Read LG 42PN4500-SA (CHASSIS:PB31A) Service Manual online
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6. GND and ESD Testing
6.1. Prepare GND and ESD Testing.
■ Check the connection between set and power cord
6.2. Operate GND and ESD auto-test.
■ Fully connected (Between set and power cord) set enter the
Auto-test sequence.
■ Connect D-Jack AV jack test equipment.
■ Turn on Auto-controller(GWS103-4)
■ Start Auto GND test.
■ If its result is NG, then notice with buzzer.
■ If its result is OK, then automatically it turns to ESD Test.
■ Operate ESD test
■ If its result is NG, then notice with buzzer.
■ If its result is OK, then process next steps. Notice it with
Good lamp and STOPER Down.
6.3. Check Items.
■ Test Voltage
● GND: 1.5KV/min at 100mA
● Signal: 3KV/min at 100mA
■ Test time: just 1 second.
■ Test point
● GND test: Test between Power cord GND and Signal
cable metal GND.
● ESD test: Test between Power cord GND and Live and
neutral.
■ Leakage current: Set to 0.5mA(rms)
6.4. POWER PCB Ass’y Voltage adjustment
(Va, Vs voltage adjustment)
6.4.1. Test equipment :
: D.M.M 1EA
6.4.2. Connection Diagram for Measuring
: refer to fig.1
<XPOWER4 42T4H PSU>
6.4.3. Adjustment method
6.4.3.1. Vs adjustment (refer fig.1)
(1) Connect + terminal of D.M.M. to Vs pin of P811, connect
-terminal to GND pin of P811
(2) After turning VR901, voltage of D.M.M adjustment as same
as Vs voltage which on label of panel left/top ( deviation ;
±0.5V)
6.4.3.2. Va adjustment (refer fig.1)
(1) After receiving 100% Full White Pattern, HEAT RUN.
(2) Connect + terminal of D.M.M. to Va pin of P811, connect
-terminal to GND pin of P811
(3) After turning VR502,voltage of D.M.M adjustment as same
as Va voltage which on label of panel left/top (deviation;
±0.5V)
7. Default Service option.
7.1. ADC-Set.
■ R-Gain adjustment Value (default 128)
■ G-Gain adjustment Value (default 128)
■ B-Gain adjustment Value (default 128)
■ R-Offset adjustment Value (default 128)
■ G-Offset adjustment Value (default 128)
■ B-Offset adjustment Value (default 128)
7.2. White balance. Value.
7.3. Temperature Threshold
■ Threshold Down Low
20
■ Threshold Up Low
23
■ Threshold Down High
70
■ Threshold Up High
75
8. USB DOWNLOAD(*.epk file download)
■ Put the USB Stick to the USB socket
■ Press Menu key, and move OPTION
■ Press “FAV” Press 7 times
(fig.1) PCB Assy Voltage adjustment
Center(Default)
COOL
Mid
Warm
R Gain
192
192
192
G Gain
192
192
192
B Gain
192
192
192
R Cut
64
64
64
G Cut
64
64
64
B Cut
64
64
64
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