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Soft Touch Key Pad Resistance and Diode Mode Checks

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Soft Touch Key Pad Resistance and Diode Mode Checks IC100 on the Front IR Board is generating these Resistance changes when a Soft Touch Key is touched. This in turn pulls down the Key 1 and Key 2 lines to be interpreted by the Microprocessor. P100 (Key 1, Key 2) Resistance Reading with Soft Touch Key pressed. KEY Pin 3 measured from Gnd KEY Pin 4 measured from Gnd CH (Up) 0.61K Ohms Volume (+) 3.6K Ohms CH (Dn) 9K Ohms Volume (-) 0.62K Ohms Input 3.66K Ohms Enter 22K Ohms Menu 9K Ohms P100 Voltage Measurements with Soft Touch Key pressed. KEY Pin 3 measured from Gnd KEY Pin 4 measured from Gnd CH (Up) 2.1V Volume (+) 0.89V CH (Dn) 1.619V Volume (-) 0.214V Input 0.88V Enter 2.42V Menu 1.667V P100 Connector "IR/LED Control Board" to P703 "Main" (No Key Pressed) Diode Mode Readings taken with Pin Label STBY Run Diode Mode all connectors Disconnected. Black 3 KEY 1 3.3V 3.29V 2.58V lead on Gnd. DVM 4 in Diode Mode. KEY 2 3.3V 3.29V 1.58V 127 July 2010 50PJ350 Plasma

Section	Page
50PJ350 PLASMA TRAINING PACKAGE	1
OUTLINE	2
Overview of Topics to be Discussed	3
LG Contacts	4
Preliminary Matters (The Fine Print)	5
ESD Notice	6
Safety and Handling, Checking Points	7
Basic Troubleshooting Steps	8
50PJ350 PRODUCT INFORMATION SECTION	9
50PJ350 Specifications	10
50PJ350 Logo Familiarization Page 1 of 3	11
50PJ350 Logo Familiarization Page 2 of 3	12
50PJ350 Logo Familiarization Page 3 of 3	13
600Hz Sub Field Driving	14
50PJ350 Remote Control	15
50PJ350 Rear and Side Input Jacks	16
50PJ350 Dimensions	17
DISASSEMBLY SECTION	18
Removing the Back Cover	19
Circuit Board Layout	20
Connector Identification	21
Disassembly Procedure for Circuit Board Removal	22
Disassembly Procedure for Circuit Board Removal (2)	23
X Drive Circuit Board Removal Continued	24
Getting to the X Circuit Boards	25
Left and Right X Drive Connector Removal	26
TCP (Tape Carrier Package) Generic Removal Precautions	27
Left and Right X Drive Removal	28
CIRCUIT OPERATION, TROUBLESHOOTING AND CIRCUIT ALIGNMENT SECTION	29
Signal and Voltage Distribution Block Diagram	30
Panel Label Explanation	31
Adjustment Notice	32
SWITCH MODE POWER SUPPLY SECTION	33
Switch Mode Power Supply Overview	34
Power Supply Board Layout (Drawing)	35
Power Supply Circuit Layout	36
Power Supply Basic Operation	37
Power Supply Turn On Sequence	38
Power Supply Va and Vs Adjustments	39
Power Supply Static Test with Light Bulb Load	40
Power Supply Static Test (Forcing on the SMPS in stages)	41
SMPS Connector P813 Identification, Voltages and Diode Check	42
SMPS Connector SC101 and P812 Identification, Voltages and Diode Check	43
Y-SUS BOARD SECTION	44
Y-SUS Block Diagram	45
Y-SUS Board Layout	46
Y-SUS Board Component Layout Drawing	47
VSC and -VY Adjustments	48
Y-Drive Signal Overview	49
Locking on to the Y-Drive Waveform Tip	50
Observing (Capturing) the Y-Drive Signal for Set Up Adjustment	51
Set Up and Set Down Adjustments	52
Set Up Adjustment Too High or Low	53
Set Down Adjustment Too High or Low	54
Y-SUS Board Troubleshooting VScan	55
Y-SUS Board P212 Connector to P205 Lower Y-Drive (Logic and FG5V)	56
