,B LEVEL to CENTER (31/63) 140 5Vdc
with R,G,B UP/DOWN KEY.
4) Connect a OSCILLOSCOPE PROBE
to P906 ( CRT CATHOD R, G, B ).
5) Adjust the SCREEN VOLUME on FBT
such that the highest black level voltage GND
140 5Vdc.




5
4. WHITE BALANCE
1) Set the TV to NOR I mode.
2) Set the R,G,B LEVEL to CENTER with R,G,B UP/DOWN KEY .
3) Adjust the R,G,B UP/DOWN KEY of the other color which did not appear
on the screen to obtain WHITE.

5. FOCUS
1) Apply a RETMA PATTERN signal.
2) Adjust the FOCUS VOLUME on FBT to obtain optimal resolution.

6. GEOMETRY

6.1 VERTICAL CENTER
1) Set the TV to NOR I mode.
2) Pressing the V-SIZE UP/DOWN KEY, the
lower half of the screen is blanked.
3) Adjust the border line of blanked picture
coincident with the mechanical center marks
of the CRT using the V-SIZE UP/DOWN KEY.


6.2 VERTICAL SIZE
The VERTICAL CENTER adjustment
has to be done in advance.
1) Apply a RETMA PATTERN signal.
2) Set the TV to NOR I mode.
3) Adjust the upper part of the picture
with the V-SIZE UP/DOWN keys.


6.3 VERTICAL SLOPE
The VERTICAL SIZE adjustment
has to be done in advance.
1) Apply a RETMA PATTERN signal.
2) Adjust the lower part of the picture
with the V-SLOPE UP/DOWN keys.


6.4 VERTICAL S-CORRECTION
1) Apply a CROSSHATCH PATTERN signal.
2) Adjust the S-COR UP/DOWN KEY to obtain
the same distance between horizontal lines.


6.5 HORIZONTAL CENTER
1) Apply a RETMA PATTERN signal.
2) Adjust picture centering with CENTER
LEFT/RIGHT keys.




6
7. EW

7.1 WIDTH
1) Apply a RETMA PATTERN signal.
2) Pressing the EW KEY, the WIDTH OSD appear in the screen.
3) Adjust the over to make a perfect circle with VOL-UP/DOWN KEY.




7.2 PARA
1) Apply a CROSSHATCH PATTERN signal.
2) Pressing the EW KEY, the PARA OSD appear in the screen.
3) Adjust the vertical line to straight with VOL-UP/DOWN KEY.




7.3 CORNER
1) Apply a CROSSHATCH PATTERN signal.
2) Pressing the EW KEY, the CORNER OSD appear in the screen.
3) Adjust the vertical line to straight with VOL-UP/DOWN KEY.




7.4 TRAPI
1) Apply a CROSSHATCH PATTERN signal.
2) Pressing the EW KEY, the TRAPI OSD appear in the screen.
3) Adjust the vertical line to straight with VOL-UP/DOWN KEY.




7
If EEPROM (I702) has been changed ;
- Option data has to be changed and
- all alignment function has to be readjusted .




The initial state of adjustment are as follows; Service Remocon


28TAF 28TUF 28TFF
POWER
TUNER 3303KHC DT21V17D 3303KHC
N O R M AL EW
OPT
LANGAGE French English English SVC ION


W/B RGB = 32 32 32
PR

AGC 11 9 10 VOL VOL
PR

V-CENTER 30 37 30 SEARCH
EFFECT TREBLE
STOP

V-SIZE 52 54 52 MIN MAX
MODE BASS
V-SLOPE 27 28 27
RCH



MIN MAX
SEA




WOOFER BAL
S-COR 15 15 15
L R
H-CENTER 43 42 42
TEM




MAX MAX MAX
SY S




WIDTH 63 63 62
SE T




CONT BRI COL
CH




MIN MIN MIN
PARA 36 38 37

CORNER 30 28 30 AUTO
AFT AFT-L' TEST AV TTX

TRAPI 29 28 29
+ + + + +

V- CENTER V- SIZE V- SLOPE S-COR. SUB BRI.

- - - -


H-CENTER
+ + + L R

R G B
AGC
- - - +

R-30SVC




REMOTE CONTROLLER R-30SVC




8
SIF ADJUSTMENT
1. APPARATUS CONNECTION & PRESETTING
* CONNECTION * PRESET
1) Connect H-out of LSW-480 to X-axis of the 1) Oscilloscope Scaling
oscilloscope and V-out of LSW-480 to Y-axis a) Put the scale of X and Y of the oscilloscope
of the oscilloscope. to D.C. level
2) Connect the sweep signal output to TP1. b) Set the horizontal time display to X-Y.
3) Set ATTENUATOR of LSW-480 to 20dB. c) Put the horizontal axis (x) to 1V / div. and the
4) Supply 12V D.C. voltage(B+) to TP3. vertical axis (Y) to 2V / div.
5) Supply 3V D.C. voltage(B+) to TP4. 2) LSW-480 MARKER FREQ. SETTING
6) Connect the test point of LSW-480 to TP2.
fp(n+1) fs fc fp-2 fp fs(n-1)
7) Adjust L109(AFT COIL) so that the P marker
31.9 33.4 34.47 36.9 38.9 40.4
point is located on the reference level.




PIF SWEEP MAKER (LSW-480) OSCILLOSCOPE

GENERATOR
H-OUTPUT X
V-OUTPUT Y
OUTPUT
FROM TP




TP1 (TUNER IF) TP2 (I603 #12)

TP3 (TUNER B+) TP3 (I603 #3)




DC POWER SUPPLY DC POWER SUPPLY
(+12V) (+3V)




- Connection For SIF Adjustment -




Y


X
P
(38.9 MHZ)




9
IC Description

DW5255S*(Micro-controller & West/East Teletext Decoder)
(1) General Description
The TDA5255 contains a slicer for VPS and TTX, an accelerating acquisition hardware module, a display
generator for "LEVEL 1" TTX data and a 8 bit u-controller running at 333 nsec cycle time.
The controller with dedicated hardware guarantees flexibility, does most of the internal processing of TTX
acquisition , transfers data to/from the external memory interface and receives/transmits data via I2C and
UART user interfaces.
The Slicer combined with dedicated hardware stores TTX data in a VBI 1Kbyte buffer.
The u-controller firmware does the total acquisition task ( hamming- and parity -checks,
page search and evaluation of header control bits) once per field.

(2) Feature