Sharp LC-20B2UA, Service Manual

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22
LC-20B2UA
TROUBLE SHOOTING TABLE
No
No Power (Power LED indicator still in red)
Go to the adjustment process mode.
Move the cursor to ERROR NO RESET and click on it (to reset to zero).
T
urn of
f the power
.
Is the power turned on again?
1
INCH SIZE
20
MODEL
B2UA
SYSTEM
N358
NTSC PWM FREQ
OCO
P
A
L
PWM FREQ
OBD
NTSC PWM DUTY
0
P
A
L
PWM DUTY
0
TV GAIN
OFF
ERROR NO RESET
5
V
-CHIP
1
CANADIAN VCHIP
OFF
B2UA
VER 1.xx
Note:
This model is equipped with the lamp error detection function that detects the current flowing into the fluorescent lamp and protects the backlight lamp drive circuit. If a lamp error is detected, the microprocessor interrupts the unit and the ERROR NO RESET
setting will go up.
When the ERROR NO RESET
setting has reached "5", the microprocessor turns and
keeps of
f the unit's power
.
T
o
resume the power
, take the above procedure to clear the
ERROR NO RESET
setting.
Check the following points. (1) Backlight lamp (2) Inverter circuit (inverter PWB and main PWB)F6700, F6701, F6702, F6703,
F6704, D6700, D6701, Q6700, Q6701, Q6702, Q6703, Q6704, Q6705, Q6706, Q6707, Q6708, Q6709, Q6710, Q6711, Q6712, Q6713, Q6714 and their peripheral parts as well as pin (34) of IC1201
(3) Lamp error detection circuit (terminal PWB and main PWB)D3600, D3601,
D3602, D3603, D3604, D3605, D3606, D3607, Q3600, Q3601, Q3602, Q3603, Q3604 and their peripheral parts as well as pin (42) of IC2001
No or W
rong
Picture
Does the IC801 test pattern appear properly?
Does the IC1201 test pattern appear properly?
Check the IC801 signal output line, IC801 itself and its peripheral circuits.
Are the waveforms at pins (10), (1
1), (13),
(15) and (17) of IC1201 as specified?
Check IC1201 and its peripheral circuits as well as the LCD panel voltage and waveform.
Check the related lines, IC801 itself and its peripheral circuits.
Are the waveforms at the signal input pins of IC801 as specified? TV/Composite … Pin (73) S V
ideo … Pins (71) and (72)
Component … Pins (4), (5), (6) and (75)
Check the IC801 signal input line.
Check IC801 and its peripheral circuits.
No
No
No
No
Yes
Yes
Yes
Yes