LG 37LB5RT-TB Schematic

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LCD TV
SERVICE MANUAL
CAUTION
BEFORE SERVICING THE CHASSIS, READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
CHASSIS : LP7BA
MODEL : 37LB5RT 37LB5RT-TB
website:http://biz.LGservice.com
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To Instrument's exposed  METALLIC PARTS
AC Volt-meter
Good Earth Ground such as WATER PIPE, CONDUIT etc.
1.5 Kohm/10W
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Copyright © 2007 LG Electronics. Inc. All right reserved. Only for training and service purposes
LGE Internal Use Only
6. EDID
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NO
Plug in a power cord
Connect a cable .
NO
Plasma (E L11), LC D(SC100 )
Replace the fuse
NO
Connect the 13pin cable.
NO
Symptom
1) Minute discharg e doesn’t occur at module.
Start check
2) Front LE D does n’t come into action.
Is inser ted a pl ug
1. No power
in power cord?
YE S
Is connected the Line
YE S
Filter and PSU?
Is norma l the fuse of
PSU? Plasma (F 101),
YE S
LCD(F111 )
Is it connected that
PSU and 13 p in cable
YE S
in VSC board ?
After remo ve all cab les con nec ted to
PSU (except the C N101) , author izes the AC
vo ltage marking on manual.
When ST -b y 5V doesn’t operate , replace PSU
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Replace Y-B/D
Replace Z -B/D
Is output the no rm ality Low /H igh
NO
Replace the power board
Voltage except Stand-by 5V ?
Replace the power board
After connecting we ll each
connector the nor mality it operates?
NO
YE S
YE S
Is normal the output voltage after
remove P1 connector of Y-B/D?
NO
Is normal the fuse
(FS2,FS3 ) on Y-B/D?
NO
Is normal the output vo ltage after
Replace the fuse
NO
YE S
Is normal the fuse
NO
YE S
remove P1 connector of Z-B/D?
(FS1,FS2 ) on Z-B/D?
Replace the fuse
YE S
YE S
After remove P100,110 output voltage normality:
Is norm al the output vo ltage
Re pla ce Right X-B/ D
NO
Afte r re mo ve P200,210 output voltage norm ality:
after remove P100,110,200, 210
Replace Left X- B/D
connector of X- B/D?
no rmal?
Is the PSU
Symptom
1) After once shining, it doesn’t discharge minutely from module.
2) The relay falls. ( Th e sound is audible "Click ")
Start check
3) It is converted w ith the color where the front LED is red from green .
2. Protection mode
Is the each
connector norma l?
Is t he Y- Board
no rm al ?
no rm al ?
Is the Z - Board
no rm al ?
Is t he X- Board
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Replace
Is output the normality Lo w/High
NO
Is the
the power boa rd
Voltage except Stand-by 5V?
YE S
on?
inverter/ VaV s
NO
Does minute
discharge at
Sy mptom
1) No OSD and image occur at scr een.
Start check
2) It maintains the condition where the front L ED is gre en
3. No Raster
Module?
Reconnect the link cable
Check the PDP/LCD Module
YE S
in P600
NO
YE S
norm al?
Is the link cable
NO
Is the IC700’s
Replace the VSC
output norm al?
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(Check Pin5, Pin4)
Is normal the I2C communication ?
(Check Pin8, Pin6)
Is normal the Input voltage ?
Change the TunerCheck the powerCable inserts well.
Is normal the
I2C communication ?
(Check R309, R310)
YE S
Change the IC(IC300)
4. In case of becomes unusual display from RF mode(Main)
NO NO NO
connected well?
Is the Tuner Cable
NO YE S YE S
YE S
of the Tuner?
Is normal video output
(Check TU200_Pin14)
NO NO
(Check L308)
Is normal the Input voltage ?
NO
of CXA2069Q?
Is normal video
A
check R324, R328)
output
(Check R324, In case of S-Video
Check the power
YE S
( Check L1004)
Cable inserts well
NO
YE S
connected well?
Is the LVDS Cable
Change the IC(IC700)
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Check the input source
Check the input source
Check the input source
NO
YES
of the A/V jack?
Is normal video input
5. In the case of becomes unusual display from rear AV mode(main)
Same as Block A
6. In the case of becomes unusual display from rear S-Video mode(main)
NO
YES
of the A/V jack?
Is normal video input
Same as Block A
NO
YES
of the A/V jack?
Is normal video input
Same as Block A
7. In the case of becomes unusual display from side AV mode(main)
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Check the input source
Check the input source
Check the input source
NO
YES
of the A/V jack?
Is normal video input
(Check R339, R341, L310)
8. In the case of becomes unusual display from side S-Video mode(main)
Same as Block A
9. In the case of becomes unusual display from SCART 1 mode(main)
NO
YES
(Check R102)
of the A/V jack?
Is normal video input
Same as Block A
NO
YES
of the A/V jack?
Is normal video input
(Check L111, L112, L106)
Same as Block A
10. In the case of becomes unusual display from SCART 1_RGB mode(main)
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Check the input source
Check the input source
NO
YES
(Check R115)
of the A/V jack?
