LC-40D68UT
6 – 8
No audio (1)-2
INPUT-3 No audio.
Is INPUT-3 selected on the input select menu screen?
NO
Refer to “:No external input video [INPUT-3]”.
YES
Is the audio output selected for “VARIABLE” on the menu
screen?
NO
Set the audio output to “FIXED”.
YES
Does the audio signal come from pins (5) (L) and (4) (R) of input
terminal (J501) to pins (14) (L) and (5) (R) of IC503 (AUDIO
SWITCH)?
NO
Check the line between J501 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)?
NO
Check IC503/IC8001 and its peripheral circuits.
(IC502, Q509, Q510, etc.)
YES
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)
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)?
NO
Check the line between IC8001 and IC2701, and their peripheral
circuits (Q1306/Q1307, AMP_MUTE line, etc.).
YES
Is the audio output from IC2701 as specified?
NO
Check IC2701 and its peripheral circuits.
YES
Check the connector (P2701), speakers and their peripheral cir-
cuits.
