Sharp LC-20S4US Operation Wartungshandbuch PDF herunterladen (Seite 30)

LC-20S4U-S

30

TROUBLE SHOOTING TABLE (Continued)

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

No

No

No

No

No

No

No

No

No

No

No

Yes

Yes

Yes

Is there the lack of sound in any input

mode (TV, video 1/2, component)?

No sound from right and left speakers

Check the following points:

1Monitor output set at "variable"?

2Sound volume at minimum?

3Mute effect on?

4Headphones connected?

Do the following and check again:

1Set the monitor output to "Fixed".

2Turn up the sound volume.

3Clear the mute effect.

4Disconnect the headphones.

Check the following points:

1Sound heard from speakers?

2Monitor output properly connected?

3Mute effect on?

Do the following and check again:

1Go to "No sound from speakers".

2Reconnect the monitor output properly.

3Clear the mute effect.

Is the voltage at pin (7) (power input terminal)

of IC3301 as specified (about +12.5V)?

Is the voltage at pin (5) (standby control terminal)

of IC3301 as specified (about +2V)?

Is the supply voltage of each circuit as follows?

Pin (39) of IC3201: About +8V

Pins (65) and (66) of IC3201: About +5V

Pins (11), (12) and (13) of IC3201: About +3.3V

Are the following control signals fed as follows?

Pin (2) of IC3201: SCL1

Pin (3) of IC3201: SDA1

Are the audio signal outputs at pins (27)

(Rch) and (28) (Lch) of IC3201?

Are the oscillation waveforms at pins (71)

and (72) of IC3201 as specified?

Check the lines from between pins (27)

(Rch) and (28) (Lch) of IC3201 to pins

(4) (Rch) and (2) (Lch) of IC3301.

Check IC3201 and its peripheral circuits.

Check X3201 and its peripheral circuits.

Check the lines from pins (29) and (30)

of IC2001 to pin (2) of IC3201.

Check the line between pin (56) of IC2001 and

pin (5) of IC3301.

Check the following points:

+8V Line: check IC3702 and its peripheral

circuits as well as the line up to Pin

(39) of IC3201.

+5V Line: check IC702, Q713 and their

peripheral circuits, B5V700MA line,

Q3702 and its peripheral circuits,

and +5V line of IC3201.

+3.3V Line: check IC703, Q712 and their

peripheral circuits, B3.3V1.2A line,

and +3.3V input line of IC3201.

Check the built-in AC power supply and the line up

to pin (7) of IC3301.

Check the following points:

1No TV sound: check Q3201, Q3202 and

TU3401, and their peripheral circuits.

2No Video 1 input sound: check the lines from

J3402 to pins (56) and (57) of IC3201.

3No Video 2 input sound: check the lines from

J3403 to pins (53) and (54) of IC3201.

4No Component input sound: check the lines

from J3404 to pins (50) and (51) of IC3201.

Are the audio signal outputs at pins (36)

(Rch) and (37) (Lch) of IC3201?

Is the collector signal of Q3403 at "L"?

Check the lines from between pins (36)

(Rch) and (37) (Lch) of IC3201 to pins (2)

(Rch) and (4) (Lch) of J3403.

No sound from monitor output

Check the line from pin (58) of IC2001 to

Q3403, as well as Q3401 and Q3402.

Check IC3201 and Its peripheral circuits.

No Audio Output

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