Is normal video input
11. In the case of becomes unusual display from SCART 2 mode(main)
Same as Block A
12. In the case of becomes unusual display from SCART 2_YC mode(main)
NO
YES
of the A/V jack?
(Check R115, R149)
Is normal video input
Same as Block A
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(Check Pin5, Pin4)
Is normal the I2C communication ?
Change the Tuner
NO NONO
( L1103)
(Check Pin8, Pin6)
Is normal the Input voltage ?
Check the power
YES YES
connected well?
Is the Tuner Cable
Cable inserts well.
NO
Is normal the
(Check R309, R310)
I2C communication ?
Change the IC(IC300)
NO NO
(Check L308)
Is normal the Input voltage ?
Check the power
( Check L1004)
YES YES
Cable inserts well
NO
YES
of the Tuner?
Is normal video output
(Check TU201_Pin14)
Is normal video
B
13. In case of becomes unusual display from RF mode(Sub)
of CXA2069Q?
check R312, R314)
output
(Check R312, In case of S-Video
YES
connected well?
Is the LVDS Cable
YES
Change the IC(IC700)
Same as the case of main except block A should be change to B
14. In case PIP doesn’t display from other modes(Sub)
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Check the input source
Check the input source
Check the input source
NO
YES
of the JK102?
Is normal video
input
(Check L126, L127, L128)
15. In case of becomes unusual display from component1 mode(main/sub)
Change IC(IC700)
16. In case of becomes unusual display from component 2 mode(main/sub)
NO
YES
of the JK103?
Is normal video
input
(Check L129, L130, L131)
Change IC(IC700)
NO
YES
R513, R515)
Is normal R, G, B input
(Check R509, R511, R512
and H,V sync of the JK500?
Change IC(IC700)
17. In case of becomes unusual display from RGB mode(main/sub)
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in menu
Set on speaker
Check the
Speaker cable
Replace IC400
Replace IC401
Replace IC402
YES
on in menu?
Is the speaker
NO NO
NO
YES
Is the speaker
cable normal?
NO
normally?
IC400 operate
Replace IC300
NO
YES
normally?
IC401 operate
NO
YES
normally?
IC402 operate
NO
YES
Replace VSC B/D
Download the EDID data
YES
LED is Green
Screen is exi stent, but sound isn’t
Symptom
Check f ollow
is no sound?
All input (mode)
Only HDMI is
18. No Sound
no Sound?
NO
YES
YES
normal?
Is the output
of IC300(pin52,53)
NO
no Sound?
Only AV input is
after IC300
Check the signal
refer to circuit diagram
YES
Check the Tuner In/Out
NO
Only RF is
no Sound?
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Down load EDID data each port.
1. Check TV input mode.
(HDMI1 port support HDM I and DVI.
So if you inpu t D VI signa l and PC audio from phone jac k,
You can hear PC audio . )
Replace IC1200
No
Normal video ,
is appropria tely enabled .
2. Unplug and plug HDMI ca ble.
(sometimes ESD surge occurred at HDMI port.)
3. Check HDMI Mute re gister. (0x 68, offset 0x37)
4. Check Audio - out channel mute reg is ter (0x68 , offse t 0 x32)
Check HDMI source . Change anothe r source or cab le.
No
Normal aud io?
Yes
Is normal on ly video ?
No
Yes
Is norm al on ly audio?
No
Check TMDS line wave.
(R1215 ~ R1222/ R1226 ~ R1233)
19. HDMI mode
Yes
Is wave continuous?
1. Check H DMI rece iver’s status registe r. (0x60, offset 0x06)
o
rmal.
- If t he value is 0xf or 0x8, it is n
2. Check HD CP reg iste r. (0 x60, offset 0x32 )
-Enabl e bit 6: HDCP key loaded
-Enable bit 5: HDCP de cry ptio n active
Reset TMDS powe r down /on reg ister .
-0x60, offse t 0x3f : 0xf 7 => 0xff
-Enable bit 4: HDCP authen. attempted
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Change Timeshift M ode
from off to "On"
Connect a cable.
P1300, P1302
Replace the IC1300, IC1302
Replace the IC1500, IC1501
Change HDD
NO
Menu? in
Start check
Is Timeshift Mode "On"
LED is Green
Doesn’t work time shift mode.
Can’t enter to r ecorde d list
Can’t re cord AV/RF/Component
Sympto m
Check f ollow
20.1 DVR
NO
YE S
(P1300, P1302 )
Is connected cable?
NO
Is operated
normally?
IC 1300,IC1302
YE S
NO
1
operated
YE S
normally?
Is
IC1500, IC150
YE S
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400
820
520
610
811
804
600
530
300
200
800
700
803
805
806
807
802
120
810
800
500
809
808
510
910
900
801
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Copyright © 2007 LG Electronics. Inc. All right reserved. Only for training and service purposes
LGE Internal Use Only
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Copyright © 2007 LG Electronics. Inc. All right reserved. Only for training and service purposes
LGE Internal Use Only
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Copyright © 2007 LG Electronics. Inc. All right reserved. Only for training and service purposes
LGE Internal Use Only
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Copyright © 2007 LG Electronics. Inc. All right reserved. Only for training and service purposes
LGE Internal Use Only
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Jul., 2007
Printed in KoreaP/NO : MFL39265905
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