Sharp LC-28HM2E (serv.man2) Service Manual ▷ View online
45
LC-28HM2
AN-28SP2
TROUBLE SHOOTING TABLE
(Continued)
No sound
No sound
No
Are there normal audio outputs
from pins (38) and (40) of
IC401?
No line output
Check the peripherals of IC401.
No
Ye
s
Check the peripherals of IC302.
Check the peripherals of IC704.
No
No color production regardless of
color system change
No
Color production with NTSC, but
no color with PAL and SECAM
No
No color production only with
PAL
No color production only with
SECAM
Check the peripheral circuits of IC801 (iX3323CE).
Check the peripheral circuits of
IC2802 (TA1229N).
Ye
s
No
Are there normal audio outputs
from pins (10) and (16) of
IC302?
Are pins (5) and (7) of IC302
at low level?
Ye
s
No
Are there normal audio outputs
from pins (1) and (7) of IC304?
Check the peripherals of
IC304.
Ye
s
No
Is pin (5) of IC505 at low level?
Check IC505.
Ye
s
Check the peripherals of IC505,
IC303, Q306, Q301, Q302, Q309
and IC307.
No component and PC signals output
Check the peripherals of
IC410, Q407, Q408 and
IC401.
46
LC-28HM2
AN-28SP2
TROUBLE SHOOTING TABLE
(Continued)
No color
Ye
s
No
No
No
No
No
No
No
No
No
No color production of video line and component
line signals
Ye
s
Is 3.58MHz supplied to
pin (10) of IC801?
Check X801 and its
peripherals.
Ye
s
Are there normal
outputs at pins (3) and
(6) of IC406?
Check the peripherals
of IC7001 and IC7002.
Ye
s
Ye
s
Ye
s
Is there normal input at
pin (13) of IC801?
Check the peripherals
of IC801 and IC7003.
No
Are there normal outputs at
pins (5) and (6) of IC801?
Check input and output of IC406.
Check the peripherals
of IC801.
Check the peripherals.
Ye
s
Are there normal inputs
at pins (51) and (52),
and normal outputs at
pins (42), (42) and (43)
of IC801?
Check IC801 and its
peripherals.
Are there normal inputs
at pins (1), (5) and (9),
and normal outputs at
pins (3), (7) and (11) of
P803?
Check RGB filter unit
unit (KA266N).
No color production of video line signals
(Commonly supplied between IC401 and IC801.)
Is there normal output at pin (83) of IC7001?
Ye
s
Ye
s
Ye
s
Is there normal output
at pin (53) of IC401?
Check IC401 and the
peripherals of IC802.
Check the line from rear terminal unit in
the case of V1(S), and the line from front
terminal board in the case of V2(S).
No color production only
with video S signals
Is there normal output
at pin (58) of IC401?
Is there normal input at
pin (5) or (12) of IC401?
Ye
s
No color production of component line signals
Ye
s
Are there normal inputs
at pins (4), (7) and (9)
of IC416 and IC417?
Check the related part
of the rear terminal
unit.
Ye
s
Is there normal output
at pin (8) of IC416 and
IC417?
Check IC416, IC417
and the peripherals of
IC404 and IC405.
Ye
s
Video signals are properly
supplied to SC503, but no
color production.
Check if "Monochrome"
setting is in effect.
The term "video composite" denotes video 1, video 2 and video 3 signals.
The term "video S" denotes video 1 (S video input) and video 2 (S video input) signals.
The term "video line" denotes the aggregate of "video composite" and "video S" signals.
The term "component line" denotes component 1 and component 2 signals.
47
LC-28HM2
AN-28SP2
TROUBLE SHOOTING TABLE
(Continued)
No picture
Ye
s
No
No picture of video line and component line
signals
Are there normal outputs at
pins (3), (5) and (6) of IC406?
Check IC406 and its
peripherals.
Ye
s
No
Are there normal inputs at pins
(51), (52) and (53) of IC801?
Check the peripherals.
Ye
s
No
Are there normal outputs at pins
(41), (42) and (43) of IC801?
Check IC801 and its
peripherals.
Ye
s
No
Are there normal outputs at
pins (3), (7) and (11) of IC803?
Check RGB filter unit
(KA266N).
Ye
s
No
Are there signals at pins (1),
(2), (11), (12), (15), (16), (25)
and (26) of SC1408?
Ye
s
It is possible that display is
in trouble.
It is possible that PC I/F unit
(CPCi-0040CE) is in trouble.
Ye
s
No
No picture of video line signals
Are there normal
input/output on IC401?
Check IC401 and its
peripherals.
Ye
s
No
Are there normal outputs at
pins (83) and (84) of IC7001?
Check IC7001, IC7002 and
their peripherals.
Ye
s
No
Is there normal input at pin
(1) of IC407?
Check IC407 and the
peripherals of IC7003.
Ye
s
No
Are there normal inputs at
pins (13) and (15) of IC801?
Check IC407 and the
peripherals of IC801.
Ye
s
No
Are there normal outputs at
pins (4), (5) and (6) of IC801?
Check IC801 and its
peripherals.
No picture depending on color
system
Check the peripheral circuits of
IC801 (iX3323CE).
48
LC-28HM2
AN-28SP2
TROUBLE SHOOTING TABLE
(Continued)
No picture
No picture of component line and PC line signals
No synchronization
No
Is there normal signal input at pin
(8) of IC403, IC404 and IC405?
Check IC403, IC404, IC405 and
their peripherals.
Ye
s
Check IC415, IC416,
IC417 and their
peripherals.
No
PC line
Component line
Is there normal signal output at pin
(2) of IC403, IC404 and IC405?
Ye
s
No
Is there normal signal output at pin
(9) of IC403, IC404 and IC405?
Ye
s
No
Check the peripherals of
IC406.
AV line
PC line
Ye
s
No monitor output
No
No
Is there normal video output
at pin (41) of IC401?
Check the peripherals of
IC401.
No
Is pin (5) of IC505 at low
level?
Check IC505.
No
Check the peripherals of
IC505 as well as those of
IC303, Q306, Q401, Q402,
Q403, Q404 and Q405.
Are there H/V sync signals
outputs at pins (15) and (22)
of IC1901?
No
Check the peripherals of
IC1901, pin (18) of IC801,
and the peripherals of IC406.
Ye
s
Is there proper
synchronization between the
H/V sync signals at pins (15)
and (22) of IC1901 and the
video output signals at pins
(41), (42) and (43) of IC801?
No
Check pins (3), (4) and (21)
of IC1901, and the
peripherals of IC406.
Ye
s
Check IC418, IC419, IC420
and their peripherals.
It is possible that PC I/F unit
(CPCi-0040CE11) is in
trouble.
