Changhong LCD TV Repairing Tips

                             
                               

21K39PH – 21K51PH – PF2114PH – PF2115PH

DEAD SET

R528, FUSE, R502, L502, L503, V512, VD515,

BRIDGE RECTIFIER DIODES

CHANGING CHANNEL NOT FINE TUNED
DEFECTIVE DIODE NEAR JUNGLE IC

NO MENUR733 10K Ohms OPEN

ADJUST SCREEN RETRACE GREEN HAVE SCREEN

GOOD B+ STANDBY ONLY NO HIGH VOLTAGE OUT
PUT VIDEO IN AND OUT = GOOD = GOOD SYSTEM IC AND JUNGLE GOOD
AUTO PROGRAM THE UNIT CHANNEL CHANGING BUT NO SOUND
= DEF JUNGLE IC

BURNT RX02
RXO1 NOT MATCH THE ORIGINAL

OVERHEAT H-OUT
LEAKAGE H-OUT OR CAPACITOR

STANDBYEEPROM, SENSOR
PINCUSIONING CAPACITOR BLOWN
RM11C SHORTED

WHITE SREEN
JUNGLE IC,( LA76814K )

NO PICTURE
TUNER, DEMODULATION IC, IF TRANSFORMER, JUNGLE IC, SYSTEM IC

VIDEO PRESS MANY TIMES PICTURES GONE
BC SUPPLY UP TO 7.5 VOLTS , REPLACE 8.2V DIODE AS BLOCKING DIODE TO PRODUCED 0.28V BASE OF R G B

ABNORMAL VERTICAL ONE LINEHANG PIN#7 OF SYSTEM IC IF VERTICAL RETRACE APPEARS ON SCREEN ,

V702 = A1015 DEFECTIVE

BURN THE REGULATORC3807 AND VD515 OPEN

NO MENUR722, R723, V704, V703

OSCILATE NO RASTER BLACK SCREEN
CHECK: VIDEO OUT- GOOD
- VIDEO IN – GOOD
- V704 & V703 COLLECTOR = 5VOLTS
- RESISTOR BIAS 10K Ohms
- R725 & R733 OPEN
- DEF V704

NO HEATER
RF481, FLYBACK TRANSFORMER,

HORIZONTAL LINE OUTPUT TRANFORMER,

HORIZONTAL LINE OUTPUT TRANSISTOR,

HORIZONTAL DRIVE TRANSISTOR, AND

JUNGLE IC ( LA76814K )

NO VIDEO INCPU OR SYSTEM IC DEFECTIVE

RETRACE LINEV901, V902, V903, AND

COLOR DRIVE TRANSISTORS

ABNORMAL VOLTAGERF551, VD586, V582, V583

NO SIGNAL
TUNER ( TDQ-6F2M )

IF TRANSFORMER, SAW TOOTH FILTER,

CHECK 5 VOLTS AND 45 VOLTS
NOTE: 45 VOLTS MUST BE 21-22.5 VOLTS VCC,

5 VOLTS MUST BE 4.8 VOLTS IF

45 VOLTS MEASURES 31 VOLTS

IT MEANS NO 5 VOLTS SUPPLY OR LOOSE CONTACTS,
MEMORY MAY POSSIBLE
JUNGLE DEFECTS IF NO RASTER

PF2914PH NOT OSCILATESCHECK:

POWER SUPPLY TO ACTUAL
- NO 5V-2
- 8V = 1V ONLY
- NO STANDBY VOLTAGE
- SUSPECTED AREAS:
- BCJA18D OSCILATOR DEFECTIVE
- CPU
- JUNGLE IC
- MEMORY

21F SERIES

CAUSE AND DEFECTS

OSCILATE NO PICTURE
CHECK- 3.3 VOLTS ( V512 ) = A1569 TRANSISTOR,
- PIN # 33 OF IC BUS OMS 837X ,

PIN# 54, 56, AND 61 IS 3.3 VOLTS
- HANG PIN# 10 OF JUNGLE IC

IF TV SET POWER UP DEFECTIVE JUNGLE IC
- V805 =A1015
- HANG UP C839
- PIN#33 JUNGLE IC 0.48V TO H-DRIVE BASE
- 1200MGhz REPLACE IF HIGH VOLTAGE TOO HIGH

