Read Sharp LC-30HV4E (serv.man10) Service Manual online
57
LC-30HV4E
No image (6)
A
VC System
No image when
TV signal is received
Check the PC I/F unit.
No teletext screen appears.
Is the video signal on tuner image output
pin 23?
Check peripherals of the tuner (TU1
101)
and replace if necessary
.
Is the video signal on pin 5 of IC1
106 (level
adj.) or
TP1
101?
Is the video signal applied to pin 63 of
IC1301 (A
V switch)?
Is the level control signal sent from pin 1 of
IC1
108 to pin 8 of IC1
103 (A
V switch)?
YES
No Monitor image <A
V
-OUT>
YES
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
Check lines and devices between pin 5 of
IC1
106 and pin 63 of IC1301.
Are the main video signal and sub video
signal sent from pin 30 of IC1301 and pin
44 of IC1301 respectively?
Check IC1301 (A
V switch) and its
peripheral circuits.
Is the teletext signal received (is a teletext-supporting receiver connected to the video input
terminal) and
TELETEXT
selected on the remote controller?
Select
TELETEXT
in an appropriate manner
.
Is the video signal applied to pin 21 of
IC1601 (teletext CPU)?
Check lines and devices between pin 56 of
IC1301 (A
V switch) and pin 21 of IC1601.
Is the text signal sent from pins 57, 58 and
59 of IC1601?
Check IC1601 and its peripheral circuits.
Is the text signal applied to pins 57, 53 and
55 of IC1401 (A
V switch)?
Check lines and devices between pins 57/58/59
of IC1601 and pins 57/53/55 of IC1301.
NO
YES
NO
NO
NO
NO
YES
YES
YES
YES
Is the video signal applied to pin 7 of IC401 (main comb filter) and pin 7 of IC402 (sub comb filter)?
<Main system>
Are the main
Y
and C signals applied to
pin 1 (TP812) and pin 48 of IC801 (main
video chroma) respectively?
Check lines and devices between IC4001
and IC801.
(IC403, Q415, etc.)
Are the main
Y
, Cb and Cr signals sent from pins
21, 22 and 23 of IC801 respectively?
Check IC801 (main video chroma) and its
peripheral circuits.
Are the main
Y
, Cb and Cr signals applied to pins
69, 68 and 67 of IC803 (RGB decoder)
respectively?
Check lines and devices between IC801 and
IC803. (IC814, Q814, Q815, etc.)
Are the main R, G and B signals sent from
pins 35, 37 and 39 of IC803 respectively?
Check IC803 (RGB decoder) and its
peripheral circuits.
Are the main R, G and B signals sent from
pins 19, 15 and 12 of FL810 respectively?
Is cutof
f frequency setting pin 17 of FL810
(6.7/30 MHz L.P
.F
.) pulled high?
Is the video signal sent from pin 4 of
IC1301 (A
V switch)?
YES
Check lines and devices between pin 41 of
IC1301 and monitor image output pin 20 (J1
101).
(Q1403 and Q1
113)
Check IC1301 and its peripheral circuits.
No monitor image <S-OUT>
YES
NO
NO
Are
Y
and C signals sent from pins 39 and
37 of IC1301 (A
V switch) respectively?
YES
Check lines and devices between pins
39/37 of IC1301 and monitor S-OUT
pins
3/4 (SC1
102).
(Q1401-2)
Check that input signal is S-INPUT
.
Check FL810 (6.7/30 MHz L.P
.F
.) and its
peripheral circuits.
Are the main R, G and B signals applied to
pins 3, 7 and 10 of FL810 (6.7/30 MHz
L.P
.F
.) respectively?
Check lines and devices between IC803
and FL810.(Q801-3 etc.)
Check lines and devices between IC1301
and IC401/402.
NO
NO
Check lines and devices between IC402
and IC802. (IC404, Q416-8, etc.)
Are the sub
Y
and C signals applied to pin
1 (TP813) and pin 48 (TP407) of IC802
(sub video chroma) respectively?
Are the sub
Y
, Cb and Cr signals sent from
pins 21, 22 and 23 of IC802 respectively?
Check IC802 (sub video chroma) and its
peripheral circuits.
YES
NO
Are the sub
Y,
Cb and Cr signals applied to Q901-2,
Q903-4 and Q905-6 (6.7 MHz L.P
.F
.) respectively?
Check lines and devices between IC802 and
Q901-2/Q903-4/Q905-6 (6.7 MHz L.P
.F
.).
YES
NO
Are the sub R, G and B signals sent from Q901-2,
Q903-4 and Q905-6 (6.7 MHz L.P
.F
.) respectively?
YES
Check the PC I/F unit.
Check Q901-2, Q903-4 and Q905-6 (6.7
MHz L.P
.F
.) and their peripheral circuits.
<Sub system>
No image (7)
Chec
k
IC1301 and its per
ipher
al circuits
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