LC-20C2E (serv.man4). Part 2 - Troubleshooting, Block diagrams - p14-28 — Sharp TV Service Manual (repair manual)

Model
LC-20C2E (serv.man4)
Pages
13
Size
91.69 KB
Type
PDF
Document
Service Manual
Brand
Device
TV / LCD / Part 2 - Troubleshooting, Block diagrams - p14-28
File
lc-20c2e-sm4.pdf
Date

View Sharp LC-20C2E (serv.man4) Service Manual online

14
LC-20C2E
TROUBLE SHOOTING TABLE
No picture, No sound
Check all the settings microprocessor's adjust process menu.
Do F2, F3, F4 and F5 
function?
Are T701's secondary 
outputs, +38V, +16V, +9V, 
+5V and -8V normal?
Remove F2, F3, F4 and F5 
and check the load side.
Is there short-circuiting?
Is there short-circuiting of 
T701 primary side periphery, 
Q751, Q753 and P901.
Replace F2, F3, F4 and F5.
Check P901 and 
connection cable.
Is T701's primary oscillator 
waveform normal?
Check T701's secondary 
load.
Yes
Yes
No
No
No
No
Yes
Fluorecent lamp failure to light up
Does F1 function?
Is the pin 34 of IC1201 in 
the "H" state?
Is the Q3603 short-circuiting?
Is there short-circuiting of 
T5701 and T5702 primary 
side periphery, Q751~Q753.
Yes
Yes
No
No
No
Yes
Replace the fluorecent lamp 
with new one and check 
again.
Yes
Check the OFL1 line, IC1201 
and their peripheral parts.
Check Q3603 and their 
peripheral parts.
Check T5701, T5702, 
Q5701~Q5703 and 
connection cable.
15
LC-20C2E
TROUBLE SHOOTING TABLE
 (Continued)
No picture
Check all the settings microprocessor's adjust process menu.
Is in/output of 
IC801 normal?
Is in/output of
IC1201 normal?
Check IC801
and its 
peripheral parts.
Check IC1201 
and its 
peripheral parts.
Check IC402 
and its 
peripheral parts.
Check IC801, 
AV1 line and its 
peripheral parts.
Check LCD 
panel voltages 
and waveform.
Yes
Yes
No
No
No picture 
at all
Is in/output of 
IC402 normal?
Is input at pin 
73 of IC801 
normal?
Yes
No
No
No TV and 
VIDEO 1 
output
Is voltages at 
pin 3 of W7 and 
pins 3, 4, 5 of 
W14 tuner
normal?
Is output at pin 
2 of W7 tuner 
normal?
Check the 
power line.
Check tuner 
and its 
peripheral parts.
Is input at pin 
3 of IC402 
normal?
Is the pins 2 
and 4 of IC402 
at "H" and "L" 
state?
Yes
Yes
No
No
No
No
No
Yes
No TV output
Is the pins 65 
and 66 of 
IC2001 at "H" 
and "L" state?
Yes
Check the its 
line.
Check the its 
line.
Check IC402 
and its 
peripheral parts.
Is input at pin 
1 of IC402 
normal?
Is the pins 2 
and 4 of IC402 
at "L" state?
Check the its 
line.
Check the its 
line.
Check IC402 
and its 
peripheral parts.
Is the pins 65 
and 66 of IC2001 
at "L" state?
Yes
Yes
No
No
No
No VIDEO 1 
output
16
LC-20C2E
TROUBLE SHOOTING TABLE
 (Continued)
No picture
Check all the settings microprocessor's adjust process menu.
Is input at pin 
74 of IC801 
normal?
Check the AV2 
line and their 
peripheral parts.
Check the W9, 
SY-line, SC-line 
and their 
peripheral parts.
No
No VIDEO 2
output
Is input at pins 
71 and 72 of 
IC801 normal?
No
No S-VIDEO 
output
Is input at pin 
70 of IC801 
normal?
Check the 
V2VO line and 
their 
peripheral parts.
No
No line 
output
Is input at pins 
1, 2, 3, 56, 57 
and 79 of IC801 
normal?
Is output at pins 
11, 13 and 16 
of I4 normal?
Check IC801
and their 
peripheral parts.
Check I13 and 
their 
peripheral parts.
Check I9 and 
their 
peripheral parts.
Check I4 and 
their 
peripheral parts.
Is output at pins 
11, 13 and 16 
of I13 normal?
Yes
Yes
No
No
No
No TELETEX 
output
Is output at pins 
44~49 of I9 
normal?
Yes
No
17
LC-20C2E
TROUBLE SHOOTING TABLE
 (Continued)
No picture
Check all the settings microprocessor's adjust process menu.
Is source GND 
normal?
Is CSCOM 
waveform 
normal?
Check R1212 
and their 
peripheral parts.
Check IC1109, 
Q1101, Q1102, 
D1101, R1120, 
R1130 and their 
peripheral parts.
Check R1231 
and their 
peripheral parts.
Yes
No
No
Becomes
dark
No
Time passes,
becomes 
dark
Is gate GND 
normal?
Is gate clock
(GCK) normal?
Check R1223 
and gate aray 
peripheral parts.
Yes
No
Check D1201 
and their 
peripheral parts.
No
Is B-5.5V being 
outputted?
Is VCC being 
outputted?
Check T701's 
secondary +5V
outputs line?
Yes
No
Is GSP 
waveform 
normal?
Check R1223 
and their 
peripheral parts.
Yes
No
Becomes
white.
Is 3.3V VHS 
being 
outputted?
Is source clock 
normal?
Check +3.3V 
outputs line of 
IC752.
Check R1210, 
R1211 and their 
peripheral parts.
Check FB1203 
and gate aray 
peripheral parts.
Is output of LBR 
and HG 
normal?
Yes
Yes
No
No
No
Vertical line 
output
No picture
Check all the settings microprocessor's adjust process menu.
Is output of 
R0~R5 
normal?
Is output of 
G0~G5 
normal?
Is output of 
B0~B5 
normal?
Check R1202,  
R1203 and their 
peripheral parts.
Check R1204,  
R1205 and their 
peripheral parts.
Check R1206,  
R1207 and their 
peripheral parts.
Check T701's 
secondary +5V 
outputs line.
Yes
Yes
No
No
Colour is 
unusual
Is VLS 5V 
being 
outputted?
No
Picture 
image is 
gloomy
Is in/output of 
SPIO and 
SPOI normal?
Check R1209 
and their 
peripheral parts.
No
No picture
image 
inversion
Is output V0, 
V16, V32, V48 
and V63 
normal?
Check IC1106, 
IC1107, IC1108 
and their 
peripheral parts.
No
Gradation
defect
Is output of U/D
 normal?
Check Q1201 
and their 
peripheral parts.
Yes
No
Page of 13
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Here you can view online or download Sharp LC-20C2E (serv.man4) Service Manual in pdf. This Service Manual can help you recover, restore, fix, disassemble and repair Sharp LC-20C2E (serv.man4) LCD. Information contained in Sharp LC-20C2E (serv.man4) service manual (repair manual) typically includes:

  • Disassembly, troubleshooting, programming, maintenance, remote, adjustment, installation and setup instructions.
  • Schematics, wiring and block diagrams.
  • Printed wiring boards (PWB) and printed circuit boards (PCB).
  • Parts list (bill of materials).