Safety instruction………………………………………………………………………1
General instruction……………………………… ……………………………………… .1
Alignment instruction……………………………………………………………………2
Alignment flow ..……………………………………………………………………..2
Alignment method…………………………………………………………………..3
BLOCK DIAGRAM………………………………………………………………………... 8
MAIN IC……………………………………………………………………………….. 9
Electrical parts list………………………………………………………………13
Exploded view…………………….……………………………………………….51
Schematic diagram………………………………………………………………….60
Note: This service manual is only for professional service personnel’s reference. Before
servicing the unit, please read the following items carefully.
1 safety instruction
1.1 X-RAY radiation precaution
1.1.1 Excessive voltage will cause harmful X-ray. To avoid this radiation hazard, the high voltage should
fall within the limitation. The appliance works at AC 120V, 60Hz. The high voltage of zero beam current
should be within 29.0kV on condition that the main power (B+) voltage is AC135V. And it should not
exceed 30kV in any condition.
* Keep the main power voltage at 135V when checking the high voltage.
1.1.2 The primary source of X-RAY RADIATION is the CRT. The CRT of this TV set have gotten the
approval of safety authenticat ion i nspect ion. The rep lacem ent CR T should be exactly the same type and
specification CRT which has gotten a similar safety approval, and check the high voltage according to
the HIGH VOLTAGE CHECK procedure.
1.2 safety precaution
a. Since the power supply circuit of this receiver is directly connected to the AC power line, an isolation
transformer is necessary during dynamic service to avoid possible shock hazard.
b. Always discharge the graphite layer conductor when moving the CRT.
c. Disconnect the power cord before replacing parts.
d. When replacing high-power resistor, keep the resistor 10 mm away from the circuit board.
1.3 Component safety precaution
Many electrical and mechanical parts in the chassis have special safety-related characteristics. These
characteristics are often passed unnoticed by a visual inspection. Replacement parts which have these
special safety characteristics are identified in this manual and its supplement electrical components
having such features are shaded or marked by on the schematic diagram and the parts list. Before
replacing any of these components, read the parts list in this m anual carefully. The use of substitute
replacement parts which do not have the same characteristic as specified in the parts list may create
shock, fire, X-RAY RADIA TI O N or other hazards.
2.General instruction
2.1 Copy the standard model dat a t o let EEPROM of the chassis have those d ata bef ore placing it on the
unit, do “factory adjustment” if necessary. If use a blank EEPROM directly, you should preset IIC data
and then do other common adjustment. Refer to TABLE1 to preset EEPROM.
2.2 the adjustment should be done under following circumstances without additional instruction
a) Alternating current 120V/60Hz
b) Preheat at least 30 min
2.3The unit has auto degaussi ng circuit , the auto de gaussing proce ss can be finishe d within 1s w hen the
main power. only when turn on the unit at least 30min after last time turn off TV does the auto
degaussing circuit work.
2.4 If the CRT with magnetism affects color purity and convergence, when t he aut o degaussing
eraser . if the color purity and convergence are st ill not very good, then corresponding adjustment
should be done. Refer to picture tube adjustment method for adjustment.
Alignment instruction
3
1
3.1 Debugging item
N
a)adjust mode instruction
b)B+ voltage adjustment
c)RFAG C voltage adjustment
d)focus adjustment
e)Screen-grid voltage white balance, sub brightness adjust ment
f)filed scan center , line , amplitude adjustment
g)H-scan center adjustment
3.2 Alignment flow
+B adjustment
ormal
temperature aging
Focus adjustment
AGC adjustment
White balance
adjustment
Picture adjustment
Fig-1 alignment flow
3.3 Enter/exit factory adjustment method
Use remote control, press “MENU” button, then press 6483,”M”will appear on screen to show that you
have entered the factory adjustment method, press “STANDBY” to exit it.
3.4 Select adjustment item and adjust data
After entering factory adjustme nt mode, press 1-4 n umber button s to select menu1- menu4; To enter into
MENU0~MENU5, press “CHILD LOCK” button and then the number button (5~0) to enter into relative
menus. Press “P+” and “P-” to select and “V+” and “V-”to adjust.
