Service manual

ManualsBrandsSharp ManualsFlat Panel TVLC-20B4U

LC-20B4U-S

LC-20B4U-B

TROUBLE SHOOTING TABLE

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?

MODEL A620

INCH SIZE 20

ERROR NO RESET 0

PUBLIC MODE OFF

V-CHIP 1

CANADIAN VCHIP OFF

EXT CONTROL OFF

VPC SHARPNESS ON

VER ROM 1.00A GAIBU 0.000

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) Tuner 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, Q3601

(3) Lamp error detection circuit (Tuner PWB and Main PWB)D3601, D3602,

D3603, D3604, D3605, D3606, D3607, D3608, D3609, Q3602, Q3603, Q3604,

Q3605, Q3606 and their peripheral parts as well as pin (42) of IC2001

No or Wrong

Picture

Does the IC806

test pattern appear

properly?

Does the IC1201 test

pattern appear

properly?

Check the IC806 signal

output line, IC806 itself

and its peripheral

circuits.

Are the waveforms at

pins (8), (9), 26), and

(27) of IC1201 as

specified?

Check IC1201 and its

peripheral circuits as

well as the LCD panel

voltage and waveform.

Check the related lines,

IC806 itself and its

peripheral circuits.

Are the waveforms at the signal

input pins of IC806 as specified?

TV/Composite … Pin (73)

S Video … Pins (72) and (73)

Component … Pins (1), (2), (3)

and (75)

Check the IC806 signal

input line.

Check IC806 and its

peripheral circuits.

Yes