Note:This service manual is only for professional service personnel’s reference. Before
1. SAFETY INSTRUCTION AND GENERAL INSTRUCTION
1.1 X-RAY RADIATION PRECAUTION
1) Excessive high voltage can produce potentially hazardous X-RAY RADIATION. To avoid such
2) Each time a receiver requires servicing, the high voltage should be checked following the HIGH
3) The primary source of X-RAY RADIATION in this TV receiver is the picture tube. For continuous
servicing the unit, please read the following items carefully.
Before servicing and aligning this equipment, please read the following “X-RAY RADIATION
PRECAUTION” , “SAFETY PRECAUTION” and “PRODUCT SAFETY NOTICE”.
hazards, the high voltage must not be above the specified limit. The normal value of the high voltage
of this receiver is below 31.5kV at 1.6A beam current, the high voltage must not, under any
circumstances, exceed 33kV.
VOLTAGE CHECK procedure in this manual. It is recommended the reading of the high voltage be
recorded as a part of service record. It is important to use an accurate and reliable high voltage
meter.
X-RAY RADIATION protection, the replacement tube must be exactly the same type tube as
specified in the parts list.
4) Some parts in this receiver have special safety-related characteristics for X-RAY RADIATION
protection. For continuous safety, parts replacement should be undertaken only after referring to the
PRODUCT SAFETY NOTICE below.
1.2 SAFETY PRECAUTION WARNING:
Service should not be attempted by anyone unfamiliar with the necessary precaution on this receiver.
The following are the necessary precautions to be observed before servicing this chassis.
1) Since the power supply circuit of this receiver is directly connected to the AC power line, an isolation
transformer should be used during any dynamic service to avoid possible shock hazard.
2) Always discharge the picture tube anode to the CRT conductive coating before handling the picture
tube. The picture tube is highly evacuated and if broken, glass fragments will be violently expelled.
Use shatter proof goggles and keep picture tube away from the unprotected body while handling.
3) When replacing a chassis in the cabinet, always be certain that all the protective devices are put
back in place, such as: non-metallic control knobs, insulating covers, shields, isolation
resistor-capacitor network etc.
4) When replacing parts or circuit boards, disconnect the power cord.
5) When replacing a high wattage resistor (oxiode metal film resistor) on the circuit board, keep the
resistor 10mm (1/2in) away from circuit board.
6) Connection wires must be kept away from components with high voltage or high temperature.
7) If any fuse in this TV receiver is blown, replace it with the FUSE specified in the chassis parts list.
1.3 PRODUCT SAFETY NOTICE
Many electrical and mechanical parts in the chassis have special safety-related characteristics. These
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characteristics are often passed unnoticed by a visual inspection and the X-RAY RADIATION protection
afforded by them cannot necessarily be obtained by using replacement components rated for higher
wattage, etc. Replacement parts which have these special safety characteristics are identified in this
manual and its supplement electrical components having such features are shaded on the schematic
diagram and the parts list.
Before replacing any of these components, read the parts list in this manual carefully. The use of
substitute replacement parts which do not have the same characteristics as specified in the parts list
may create shock, fire, X-RAY RADIATION or other hazards.
2 Alignment items and procedure
The alignment flow chart (see below figure).
EEPROM copy
B+ check
Focus adjust and aging
High-handed
Field breadth
and field line
White balance and sub-bright
RF AGC adjust
Audio check
VG2 adjust
H-field and center
field and field breadth
Filament voltage
X-ray protect
Picture and audio
Sub-brightness
White balance
OSD center position
Color pure and assemble
Foucs fine adjust
AV (S.DVD)
The button check
Leave factory state setup
Remote control check
check
Assemble check
Safety check
3 TEST EQUIPMENT
3.1 AUDIO VOLTAMETER
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3.2 OSCILLOGRAPH
3.3 HIGH-VOLTAMETER
3.4 DIGITAL MULTIMETER
3.5 AC ATTACK PULL TEST EQUIPMENT
3.6 SCAN frequency signal generator BT-3
4 Debugging instruction
4.1 enter into the factory debugging menu
use to the remote control(RC-A23),follow to the blow model enter into the factory:
DISPLAY → MUTE → MUTE → MUTE → enter into the factory
press “sleep” button for pages upward, press “return” button for pages downward, press “CH+/-” to
select alignment items and “VOL+/-” to adjust volume, press “MUTE” to exit.
If the remote sensor designed for alignment is unavailable, press the following buttons to enter by
using user remote sensor
4.2 B+ voltage adjustment
Check B+ voltage ( negative pole of VD509) by using DC voltmeter DC 200V of 135V±2.
