Read Sharp LC-28HM2E (serv.man2) Service Manual online
44
LC-28HM2
AN-28SP2
TROUBLE SHOOTING TABLE
(Continued)
No sound
Ye
s
No
Does output icon show
headphone when volume
key is operated?
No sound from speaker
No
Is pin (15) of SC401 at
high level?
No
Check headphone plug
peripherals on front
terminal unit.
Check the peripherals
of speaker connector
terminal.
Ye
s
No
Does output icon show
lineout when volume key
is operated?
Monitor output in main menu is set to
"variable". Switch it to "fixed" or set video 3
to "input".
No
Ye
s
Are there normal outputs
at pins (52) and (54) of
IC401?
Check the peripherals
of IC401.
No
Ye
s
Are there normal outputs
at pins (1) and (7) of
IC306?
Check IC306 and its
peripherals.
Check rear terminal unit.
It is also possible that
display has problem.
No sound from headphone
No
Ye
s
Does output icon show
headphone when volume
key is operated?
Check headphone plug
peripherals on front
terminal unit.
Ye
s
Ye
s
Is pin (14) of IC505 at
high level?
Headphone is muted.
Check the peripherals
of IC505 and D306.
No
Ye
s
No
Are there normal audio
outputs from pins (7) and
(18) of IC301?
Is pin (9) of IC301 at
low level?
No
Ye
s
Is B of Q303 at high level?
Are there normal audio
inputs at pins (2) and
(23) of IC301?
No
Check the peripherals
of IC401.
Check IC307, Q309
and their peripherals.
Ye
s
Check C383 and the
peripherals of IC704.
Ye
s
Check the peripherals
of IC301.
No
Ye
s
Are there normal audio
outputs from pins (1) and
(7) of IC305?
Check the peripherals
of IC305.
Check the peripherals of
C2401 and C2402 on
front terminal unit.
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