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CHASSIS  LD21B
SERVICE MANUAL
READ THE SAFETY PRECAUTIONS IN THIS MANUAL
 SPECIFICATION
CONTENTS
SAFETY PRECAUTIONS
SERVICING PRECAUTIONS
 IMPORTANT SAFETY NOTICE
SAFETY PRECAUTIONS
 Electrostatically Sensitive ES Devices
SERVICING PRECAUTIONS
 Removal
IC Remove/Replacement
Replacement
Small-Signal Discrete Transistor Removal/Replacement
 3. Test method
SPECIFICATION
4. Model General Specification
1. Application range
 DVB-S QPSK  2 ~ 45Msymbol/s
Symbolrate  4.0Msymbols/s to 7.2Msymbols/s
symbolrate
DVB-S2 8PSK / QPSK  2 ~ 45Msymbol/s
 5.2. RGB Input PC
5. Video resolutions 2D
5.1. Component Input Y, CB/PB, CR/PR
 PCDVI
5.3. HDMI InputPC/DTV
 2. Designation
ADJUSTMENT INSTRUCTION
Boot file Download
1. Application Range
 7. ADC Calibration
3.1. ADC Process
3.3. EDID data
3.2. EDID Download
 3.4 Function Check
4. Total Assembly line process
4.1. Adjustment Preparation
 6. Model name & Serial number D/L
4.3. Outgoing condition Configuration
6.1. Signal Table
5. HI-POT Test
 GP4LOW
7. MAC Address & CI+ key download
6.3. Method & notice
7.1 MAC Address
 7.3. LAN PORT INSPECTIONPING TEST
7.2 LAN Inspection
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SCREW ASSEMBLY WORKING GUIDE
Screw specification and application situation
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 LG2111 A
BLOCK DIAGRAM
Rear
Side
 EXPLODED VIEW
 for SYSTEM EEPROM
GP4LS7LR22011.12.01
Copyright  2012 LG Electronics. Inc. All rights reserved
to delete CI or gate for
 DDR3
Normal Power
VDDC
Normal
 +1.5VDDR
FROM LIPS & POWER B/D
PowerDET
+3.3VNormal
 IR/LED and control for normal models
 USB2DIODES
USB SIDE
USB1DIODES
 HDMI
 FILRE AND ELECTRICAL SHOCK HAZARDS, WHEN SERVICING IF IS
RGB-PC / SPDIF
THE  SYMBOL MARK OF THIS SCHEMETIC DIAGRAM INCORPORATES
SPECIAL FEATURES IMPORTANT FOR PROTECTION FROM X-RADIATION
 For Comsumer model, use 4PIN Wafer
RS-232C
COMMERCIAL/NonOS MODEL OPTION COMMERCIAL MODEL OPTION
 LVDS for large inch
 H5TQ1G63DFR-H9C
S7LR2DIVXMS10
GP4LS7LR22011/06/03 DDR25612
IC1201
 SFLASHMAINWINBOND IC1401-*1 W25Q80BVSSIG
Serial Flash for SPI boot
SFLASHMAINMACRONIX
 HEAD
Headphone *Option  HEADPHONE
PHONE
 10067972-0500LF
CI Region
Option name of this page CISLOT because of Hong Kong
 ETHERNET
H/W option  ETHERNET
GP4LS7LR22011/06/14 ETHERNET21
 TDSQ-G001D
GP4RGLOBALTUNERBLOCK
TU2602TU2603 TDSS-G101D TDSN-G301D
TU2601
 DCDCGND and AGND are connected
DVB-S2 LNB Part Allegro
OptionLNB
GP4LS7LR22011/11/02 DVBS27
 PSC008-01
SCART / COMPONENT&COMPSIT
FULL SCART / COMPONENT1
JK2801
 AUDIO AMPSTA380BWE
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 Contents of LCD TV Standard Repair Process
 Content
Contents of LCD TV Standard Repair Process Detail Technical Manual
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Error symptom
 A2 Check Power Board 24v output
A. Video error
LCD TV
Main B/D↔ Power B/D, LVDS Cable,Speaker Cable,IR B/D Cable
 or 24V…
voltages of Power
Check various
Board  3.5V,12V,20V
 Signal Quality Normal over 50%
By using Digital signal level meter By using Diagnostics menu on OSD
Menu→ Set up→ Support → Signal Test Signal strength Normal  over 50%
 → Set-Top-Box, Different maker TV etc
 Link Cable
A8/ A9
Check color by input -External Input COMPONENT -RGB
※ Check
 Check color condition by input -External Input -Component RGB
External device screen error-Color error
Vertical/Horizontal bar, residual image, light spot
Connect other external device and cable
 Measure voltage of each output of Power B/D
B. Power error
Check Power LED
Check Power On ‘”High”
 POWEROFFCPUABNORMAL
Check Power Off Mode
If Power Off mode is not displayed Check Power B/D voltage
POWEROFFABNORMAL1
 Check audio B+
C. Audio error
24V of Power
Check user menu  Speaker off
 Check audio B+ Voltage
In case of External Input signal error Check and fix external device
 Check & Repair
D. Function error
1. Remote controlR/C operating error
 Replace Main B/D
Check input signal
Y Check technical Signal information input? - Fix information
Recognition error
 Identify nose type
E. Noise
 F. Exterior defect