Read Sharp LC-20A2E (serv.man2) Service Manual online
LC-20A2E
15
TROUBLE SHOOTING TABLE
(Continued)
No sound
Check all the settins microprocessor's adjust process menu.
Is the pin 53 of
IC2001 in the
"L" state?
Is output at pins
26 and 27 of
IC901 normal?
Is output at pins
1 and 7 of
IC903 normal?
Yes
Yes
No
No
No
No
No
No sound
from front
speakers
Is output at pins
3 and 5 of
IC303 normal?
Yes
Is output at pins
8 and 12 of
IC3305 normal?
Yes
Muting effect is
on. Check the
FSMUTE line.
Check IC901
and their
peripheral parts.
Check IC903
and their
peripheral parts.
Check IC303
and their
peripheral parts.
Check IC3305
and their
peripheral parts.
Check front
speaker and
connection
cable.
Yes
Is the pin 53 of
IC2001 in the
"L" state?
Is output at pins
24 and 25 of
IC901 normal?
Is output at pins
1 and 7 of
IC304 normal?
Yes
Yes
No
No
No
No
No
Is output at pins
42 and 43 of
SC402 normal?
Yes
Is output at pins
6 and 7 of
P4004 normal?
Yes
Muting effect is
on. Check the
FSMUTE line.
Check IC901
and their
peripheral parts.
Check IC304
and their
peripheral parts.
Check SC402,
SC901 and their
peripheral parts
and connection.
Check P4004
and their
peripheral parts
and connection
cable.
Yes
Check the
J4001 line.
No sound
from
headphone
Is output at pins
36 and 37 of
IC901 normal?
Is output at pins
1 and 7 of
IC902 normal?
Check IC901
and their
peripheral parts.
Check IC902
and their
peripheral parts.
Yes
Yes
No
No
No sound
from output
line
TV sound
failure
Is output at pins
15 and 16 of
SC402 normal?
Is output at pins
17 and 18 of
W9 normal?
Check SC402,
SC901 and their
peripheral parts
and connection.
Check W9 and
their peripheral
parts and
connection.
Yes
No
No
Check the
U1 line.
Yes
Is output at pin
1 of W7 tuner
normal?
Is input at pin
67 of IC901
normal?
Check the tuner
and their
peripheral parts.
Check IC901,
MONOS/SIF
line and their
peripheral parts.
Yes
No
No
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