Text preview for : 066ets.pdf part of LG 066ets LG TV LP-XG1 066ets.pdf
Back to : 066ets.pdf | Home
TROUBLESHOOTING
1. Power
Connect AC voltage to power case
CHECK. A and disconnect all connectors of
signal processor and ballast.
- Check AV voltage.
- Check output voltage 6871VPN004A Check Fuse
(250V-380V DC) No
Yes
Fuse interruption
Check S/W waveform of No
Check B
6871VPN007A(100KHz)
Yes
Connect PON of 6871VPN005A and
ST5V with 1K ohm resistance.
No Check the voltage marked on Yes Short of signal
Check C
6871VPN005A connector processor is expected.
- 1 -
CHECK. B
Symptoms Cause / Check Disposal
A. IC200 is not oscillated. 1. Check the interruption of R200. 1. Replace it.
2. Blows up : --- 2. Check interruption and replace it.
3. Rectifier diode failure of the second 3. Check oscillation waveform after replacing IC200
side. and removing D204A and D204B.
If oscillation is normal, replace diode.
4. Check D201 interruption 4. Replace D201.
B. IC200 is oscillated 1. Check short of circuit of the 2nd side.
intermittently and 2. Check failure of D204C.
makes noise in trans.
C. Voltage of the 2nd side 1. IC201 failure. 1. Replace IC201.
swings irregularly.
CHECK. C
Symptoms Cause / Check Disposal
A. 5V is blocked. 1. 5V regulator failure. 1. Separate D301 and check 5V voltage.
Check IC305, 301 and 300.
B. 12V is blocked. 1. 12V regulator failure. 1. Check 12V as above.
Check IC304.
C. 15.5V is blocked. 1. Check the collector of Q300 becomes 1. Check and replace D300 or Q300.
0V by R300.
2. IC306 failure. 2. Replace IC306.
D. Fan 12V is blocked. 1. IC303 failure. 1. Connect Fon terminal of P102A with
ST5V and 1Kohm resistance. Output
becomes 0V when pin 4 is low. Check
12V after removing resistance and
- 2 -
2. Digital
2-1. If video signal is not output and screen shows only blue background
(1) Input H, V sync line is poor ( when displaying no signal )
--> BA7657 Input tantal capacitor
--> No M52347 input
(2) TDA4885 input power is not normal
--> 12V power input L1206 is in poor connection
--> No clamp input
2-2. If a color is dark or different with other color signal
--> Q1130, Q1131, Q1132(KTK211Y )
--> BA7657 Input tantal capacitor
--> IC1502, IC1503, IC1504 are not operated.
2-3. When screen is intermittently displayed and signal is not output repeatedly
--> Operation of Q1388(V-MUTE3) is poor
--> Operation of IC1505, IC1506, IC1507 is poor
2-4. When a color has problem in some gray on output screen, or has stripes in one color
--> Connection of IC1042, IC1043, IC1044 is poor
2-5. If set operation is not normal
--> Input power is not normal and L1002 is poorly connected.
--> Connection of R1562, R1570, R1572 is poor
--> Operation of IC11033(KIA7042F) is poor
- 3 -
3. LCD Driver
1. Only color stripe is displayed on output screen and image is 5. Output image is reversed horizontally.
not displayed.
PC1
PC1
- Reason : HCK 1/2 pulse of CXD2453Q is changed each other.
- Reason : H sync of CXA3106Q is not operated. - Reason : RGT and XRGT of CXA2111R are changed each
other.
2. Only OSD is output on black screen and letters are displayed
horizontally and vertically in many lines. 6. Double folded images are displayed by space of 12 pixels.
PC1 PC1 PC1
PC1 PC1
- Reason : Output clock of CXA3106Q is not operated. - Reason : Adjustment of POS 1/2 of CXA2112R goes wrong.
3. Image is not displayed and only milky screen is output. 7. Vertical bar noise is displayed on the full screen by space of
12 pixels.
- Reason : PCG pulse of CXD2453Q is not output.
- Reason : S/H video output of CXA2112 or more output is not
4. Color is not regular and color band is shown on the right end operated.
of screen.
8. Output image is darker and more faint than normal image.
- Reason : SID output waveform of CXA2112R is not normal.
- Reason : V33 voltage(3.3V) of CXA2111R is not supplied to
CXA2112R normally.
- 4 -