Read Sharp LC-28HM2E (serv.man2) Service Manual online
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.