OUTPUT OR NO OUTPUT
- C824A DEF

NO PICTURE BLACK SCREEN
OSCILATE NOT POWER ON

– CHECK
- +B 115 VOLTS.
- COLLECTOR OF HORIZONTAL OUTPUT 115V UP TO 118.5V
- BASE OF H-OUT 0.22VOLTS IF NOT FIND OTHER CAUSE
- V810, V811, D831
- COLLECTOR OF V810 = 1.98V IF NOT D831 LEAKAGE
- PIN# 45 OF IC BUS OPEN IF VOLTAGE EXCIST TO 4.5V
- HANG UP THE C839 THEN TRY TO RUN THE TV SETS IF IT WORKS PROPERLY REPLACED THE D831 OR OTHER RELATED X-RAY PROTECTION CICUITS

oscilate only not power on

CHECK +B 115 TO 118.5 VOLTS, STANDBY VOLTAGE 90 TO 93 VOLTS
- 3.3 VOLTS OF PIN# 45, 54, 56, & 61 IF GOOD CHECK
- 3.3V BECOME 1.6V IF ATTACHED TO JUNGLE IC JUNGLE IC

REPLACE THE A1569 3.3V REGULATOR
- MEMORY VOLTAGE 5V, 4.56V, & 4.58V IF GOOD
- REPLACE EEPROM 24C16
- AUDIO DEMODULATOR IC( N106 ) = TDA9859
- DEMODULATION IC ALSO RESPONSIBLE FOR THE OSCILATION

OR SWITCHING LOW VOLTAGE SECTION
- REPLACE THE TDA9859 IF DEFECTIVE

HANG PIN#15, 16, 17 &18
- CHECK ALSO 5V REGULATOR 7805

NO LEFT AUDIO
CHANGE EEPROM

NO VIDEO INPUT SIGNAL AND SOUND WITH AIREAL OR CABLE SIGNALV213 DEFECTIVE = C1815
R309 OPEN 1K OHMS

NO AIREAL SIGNAL WITH VIDEO INPUT SIGNAL
V214 DEFECTIVE = A1015,

N808=LM317T 8.2 VOLTS REGULATOR,

C824A= 35V/1000uf , C861= 16V/1000uf
RAINBOW COLOR APPEARS ON SCREEN
REPLACE VERTICAL IC

BURN RY22SHORTED TO GROUND THE CRT SOCKET AND

NEED TO REPLACED A NEW ONE

IF NO GREEN COLOR OR VOLTAGE UP TO 185V VY06 NEED TO REPLACE

STANDBY NO OTHER ACTION OF THE TV SETHANG UP C839, IF IT WORKS D831 DEFECTIVE AND

OTHER RELATED X-RAY PROTECTION CIRCUITS.
- TRY TO CHANGE EEPROM,
- AUDIO DEMODULATOR
- A1569=3.3V REGULATOR
- REGULATOR = STR G8653 OR 8656

OSCILATE NO PICTURE NO HEATER
NO VOLTAGE IN D831 CHANGE IC BUS AND MEMORY
- 190V = 150 ONLY AND ABNORMAL
- 30V GOOD IF FLYBACK HANG UP BUT DECREASE IF CONNECTED
- H-DRIVE AND PRE-DRIVE GOOD
- R841 CHANGE VALUE = 15K BECOME 25K Ohms
- R260 OPEN

