Service manual
27
LC-20C3U-S
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).
Turn off the power.
Is the power turned on again?
1
MODEL A460
INCH SIZE 20
SYSTEM N358
NTSC PWM FREQ OCO
PAL PWM FREQ OBD
NTSC PWM DUTY 0
PAL PWM DUTY 0
TV GAIN OFF
ERROR NO RESET 5
PUBLIC MODE OFF
V-CHIP 1
CANADIAN VCHIP OFF
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 off the unit's power. To 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, D3608, Q3600, Q3601, Q3602,
Q3603, Q3604 and their peripheral parts as well as pin (42) of IC2001
No or Wrong
Picture
Check IC801 and its
peripheral circuits.
No
No
No
No
Yes
Yes
Yes
Yes
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), (11), (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 Video … Pins (71) and (72)
Component … Pins (4), (5), (6)
and (75)
Check the IC801 signal
input line.