4.3 AGC adjustment
Measure the voltage of RF AGC by connecting digital DC voltmeter with TP3, receive weak signal
(40dBu) and the static AGC voltage of TP1 AGC should be V1=4V±0.2V; the receive antenna signal
(60dBu), adjust the value of P6 RF. AGC of factory menu and the start-control voltage of TP1 AGC
should be V2=3.5V±0.2.if V2>3.5V, then the voltage is -1 or -2,if V2<3.5V, then the voltage is+1 or+2. the
antenna input 100dBu signal, after the picture should not be appeared no-sync , distortion and moire;
input 35-40dBu weak signal ,it should not be appeared distortion and no-sync and sound abnormity
electrophoresis of it.
4.4 White balance and screen-grid voltage adjustment
After enter P5 of factory menu, use remote sensor directly to adjust white balance by pressing the
following digital buttons:
“1”=R.BIAS(+) “2”=G.BIAS(+) “3”=B.BIAS(+)
“4”=R.BIAS(-) “5”=G.BIAS(-) “6”=B.BIAS(-)
press “p-p” button to select picture mode custom→T1→T2→bright→soft→nature→user→custom will
be display on the screen.
The T1 mode has the maximum value of brightness and contrast with all the other items minum. Value of
all the analog are minimum while in T2 mode.
Before adjustment you should set the following items: SUB-BRIGHT=50, R.B=100, G.B=100, B.B=100,
R.D=100, G.D=15, B.D=100
press “P-P” button to select T2 picture mode, press CH+/- to select LINE, press vol+ to let the field
scanning fail to oscillate, adjust the screen-grid potentiometer on FBT clockwise to let horizontal bright
line just appear on the screen; let the value of G.B unchanged, adjust R-B and B-B to let the horizontal
bright line appear white. If the green horizontal line don’t appear firstly, fine-turn the screen-grid voltage,
green and blue just appear. After adjustment press VOL- to obtain normal field scanning mode.
4.5 Receive signal (A7), enter P6 of factory menu, adjustment SUB-BRIGHT to let picture on the screen
micro-bright.
4.6 receive white balance adjustment signal
enter P5 of factory menu, press PP to select T1 picture mode, let the value of G.D unchange, adjust R.D
and B.D to let the white part of the picture appear “white”.
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4.7 Use white balancer to rectify the white balance under following conditions
color temperature:12000K+8MPCD x =0.270± 0.008 Y=0.283±0.008; dark space: 4.5nit, bright space:
60nit
Note:1. While the colour saturation changed from maximum to minimum, if the dark balance appears
changeable,adjust RY.TV and BY.TV (P12) to let it coincide with white balance.
2. If the dark balance appears changeable while connected with DVD, adjust BY.YUV and RY.YUV
(P12) to let it conincide with white balance.
4.8 line-filed scanning amplitude and linearity and center adjustment and raster correct adjstment.
4.9 receive signal (A28), press the PP button the picture model, set standard adjustment the P1 of
V.SIZE and V.SHIFT and H..PAHSE and V.LINE and VSC, let the P2 coincide with request.
4.10 receive signal (G43), press the PP button the picture model, set standard adjustment the P3 of
V.SIZE and V.SHIFT and H..PAHSE and V.LINE and VSC, let the P4 coincide with request.
4.11 High voltage and filament voltage check
Connect a high-voltage meter between anode cap of picture tube and the ground, measure the filament
voltage using rms voltmeter, set the picture mode to “standard”, the high-voltage: 29KV±1.5KV,filament
voltage: 6.3±0.1Vrms.
4.12 x -ray protection check
Receive local TV signal, set the picture mode to “standard”, shorten the circuit and measure the
value of TP1-TP2, restart the TV 30 seconds after turn off the power source and it should return to
normal.
4.13 AV function check
according to the owner’s manual require, connect to the AV equipment and the AV interface:
VIDEO IN: 1 Vp-p 75OHM AUDIO IN: (-8±3)dBm>47 kOHM
S interface Y IN: 1 Vp-p 75OHM C IN: 0.3 Vp-p 75OHM
DVD Y IN: 1 Vp-p 75OHM Cr IN: 0.7 Vp-p 75OHM
Cb IN: 0.7 Vp-p 75OHM
4.14 AV parts check
incept to standard the TV signal:
a) AV and crossfire and allophone and shake ;
b) The user control function ana picture model
c) The remote control function check;
d) Color pure and converge check.