4 Alignment method
4.1 B+ voltage adjustment
a) connect B+ point with a digital voltmeter to measure the negative pole of VD524
b) receive PHILIPS test pattern signal and set the picture to standard.
c) Adjust VR501 to let the value of B+ voltage be 135 V ±0.5 V (yongxin super pure flat)
4.2 AGC adjustment
a) receive VHF-H band,60 dB RF signal.
b) Select factory menu2 of “AGC”.
c) Press “V+”,”V-”to let voltage value of tuner pin AGC be 3.8 V ± 0.1 V(DC).(if the selected tuner
is changed, then the voltage of AGC should be measured again: receive VHF-H band and 60
dB RF signal, adjust AGC-TOP to let the picture just without noisy, then the voltage of tuner
AGC is the required value for adjustment.)
d) exit factory menu
4.3 Normal temperature aging
a) do not receive signals.
2
b) under ”M” condition, set the accelerator to an appropriate point for aging.
4.4 Accelerator adjustment
a) do not receive signals;
b) select “SC” of factory menu3 to let the field scanning stop working.
c) adjust acceleration potentiometer to let bright lines just appears on screen.
d) exit SC menu.
4.5 High voltage check
Note: the main power voltage (B+=135 V)can affect the high voltage directly, so be sure to let the B+
power voltage accurate. Under any state, the high voltage should not exceed 30 kV.
a) connect an accurate high voltage meter between the second anode cap of picture tube and
ground.
b) turn on TV and receive testing card signal.
c) set picture to standard, the high voltage should be 27 kV± 1 kV.
d) the high voltage should not exceed 30KV with minimum brightness and contrast.
4.6 Focus adjustment
a) receive PHILIPS signal
b) adjust focus electrode potentiometer on FBT to optimize B area focus of screen.
4.7 White balance adjustment (color temperature 12000°K± 8MPCD,X=0.270± 0.008,Y=0.283± 0.008)
a) receive full white signal
b) select factory menu3
c) on the basis of blue, adjustment RD,GD of M3, let to white balance coincide with standard.
4.8 Filed scanning adjustment (fig-2)
a) receive PAL of PHILIPS test pattern signal.
b) select factory menu1
c) adjust V- SLO PE menu to let the horizontal center line of test pattern above blanking.
d) select V- SHI FT menu and adjust to let the vertical center of picture coincide with
vertical center of picture tube.
e) Select V-SIZE menu and adjust to let the vert ical reproduct ion ratio of picture acceptable.
f) Adjust V.SC to optimise the vertical S correction of picture.
g) Receive NTSC PHILIPS test pattern and readjust the above items.
4.9 Horizontal scanning adjustment (Fig-3)
a) Receive PAL PHILIPS signal
b) Select factory menu1
c) Select H.SHIFT menu and adjust to let the scanning horizontal center coincide with mechanical
center of picture tube
d) Exit M3 menu
e) Adjust VR433 to let horizontal reproduction ration of picture acceptable
f) Adjust VR432 to minimize left-right edge pincushion distortion of picture
Horizontal line
Under part banking
Fig-2 field scan adjustment
3
g) Adjust VR431 to minimize trapezoidal distortion
h) Exit factory menu
a
4.10 Sub-brightness adjustment
a) Receive PAL-D/K PHILIPS signal
b) Select “SB” of factory menu3
c) Adjust “SB” to let things between the sixth and seventh grey scale clear
4.11 OSD adjustment
a) Receive PAL-D/K PHILIPS signal
b) Select OSD H and OSD V of factory menu4. Adjust OSD H and OSD V to let OSD at a specified
place.
c) Exit factory menu
4.12 Degaussing
a) The unit has and auto degauss ing circuit, the degaussing circuit works several seconds after turning
on TV
b) If you want to move TV or change the direction, turn off TV and ten minutes later the degaussing
circuit will work
c) For better degaussing effect, you can use magnetic eraser
d) Move the magnetic eraser clockwise before your TV, when it is 2m away from your TV, turn off the
magnetic eraser. If the effect is still not very good, you can adjust “color pur it y” and “convergence”
4.13 Color purity correction
a) Turn on your TV
b) At least 15 minutes later, use anti-magnetized coil for degaussing
c) Obtain maximum brightness and contrast
d) Select factory menu3 and adjust to let R and B be zero, then let only green raster appear on the
screen at the moment
e) Loosen screws of deflection yoke frame to let vertical green belt appear on screen only
f) Move the rubber wedge
g) Rotate along neck of picture tube and slide color-purity magnets until the green belt at the middle of
screen and is vertical at the same time
h) Slowly move the deflectio n y oke backw ard of forwar d until the w h ole gre en rast er appears on scree n,
tighten the screws of the deflection yoke
i) Check the color purity of red raster and blue raster
j) Adjust white balance again to obtain white raster
4.14 Convergence correction
4.14.1 Central convergence correction
a) Turn on your TV
Fig-3 line scan adjustment
4
b) At least 15 minutes later, receive square test pattern signal
c) Adjust brightness and contrast to get the best picture
d) Adjust the angle of two tetrode magnetic rings to let the red vertical line coincide with the blue
vertical line at middle of screen
e) Keep the angle unchanged, move the two tetrode magnetic rings at the same time to let t he red and
blue horizontal lines coincide at middle of screen
f) Adjust two hexode magnetic rings to let the green line coincide with the mixed line of red and blue.
