Sharp LC-20C2E (serv.man9) Service Manual ▷ View online
13
LC-20C2E
[9] Lamp error detection
9-1. Function
For added safety, this LCD color TV set is equipped with the lamp error detection function. In case of lamp or
lamp circuit failure, the power is automatically turned off.
If by any chance the lamp or the lamp circuit gets in trouble or if a lamp error detection is activated for some
reasons, the TV set behaves as follows.
lamp circuit failure, the power is automatically turned off.
If by any chance the lamp or the lamp circuit gets in trouble or if a lamp error detection is activated for some
reasons, the TV set behaves as follows.
1
The TV set power can be turned on, but off in about 5 seconds. (The power LED indicator on the front panel
turned from green to red.)
turned from green to red.)
2
If the above action
1
happens 5 times in row, the TV power cannot be turned on any longer. (The power
LED indicator stays in red.)
9-2. Measures
9-2-1. Turning off the lamp error detection function
9-2-1. Turning off the lamp error detection function
If the power is turned off because of the above lamp error, the power LED indicator turns red and the set goes
to the adjustment process mode. Now the error detection function turns off and the power turns on instead.
In this way, the lamp and the lamp circuit can be checked for their performance.
Also make sure the “ERROR NO RESET” setting in the 7th line on page 1 of the adjustment process is above
1. When over 1, it means the lamp error detection has been activated.
to the adjustment process mode. Now the error detection function turns off and the power turns on instead.
In this way, the lamp and the lamp circuit can be checked for their performance.
Also make sure the “ERROR NO RESET” setting in the 7th line on page 1 of the adjustment process is above
1. When over 1, it means the lamp error detection has been activated.
9-2-2. Resetting the lamp error counter
First make sure the lamp and the lamp circuit function well, and then reset the lamp error counter to zero.
Select the “ERROR NO RESET” item in the 5th line on page 1 of the adjustment process and reset the setting
to “0” using the VOL+/- buttons.
Select the “ERROR NO RESET” item in the 5th line on page 1 of the adjustment process and reset the setting
to “0” using the VOL+/- buttons.
Finally check the performance to make sure the lamp error detector is not activated.
Page 1 of the adjustment process
1
+ B
A D J
1
6
0
M O D E L
C 2 E
I N C H I
S
I Z E
1
5
N T S C
P W M
F R Q
0 C 0
E R R O R
N O
R E S E T
5
P M U T E
O F F
1
1
1
1 C 2 E 1 V E R
1
.
0
0
0
Reset to zero.
[8] Factory settings
Make the factory settings using the adjustment remote controller. Either of the following remote control codes
works.
works.
Key name
R/C Code
Factory setting
100000111111110
Factory setting
100000001010110
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
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