Read Sharp LC-30HV4E (serv.man10) Service Manual online
53
LC-30HV4E
No sound (1)
No sound (2)
A
VC System
No sound (3)
No sound is heard from the speaker in all modes.
Check audio circuits of the Display
.
Is the monitor audio output set to "V
ariable"? Or
Is the headphone connected?
Are the audio outputs of IC2501 (multi-sound
processor) in order?
Pins 36 and 37 of IC2501 (SC1 OUT
L/R).
Check IC2501 (multi-sound processor) and its
peripheral circuits.
Check lines and devices between pins 36/37 of
IC2501 and pins 1/3 of the
A
V
unit connector
(P2502). (Q2504-5, Q2509-10 and Q2513-4)
Set the monitor audio output to "Fixed".
Remove the headphone.
The speaker generates no sound when audio signals are inputted from an external device or a PC.
Check IC1301 (A
switch) and its peripherals.
Are the audio outputs of IC1301 (A
V switch) in
order?
Pins 52 and 54 of IC1301 (TV MAIN OUT
L/R)
Are the audio inputs of IC1301 (A
V switch) in
order?
Input 1: Between pins 2 and 4 of IC1301
Input 2: Between pins 9 and 1
1
of IC1301
Input 3: Between pins 16 and 18 of IC1301
Input 4: Between pins 23 and 25 of IC1301
PC input: Between pins 29 and 31 of IC1301
Are the audio input circuits of IC1301 (A
V switch)
in order?
Input 1: Between pins 6/2 and pins 2/4 of IC1301
Input 2: Between pins 6/2 and pins 9/1
1 of IC1301
Input 3:
Between pins 6/2 and pins 16/18 of IC1301
Front panel input: Between J2404 and pins 23/25
of IC1301
PC input: Between J2403 and pins 29/31 of IC1301
Are the audio inputs of IC2501 (multi-sound
processor) in order?
Pins 56 and 57 of IC2501 (SCI IN1 L/R)
YES
NO
YES
YES
YES
NO
NO
NO
No audio output <Input1>
No audio output <INPUT2/3>
Has the input mode been selected on the Input Select screen?
Are the audio outputs of IC2501 (multi-sound
processor) in order?
Pins 27 and 28 of IC2501 (DRCM L/R)
Check lines and devices between pins 27/28 of
IC2501 and pins 3/1 of INPUT1.
Also check the
audio mute circuits.
(IC2504, Q1
101-2)
Are the audio outputs of IC1301 (A
V switch) in
order?
Pins 43 and 45 of IC1301 (SC1
TV SUB OUT
L/R)
Check lines and devices between pins 43/45 of
IC1301 and pins 3/1 of INPUT2/3.
Also check
the audio mute circuits.
(IC1301, Q1
104-7 and Q1
109-12)
No monitor audio output or abnormal audio
The audio level is abnormal:
Is the monitor audio output set correctly?
"V
ariable" or "Fixed"
NO
YES
No sound at all:
Are the audio outputs of IC2501 (Multi-sound
processor) in order?
Pins 34 and 33 (SC2 OUT
L/R) of IC2501
Check lines and devices between pins 34/33 of
IC2501 and the monitor output (J1
101).
Also
check the audio mute circuit.
(Q2502-3, Q1
1
14-5 and Q1
106-7)
YES
Check peripherals of the SR unit DISPLA
Y
OUTPUT
2 pin (SC6000).
YES
YES
YES
YES
YES
Are audio signals applied to the
A
V
unit
connectors (pins 1 and 3 of P2502)?
YES
The speaker generates no sound when
TV signal is received.
Are the tuner audio inputs of IC2501 (multi-sound
processor) in order?
Pin 67 (sound IF1) of IC2501
Pin 69 (sound IF2) of IC2501
Is the audio signal applied to tuner output pin 21?
Check B.P
.F
. of SIF1 and SIF2.
(Q1
1
19-20 and Q1
121-2)
Check IC2501 (multi-sound processor) and its
peripheral circuits.
YES
YES
NO
NO
Check
TU1
101 (U/V tuner) and its peripherals.
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