Adjust the angle between them will affect the vertical line, move them together will affect the
horizontal line.
g) Repeat d), e), f) and observe the movement of red, green and blue.
4.14.2 Ambient convergence correction
a) Turn on your TV
b) At least 15 minutes later, loosen the screws of the deflection yoke
c) Fixate the rubber wedge temporarily under the deflection yoke
d) Move the deflection yoke upward or downward to get best convergence, push the rubber wedge into
space between picture tube and deflection yoke to fixate the deflection yoke temporarily
e) Place the rubber wedge whose overlay paper has been removed at t he bot tom space
f) Move the deflection yoke left and right to get best convergence
g) Keep the condition unchanged, place another rubber wedge whose overlay paper has been
removed also at the upper space at the same time
h) Remove the interim rubber wedge, adhere it to picture tube and deflection yoke
i) After placing three rubber wedges, check all the convergence again
j) Stick three transparent viscous belts to the rubber w edge
2
Chart 1 I
2
C standard UOC for export bus control adjustment i tem default setting
AGCSPEED 1(AGC of speed)
FFI 0(IF PLL SPEED)
FMWS 1(frequency range of sound OFF=225KHZ,ON=450KHZ)
RP0 0(pre-shock and over-shock scale)
NTSCMATRIX USA
VOLPIN 0(1:push-pull output; 0: OC gate output.)
SOFT CLIP 3(white level limit)
PEAK WHITE 15(peak white limit)
CORING 0(coring noise reduction)
M7 AV2 1
SVHS 1
YUV 1
CONTRAST
0
75
6
VOLADJPOING 1(volume value have:1,25,50,75)
VOLVALUE 20(volume curve value:20,60,75,90)
M8 CATHOOELEVEL 7(cathode level)
UOCVOLUME 0(0:PWM terminal control; 1:UOC sound amplitude control of
inside)
FMATT 45(UOC sound output of amplitude) BTSC : 38
COMBFILTRE 0(N comb filter)
HEADPHONE 0(earphone function selection)
VM OPTION 0(VM function selection)
FRANCE 1 French
SPANISH 1 Spaish
POTUGUES 1 Portuguese
M9 NOM8377-B-6NA
STARTON 2(turn on)
STARTTIME 8(turn on time)
IF OFFSET 32(IF compensate)
TUNER OPTION 0(BXATB01 1F---X/ BXATB108F---K) 1 (BXATB017F---K) 2(XXX)
7
Block diagram
rCb
L
DY
S
F
S
TUNER
POWER
UNIT
SAW
135V
24V
16V
8V
5V
3.3V
S
TRAP
24C08
video
bus
TDA8377
IF IN Y IN
RF AGC V IN
U IN
CVBSINT
CHROMA
IFVO OUT
CVBS/Y IN
SDA
SCL
AUDIO OUT IK
RGB OUT
V OUT H OUT
V IN
TDA8177
V OUT
H IN
H OUT
H OUT
video
200V
+15V
-15V
Y
C
CRT PCB
CREEN
OCU
audio
video
CRT
video
4052
audio
N801
video
audio
Y
C
BU4052
V1i
ARo
ALo
ARi2
ARi1
A
ALi1
AN7522
Vi1
OUT1-
OUT1+
Vi2
OUT2-
OUT2+
Vo
V2i
S-VHS
i2
8
MAIN IC 8377:
ICs functional description
UOC TDA8377
SYMBOL PIN DESCRIPTION
STAND BY output. 1 In STAND BY mode, high level (Power OFF).
