DOWNLOAD Sharp LL-T2020 (serv.man12) Service Manual ↓ Size: 1.7 MB | Pages: 34 in PDF or view online for FREE

Model
LL-T2020 (serv.man12)
Pages
34
Size
1.7 MB
Type
PDF
Document
Service Manual
Brand
Device
Monitor / Complete
File
ll-t2020-sm12.pdf
Date
PREV: Sharp LL-T2020 (serv.man11) Service Manual

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LL-T2020
TROUBLESHOOTING
4 – 3
(No)
(No)
(No)
(Yes)
(Yes)
(No)
(Yes)
(No)
(Yes)
(No)
(Yes)
(No)
(Yes)
(No)
(Yes)
(Yes)
(Yes)
(No)
(No)
(No)
(Yes)
(Yes)
(Yes)
(Yes)
(No)
(Yes)
(No)
(No)
(No)
(Yes)
(No)
(No)
(Yes)
(No)
(Yes)
(Yes)
Check DC+5V power supply line (PV5) , 
POWER_CTL3 signal, and circuits around 
Q807.
Check DC+2.5V power supply line (DV25), 
POWER_CTL4 signal, and circuits around 
IC802.
Check DC+12V power supply line (LCDV), 
POWER_CTL2 signal, and circuits around 
Q803.
Check clock circuit around IC501 and X501.
Clock (R508) and DE (R502) signal outputs 
are normal?
ADJUSTMENT and MODE SELECT are set 
properly?
Signal waveform of test terminal LD502 is 
normal?
ADJUSTMENT and MODE SELECT are set 
properly?
Adjust according to "screen adjustment 
procedure".
Adjust according to "screen adjustment 
procedure".
Check circuits around IC301, IC302, and 
IC402.
Check circuits around IC701, and CN701 
and LCD module.
Check DC+5V power supply line (DV5A), 
POWER_CTL1 signal, and circuits around 
Q807.
Test terminals LD405, LD523, and LD701 are 
DC+3.3V?
Signal waveform of test terminal LD565 is 
normal?
Test terminals LD401, LD402, and LD403 are 
DC+3.3V?
Test terminal LD815 is DC+5V?
Test terminal LD806 is DC+5V?
Test terminal LD801 is DC+12V?
Test terminal LD501 is DC+2.5V?
LD816 is DC+12.0V?
36th pin of LC602 is in H level (DC+5V)?
The entire LCD screen is white?
The entire LCD is black?
The size of LCD screen is abnormal?
 LCD screen jitters or flickers?
Check circuits around IC401.
Check circuits around IC403.
Check circuits around IC601.
Test terminal of LD701 is DC+12V?
Check circuits around X601 and IC602.
Check circuits around IC502.
Check circuits around CN701.
Check PLL circuits around IC402.
Check circuits around IC502.
4
Check inverter unit, inverter cable and their
connections.
(No)
(Yes)
When CN802 cable is removed, LD801 is 
DC+12V?
Check the power unit and cable and their 
connections, and DC+12V power supply 
line.
LL-T2020
TROUBLESHOOTING
4 – 4
(No)
(No)
(No)
(Yes)
(Yes)
(Yes)
(Yes)
(No)
(No)
(Yes)
(No)
(No)
(Yes)
(Yes)
(Yes)
(No)
(Yes)
(No)
(No)
(Yes)
(No)
(Yes)
(No)
(Yes)
(No)
(Yes)
(Yes)
(No)
(Yes)
(Yes)
(No)
(No)
(Yes)
(Yes)
GAIN CONTROL and WHITE BALANCE 
are set properly?
Analog color signal output (C302, C303, 
C305, C319, C320, and C322) is normal?
Digital color signal output of IC402 (ID0    
ID47) is normal?
Digital color signal output of IC502 (OD0    
OD47) is normal?
Check circuits around IC701, and CN701 
and LCD module.
Check circuits around IC402, IC404, and 
IC602.
Digital color signal output of IC402 (ID0    
ID47) is normal?
Press INPUT key to switch over to the 
correct input signal port.
Check CN101 and 201, and signal source 
and digital signal cable.
Check circuits around IC101, IC103 and 
IC201.
