Service manual

41
LC-20B4U-S
LC-20B4U-B
TROUBLE SHOOTING TABLE (Continued)
No sound
from
speakers
Yes
No
Is pin (53) of
IC2001 at “L”?
Check all the settings on the microprocessor
’s adjust process menu.
No sound
No
Are outputs at
pins (1) and (7)
of IC3301/
IC3302/IC3303
as specified?
Yes
No
Are inputs at
pins (2) and (4)
as well as
outputs at pins
(8) and (12), all
of IC3305, as
specified?
Muting effect is
on. Check the
SP MUTE line.
Check IC3301,
IC3302, IC3303
and their
peripheral parts.
Yes
No
Are input and
output of
IC3304 as
specified?
Check IC3304
and its
peripheral parts.
Check the line
in question,
IC3301 and its
peripheral
parts.
Yes
Check the
speakers and
their peripheral
parts.
No sound
from
headphone
Check, J3303,
harness and
their peripheral
parts.
No sound
from output
line
Yes
No
Is pin (58) of
IC2001 at “L”?
No
Are outputs at
pins (14) and
(15) of IC3501
as specified?
Yes
Check the line
in question.
Check the
LMUTE line.
Check IC3501,
IC3304 and
their peripheral
parts.
TV sound
failure
Yes
No
Is output at Pins
(15) and (16) of
tuner as
specified?
No
Is input at pin
(67) of IC3304
as specified?
Yes
Check IC3304,
X3301 and
their peripheral
parts.
Check the
tuner and its
peripheral
parts.
Check Q3201,
Q3202 and
their peripheral
parts.