For Power ON this pin will be reduced to low.
SCL 2 I2C-bus clock line
SDA 3 I2C-bus data line
TUNING 4 tuning V o ltage (Vt) PWM output
P3.0/NTSC SW 5 Port 3.0 or NTSC output/SCART SW input, Forced NTSC selection,
Low-level output, otherwise High output.
KEY 6 Control keys input *3
9
VOL 7 Sound Volume control PWM output
MUTE 8 Sound mute output
VSSC/P 9 Digit ground for µ-controller core and periphery
BAND1 10 Tuner Band selection output
BAND2 11 Tuner Band selection output
VSSA 12 Analog ground of teletext decoder and digital ground of TV-processor
SECPLL 13 SECAM PLL decoupling
VP2 14 2nd supply voltage TV-processor(+8V)
DECDIG 15 decoupling digital supply of TV-processor
PH2LF 16 Phase-2 filter
PH1LF 17 Phase-1 filter
GND3 18 Ground 3 for TV-processor
DECBG 19 Band gap decoupling
AVL/EWD 20 Automatic volume leveling /EAST - WEST drive output
VDRB 21 Vertical drive B output
VDRA 22 Vertical drive A output
IFIN1 23 IF input 1
IFIN2 24 IF input 2
IREF 25 Reference current input
VSC 26 Vertical sawtooth capacitor
TUNER AGC 27 Tuner AGC output
AUDEEM/SIFIN1 *1 28 Audio deemphasis or SIF input
DECSDEM/SIFIN2 29 decoupling sound demodulator or SIF input 2
GND2 30 ground 2 for TV processor
SNDPLL/SIFAGC *1 31 narrow band PLL filter or AGC sound IF
AVL/SNDIF/REF0/
AMOUT *1
HOUT 33 horizontal output
FBISO 34 flyback input/sandcastle output
AUDEXT/QSSO/
AMOUT *1
EHTO 36 EHT/overvoltage protection input
PLL IF 37 IF-PLL loop filter
IFVO/SVO 38 IF video output / selected CVBS output
VP1 39 supply voltage TV processor
CVBS INT 40 internal CVBS input
GND1 41 ground for TV processor
CVBS/Y 42 CVBS/Y input
CHROMA 43 C input
AUDOUT/AMOUT
*1
INSSW2 45 2nd RGB / YUV insertion input
32 Automatic V olume L evellin g / sound I F input / subc arrier ref erence outp ut
R2/VIN 46 2nd R input / V (R-Y) input / PR input
G2/YIN 47 2nd G input / Y input
B2/UIN 48 2nd B input / U (B-Y) input / PB input
BCLIN 49 beam current limiter input
BLKIN 50 black current input / V-guard input
RO 51 Red output
GO 52 Green output
BO 53 Blue output
VDDA 54 analog supply of Closed Caption decoder and digital supply of
TV-processor (3.3 V)
VPE 55 OTP Programming Voltage
VDDC 56 digital supply to core ( 3.3 V)
OSCGND 57 oscillator ground supply
XTALIN 58 cryst a l oscillat or input
XTALOUT 59 crystal oscillator out put
RESET 60 reset
VDDP 61 digital supply to periphery (+3.3 V)
P1.0/INT1 62 TV/AV (AV1) / AV2 /S-VHS mode Output.
P1.1/T0 63 TV/AV (AV1) / AV2 /S-VHS mode Output.
P1.2/INT0 64 Remote control signal input.
Symbol PIN Function Symbol PINFunction
INV IN 1 Input V OUT 5 Vertical output
VCC1 2 Power VCC2 6 Out put pow er supply
PUMP UP 3 Pump up power NON INV IN 7 Negative feedback
GND 4 Ground
WARNING: BEFORE SERVICING THIS CHASSIS, READ THE "X-RAY RADIATION PRECAUTION
"SAFETY PRECAUTION" AND "COMPONENTS SAFETY NOTICE" ON PAGE 1 OF THIS MANUAL.
CAUTION: 1. The shaded areas makes in the schematic diagram and the parts list designate
componentswhich have special characteristics important for safety and should be replaced
only with type identical tothose in the original circuit or specified in the parts list. Before
replacing any of these components,read carefully the COMPONENTS SAFETY NOTICE
on page 1.
2. Do not degrade the safety of the receiver through improper servicing.