Sharp LC-40D68UT Service Manual page 56

LC-40D68UT
INPUT-1 No audio.
Is INPUT-1 selected on the input select menu screen?
Refer to ":No external input video [INPUT-1]".
YES
Is the audio output selected for "VARIABLE" on the menu screen?
Set the audio output to "FIXED".
YES
Does the audio signal come from pins (5) (L) and (7) (R) of input
terminal (J509) to pins (12) (L) and (1) (R) of IC503 (AUDIO
SWITCH)?
Check the line between J509 and IC503.
YES
Does the audio signal come from pins (13) (L) and (3) (R) of IC503
to pins (B2) (L) and (A1) (R) of IC8001 (CPU)?
Check IC503/IC8001 and its peripheral circuits.
(IC502, Q509, Q510, etc.)
Check the audio signal lines between IC503 and
IC8001.
1) IC503: pin (13) (A_INL), pin (3) (A_INR)
2) SC501/SC601: pin (15), pin (14)
3) IC8001: pin (B12), pin (A1)
Check the audio switching signals (AUDIO_CTL0/1)
between IC503 and IC8001.
1) IC8001: pin (L1) (AUDIO_CTL0), pin (K1)
(AUDIO_CTL1)
2) SC1101/SC1201: pin (17), pin (18)
3) Q510: pin (2), Q509: pin (2)
4) IC503: pin (10), pin (9)
YES
Does the audio signal come from pins (C4/A3) (SPOUT_L/R) of IC8001 (CPU) to
pins (3) (INLP), and (7) (INRP) of IC2701 (AMP)?
YES
Is the audio output from IC2701 as specified?
YES
Check the connector (P2701), speakers and their peripheral circuits.
No audio (1)-1
NO
NO
NO
NO
6 – 7
INPUT-2 No audio.
Is INPUT-2 selected on the input select menu screen?
Refer to ":No external input video [INPUT-2]".
YES
Is the audio output selected for "VARIABLE" on the menu screen?
Set the audio output to "FIXED".
YES
Does the audio signal come from pins (2) (L) and (4) (R) of input terminal
(J505) to pins (15) (L) and (2) (R) of IC503 (AUDIO SWITCH)?
Check the line between J505 and IC503.
YES
Does the audio signal come from pins (13) (L) and (3) (R) of IC503 to pins
(B2) (L) and (A1) (R) of IC8001 (CPU)?
Check IC503/IC8001 and its peripheral circuits.
(IC502, Q509, Q510, etc.)
Check the audio signal lines between IC503 and IC8001.
1) IC503: pin (13) (A_INL), pin (3) (A_INR)
2) SC501/SC601: pin (15), pin (14)
3) IC8001: pin (B12), pin (A1)
Check the audio switching signals (AUDIO_CTL0/1) between
IC503 and IC8001.
1) IC8001: pin (L1) (AUDIO_CTL0), pin(K1) (AUDIO_CTL1)
2) SC1101/SC1201: pin (17), pin (18)
3) Q510: pin (2), Q509: pin (2)
4) IC503: pin (10), pin (9)
YES
NO Check the line between IC8001 and IC2701, and
their peripheral circuits (Q1306/Q1307,
AMP_MUTE line, etc.).
NO Check IC2701 and its peripheral circuits.
NO
NO
NO
NO