Y-SUS Board P212 to Lower Y-Drive P205 Logic Signals Explained	57
Y-SUS P212 Connector Diode Mode Testing	58
Y-SUS Floating Ground (FG 15V) and (FG 5V) Checks	59
Y-SUS 16V Generation Checks	60
P101 Y-SUS to Control Board Fuse Information	61
Y-SUS P113 and P114 Plug Information	62
Y-SUS P211 Plug Information	63
Y-SUS P101 to Control P111 Plug Voltage Checks	64
Y-DRIVE BOARD SECTION	65
Y-Drive Board Layout	66
Y-Drive Upper Layout	67
Y-Drive Lower Layout	68
Y-Drive Diode Check Scan and FG	69
Y-Drive Buffer Troubleshooting	70
Y-Drive Upper P110 Connector Voltage and Diode Check	71
Y-Drive Lower P204 Connector Voltage and Diode Check	72
Removing (Panel) Flexible Ribbon Cables from Y-Drive Upper or Lower	73
Incorrectly Seated Y-Drive Flexible Ribbon Cables	74
Z-SUS SECTION	75
Z-SUS Block Diagram	76
Z-SUS Board Component Identification	77
Z-SUS Board Drawing	78
Z-SUS Waveform	79
VZB (Z-Bias) VR201 Adjustment	80
Connector P2 to Y-SUS P211 Voltages and Diode Checks	81
Connector P1 to Control P102 Voltages and Diode Checks	82
CONTROL BOARD SECTION	83
Control Board Pictorial	84
Control Board Component Identification and Checks	85
Control Board Temperature Sensor Location (Chocolate)	86
Locking on to the Y-Drive or Z-Drive Waveform Tip	87
Checking the Crystal X101 “Clock” on the Control Board	88
Control Board Signal (Simplified Block Diagram)	89
Control Board Connector P111 to Y-SUS P101 Voltages and Diode Mode Checks	90
Control P111 to Y-SUS P101 Plug Information	91
Control Board LVDS P121 Signals	92
Control Board LVDS P121 Connector Voltages and Diode Check	93
Control Board P101 Connector Pin ID and Voltages	94
P161 Connector \	95
P162 Connector \	96
X BOARD (LEFT, RIGHT and CENTER) SECTION	97
X Board Additional Information	98
X Board TCP Heat Sink Warning	99
X Board Layout Primary Circuit Diode Check	100
TCP (Tape Carrier Package)	101
TCP Testing	102
TCP 3.3V B+ Check	103
TCP Visual Observation. Damaged TCP	104
Left X Drive P122 Connector from Y-SUS P203 Information	105
P121, P212, P211 and P331 X Board Connector (VA Diode Check)	106
MAIN BOARD SECTION	107
Main Board Layout and Identification	108
Main Board Drawing (Front Side) Component Layout	109
Main Board Drawing (Front Side) Component Voltages	110
Main Board (Back Side) Component Layout	111
Main Board (Back Side) Component Voltages	112
Main Board Tuner Explained	113
Main Board Crystal X1, X402 and X401 Check	114
Main Board P703 (Removing the LVDS or SMPS Cable)	115
Main Board P703 LVDS Video Signal Test Points	116
Main Board Plug P703 “LVDS” Voltages	117
Main Board Plug P704 to Ft IR Board	118
Main Board Plug P301 to Power Supply Voltages and Diode Check	119
Main Board Speaker Plug P801 Voltage and Diode Check	120
FRONT IR, POWER LED and SOFT TOUCH KEY PAD SECTION	121
Front Control (IR and Intelligent Sensor) Board and Power LED Board Location	122
Front Control Board Connector P100 Voltage and Pin Identification	123
Front IR Board Plug P101 to Soft Touch Keys (Voltages and Pin Identification)	124
SOFT TOUCH KEY PAD SECTION (Board Layout and Identification)	125
Soft Touch Key Pad	126
Soft Touch Key Pad Resistance and Diode Mode Checks	127
INVISIBLE SPEAKER SYSTEM SECTION	128
INTERCONNECT DIAGRAM (11 X 17 Foldout) SECTION	129
Circuit Interconnect Diagram	130
LVDS Video Signal Waveforms	132