Check CN101 and 201, and signal source 
and digital signal cable.
Display is normal in composite sync and sync-
on-green signal input.
Adjustment settings are stored after display 
screen is adjusted?
AUTO function of GAIN CONTROL operates 
properly?
Input signal port is the one to which digital 
signal cable is connected?
Waveforms of IC103s and 201s 1st and 2nd 
pins change normally when resolution is 
changed?
Test terminals LD110, LD111, LD112, LD113, 
LD210, LD211, LD212, LD213 are DC+3.3V?
CN101 and 201 signals (at 1st, 2nd, 9th, 10th, 
17th, 18th, 23rd, and 24th pins) are normal?
IC102 and IC202 signal output (ID0    ID47, 
HIS, IVS, ICK, IACT) are normal?
LCD screen color is abnormal?
Input is changed over properly?
No error.
Display is normal in analog input?
LD101 and LD201 are in H level (DC+5V)?
Check circuits around IC502.
Adjust according to "screen adjustment 
procedure".
Check circuits around IC402.
Check circuits around IC402 and IC502.
Check circuits around IC502 and IC701.
Check circuits around IC402 and IC404.
Check circuits around IC602.
check circuits around IC602 and IC605.
Check circuits around IC402.
First, check with analog signal input.
Check circuits around IC104 and IC203.
Check circuits around IC102 and IC202.
continued from  4
The display does not work. (with digital connection, DVI-D cable use)
LL-T2020
WAVE FORM
5 – 1
CHAPTER 5. WAVE FORM
Waveform measurement condition: Input each of the display patterns
and measure the waveform (tinming chart).
CAUTION
WAVE FORM 1: REFCK (LD565)
Frequency: 81MHz
Display screen: Arbitrary
2V/DIV, 10ns/DIV
WAVE FORM 2:  XTAL (IC601 of 2PIN)
Frequency: 24MHz
Display screen: Arbitrary
1V/DIV, 25ns/DIV
WAVE FORM 3: VSYNC (LD305, LD318)
Frequency: 60Hz
Display screen: Arbitrary
1V/DIV, 5ms/DIV
WAVE FORM 4:  HSYNC (LD304, LD317)
Frequency: 75kHz
Display screen: Arbitrary
1V/DIV, 5
µµµµ
s/DIV
Wave-form
No.
Measurement 
point
Name of 
waveform
Display pattern
1
LD565
REFCK
Arbitrary
2
IC601 of 2PIN
XTAL
Arbitrary
3
LD305, LD318
VSYNC
Arbitrary
4
LD304, LD317
HSYNC
Arbitrary
5
LD502
ICK
Arbitrary
6
LD504
VS
Arbitrary
7
LF505
IHS
Arbitrary
8
IC701 of 10PIN DCLK
Arbitrary
9
IC701 of 9PIN
DEN
Arbitrary
10
LD300, LD301, 
LD302
RGB OUT
16 monochromatic 
gradation patterns
Oscilloscope: Tektronix644B
Input signal:
VESA1600 x 1200
H: 75kHz  V: 60Hz
DOTCLK: 162MHz
GND
GND
GND
GND
LL-T2020
WAVE FORM
5 – 2
WAVE FORM 5: ICK (LD502)
Frequency: 81MHz
Display screen: Arbitrary
1V/DIV, 5ns/DIV
WAVE FORM 6:  VS (LD504)
Frequency: 60Hz
Display screen: Arbitrary
1V/DIV, 5ms/DIV
WAVE FORM 7:  IHS (LD505)
Frequency: 75kHz
Display screen: Arbitrary
1V/DIV, 5
µµµµ
s/DIV
WAVE FORM 8:  DCLK (IC701 of 10PIN)
Frequency: 81MHz
Display screen: Arbitrary
1V/DIV, 5ns/DIV
WAVE FORM 9:  DEN (IC701 of 9PIN) 
Frequency: 75kHz
Display screen: Arbitrary
1V/DIV, 5
µµµµ
s/DIV
WAVE FORM 10: RGB OUT ( LD300, LD301, LD302)
Display screen: 16 monochromatic gradation patterns
0.5V/DIV, 5
µµµµ
s/DIV
GND
GND
GND
GND
GND
GND
Page of 34
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