Sharp LC-70UD1U, Service Manual

Page: 63 / 84

LC-70UD1U
6 – 19
No monitor audio output
Is the audio output from the monitor set at “VARIABLE” or “FIXED” on the menu screen?
YES
NO
Check IC3301 (CPU) and its peripheral circuits.
Are there the audio signal outputs at pins (AN34) (HP_MONITOR_L) and (AN35) (HP_MONITOR_R) of IC3301 (CPU)?
YES
NO
Check IC3301 (CPU) and its peripheral circuits.
Does the audio signal come from pins (2) (MONI_HP_L) and (11) (MONI_HP_R) of IC1702 (Line-out Amplifier) to pins (3) (L) and (2) (R) of J504?
YES
NO
Check the line between IC1702 and J504 and their peripheral circuits.
Check the LINE_MUTE line and its peripheral circuits(Q506/Q510, etc).
Check the connector (J504) and their peripheral circuits, and speakers and the Cable.
No connect network
Does the signal come to 1pin of LAN-jack J9401?
(see fig-1, fig-2) NO Check the interface device and peripheral circuits.
(power-LED of hub, LINK-LED of hub)
YES
Does the signal come to AT18 pin of IC3301?
(see fig-2) NO Check the line between J9401 and IC3301.
Check the LAN-jack J9401.
YES
Check IC3303 and its peripheral circuits.
LAN-jack J9401 fig-1
1pin
fig-2