Sharp Aquos LC 20B1U, Service Manual

Page: 24 / 70

LC-20B1U
24
TROUBLE SHOOTING TABLE
No
No P
o
wer (P
o
wer LED indicator still in red)
Go to the adjustment process mode
.
Mo
v
e
the cursor to ERR
OR NO RESET
and clic
k on it (to reset to z
ero).
T
u
rn
off the po
w
e
r.
Is the po
w
er tur
ned on again?
1
INCH SIZE
20
MODEL
B1U
CARD
ON
SYSTEM
N358
NTSC PWM FREQ
OCO
P
AL PWM FREQ
OBD
NTSC PWM DUTY
0
P
AL PWM DUTY
0
TV GAIN
OFF
ERR
OR NO RESET
5
V
-CHIP
1
CANADIAN VCHIP
OFF
B1U VER
1.xx
Note:
This model is equipped with the lamp error detection function that detects the current flo
wing into the fluorescent lamp and protects the bac
klight lamp dr
iv
e circuit.
If a lamp error is detected, the microprocessor interr
upts the unit and the ERR
OR NO
RESET setting will go up
.
When the ERR
OR NO RESET setting has reached "5", the microprocessor tur
ns and
k
eeps off the unit's po
w
e
r.
T
o
resume the po
w
e
r,
tak
e the abo
v
e
procedure to clear the
ERR
OR 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
Wr
ong
Picture
Does the IC801 test patter
n appear
proper
ly?
Does the IC1201 test patter
n appear
proper
ly?
Chec
k the IC801 signal
output line
, IC801 itself
and its per
ipher
al
circuits
.
Are the w
a
v
e
fo
rms at
pins (10), (11), (13), (15) and (17) of IC1201 as specified?
Chec
k IC1201 and its
per
ipher
al circuits as
w
ell as the LCD panel
v
oltage and w
a
v
e
fo
rm
.
Chec
k the related lines
,
IC801 itself and its per
ipher
al circuits
.
Are the w
a
v
e
fo
rms at the signal
input pins of IC801 as specified? TV/Composite
…
Pin (73)
S Video
…
Pins (71) and (72)
Component
…
Pins (4), (5), (6)
and (75)
Chec
k the IC801 signal
input line
.
Chec
k IC801 and its
per
ipher
al circuits
.
No
No
No
No
Yes
Yes
Yes
Yes