OSCILATE AUTO PICTURE
LOOSE CONTACT IN JUNGLE IC BUS NEED RESOLDER OR CHANGE IC

OSCILATE NO PICTURE BLACK SCREEN WITH HEATER
CHECK: R G B SUPPLY FROM JUNGLE IC BUS 2.0 OR 1.98V TO 2.53V

IF IT EXCEEDED OR 3.0

CHECK 8.2 VOLTAGE SUPPLY FROM LM317T AND

THE FILTER CAPACITOR
L805 MUST 8.2 VOLTS IF ITS ALL GOOD

REPLACE THE JUNGLE IC MAY DEFECTIVE
R867 DEFECTIVE AND D838

AUTO SHUT ON AND OFF H-OUT NOT RUN
H-DRIVE TRANSISTOR C2688 LEAK
VERTICAL RETRACE UPPER LINE
R402 CHANGE VALUE

AUTO SHUT ON BLUE BACK AND NO OTHER ACTIONS
JUNGLE IC DEFECTS

OSCILATE NOT POWER UP STILL STANDBY MODE
JUNGLE IC DEFECTIVE

POWER BLINKS ONLY BACK TO STANDBY MODE680 Ohms = R804 OPEN,

STR G8653 LEAKGE,

EEPROM
D822 SHORTTED= RG2,

NO PICTURE BLACK SCREEN BUT HAVE MENU
LM317T SECTION 8.2 VOLTS DEFECTIVE

OUT OF HORIZONTAL SYNCR255 SHORTED TO GROUND
C388 DEFECTIVE
JUNGLE IC

29F PIN CUSTIONING DEFECTS
EW SECTION CANT ADJUST,

68K Ohms =R409 OPEN

29F18 RETRACE LINE UPPER SIDE
R403 CHANGE VALUE

29F18 BURN SUPPLY TO HEATER & G2 BRIDGE CAPACITOR
CHANGE FLYBACK

FLECKERING WHEN AUTO PROGRAMR841 CHANGE VALUE,

C206 LEAKAGE

VERTICAL NOT ENOUGHR403 CHANGE VALUE 0.33Ohms TO 0.15 Ohms

LIGHTNING EFFECTS
C206A OPEN OR SHORTED AND

R841 CHANGE VALUE

LOW VOLTAGE B+V802 COLLECTOR TO EMITTER OPEN

LOW VOLTAGE BLINKING DEFECTSB+ ABNORMAL = R804 680 Ohms CHANGE VALUE AND

C810 LEAK

PF29F15PH AND PF29F18PH WIDE VERTICAL OR STRETCHED
MEASURE THE VD501 OR VD402 & VD437

IF GOOD WHILE HANG UP BUT

SHORTED WHEN ATTACHED= VERTICAL IC DEFECTIVE

SMALL RETRACE APPEARS ON SCREEN R G BREPLACE JUNGLE IC

NO SIGNAL
TUNER,

SAW TOOTH FILTER, JUNGLE IC,

NO PICTURE WITH SOUNDS
H-DRIVE OPEN

INTERMITTENT DEADSET
H TRANSFORMER LOOSE CONNECTION

NO RIGHT AUDIODEFECTIVE AUDIO PROCESSOR TDA9859

PRESS ANY BUTTONS EVEN REMOTE MENU APPEARS ON SCREEN
JUNGLE IC DEFECTIVE

NO COLORMEMORY AND 1200MGhz DEFECTIVE

H1418PH IN COMPLETE CHANNELSTUNER OR JUNGLE IC

ONE CLICK ONLY AND LIGHT INDECATOR BLINKS ONLYCHANGE MEMORY

NO SIGNAL RECIEVEDCHECK: VIDEO IN = GOOD- TUNER
- SHORTING THE SAW FILTER WILL

DETECTS OR ISULATE THE CAUSE ETHEIR

JUNGLE OR TUNER SECTION IF RASTER APPEARS JUNGLE OK
- MEMORY= GOOD
- TUNER = GOOD
- FR AMP = GOOD
- DEMODULATION = GOOD
- 3.3V= GOOD
- 5V = GOOD
- 3.39V = GOOD
- 22V = GOOD
- 8.2 VOLTS MAY LEAK

H1418PH WHITE VERTICAL LINES STRIPSCHECK: VIDEO OUT = GOOD
- RGB VOLTAGE = 6V INSTEAD OF 3.0 VOLTS
- RGB AMP = 55V- 190V = GOOD
- VD301= A1015 DEFECTIVE

STANDARD CRT TUBE SHUT OFF AFTER 30 MINUTES TO 2HrsLY01 NOT CONNECTED AN

GROUND TO HEATER GROUND OPEN

AUTO PROGRAM = GOOD BUT NO CHANNEL APPEARS AFTER FINISH
SERVICE MODE NOT FUNTION TOO
REPLACE THE MEMORY

B+ GOOD BUT NO FLYBACK B+R501 OPEN AND H-OUT

14F98PH BURN R406R406 = 10 Ohms
REPLACE D402

STANDBY ONLYC823 DEF

AUTO POWER ON NO PICTURE
MEMORY DEFECTIVE

BLURD PICTURE
G2= 50 VOLTS ONLY
CY04 = OPEN

BURN R821
MEMORY REVERSED CONNECTION

OVERHEAT H-OUT
LEAK H-OUT
C502 &C501 = DEFECTIVES

NO SECONDARY VOLTAGECHECK: PHOTO COUPLER
- REGULATOR
- B+ DIODE RG2
- R803 CHANGE VALUE= 0.27 Ohms
- D805 = RU2 OR AK03
- C808= 2KV/680P