Read Sharp LC-37GA3E (serv.man8) Service Manual online
36
LC-32GA3E
LC-37GA3E
LC-37GA3E
TROUBLE SHOOTING TABLE
(Main) Power
Seine
Main
Monitor microprocessor
Backup
Triac
PS ON
NO
NO
NO
NO
NO
NO
NO
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
<Power supply>
No power supply (Front LED is off) or no power-up (Front LED does not change from red to green)
Is the power supply cord properly connected to the main unit?
Reconnect the power supply cord and turn on the power
Are F1701, F1702, and F1703 normal?
Replace F1701, F1702, and F1703, and then turn on the
power. If a fuse still blows, replace Z1701 , Z1702, D1701,
TRA1701 , D1702, D1703 and D2703.
power. If a fuse still blows, replace Z1701 , Z1702, D1701,
TRA1701 , D1702, D1703 and D2703.
Is the output voltage of BU+6V Iine (pin 5 of DP terminal)
normal?
normal?
In stand-by, is a voltage of about 170 V applied to C3701 ?
Check the oscillation side (primary side) and the
commutation side (secondary side) of the BU5V system
power supply circuit.
commutation side (secondary side) of the BU5V system
power supply circuit.
Is there any broken part or short-circuit on BU6V Iine?
Remove the broken part or short-circuit and check again.
Are the wire harness, FFC, etc. in the set connected properly?
Reconnect the wire harness, FFC, etc. and check again.
Is a voltage of about 380 V applied to C4701 and C5701 when
power is turned on?
power is turned on?
Check the 380V system power supply circuit. (L2701~3,
IC2701~2, Q2701~8, D2701~2, D1704, PC2701, etc.)
IC2701~2, Q2701~8, D2701~2, D1704, PC2701, etc.)
Is a voltage of 15 V applied to both inverter lines (INV_15V-1
and INV_15V-2) after power is turned on?
and INV_15V-2) after power is turned on?
Check the oscillation side (primary side) and the commutation
side (secondary side) of each power supply circuit for the
inverters (INV_15V-1 and INV_15V-2).
side (secondary side) of each power supply circuit for the
inverters (INV_15V-1 and INV_15V-2).
Are all power supply circuits for DC/DC converter output
normal?
normal?
Check the oscillation side (primary side) and the commutation
side (secondary side) of each power supply circuit for DC/DC
converters
side (secondary side) of each power supply circuit for DC/DC
converters
Check or replace DCIDC converters and lines.
URB6V (IC6753)
BS10V (IC6752)
UR19V (IC5752)
UR6V / 5V (IC6754 / IC3752)
1.8 V / 3.3 V / 35 V (lC6756)
URB6V (IC6753)
BS10V (IC6752)
UR19V (IC5752)
UR6V / 5V (IC6754 / IC3752)
1.8 V / 3.3 V / 35 V (lC6756)
• Power switch: Top panel
(Main) Power (DC cutoff: Detected by microprocessor)
[Scheme of power supply system]
(Main) Power (DC cutoff: Detected by microprocessor)
[Scheme of power supply system]
[(Main) Power OFF sequence]
1) (Main) Power OFF (DC switch)
2) (Main) Power shutoff is detected by the monitor microprocessor port
3) Standby request (power cord) is sent to Seine from microprocessor.
4) Seine shutdown process
5) Reception of shutdown permission from Seine
6) Monitor microcomputer turns off the relay to enter the standby mode
1) (Main) Power OFF (DC switch)
2) (Main) Power shutoff is detected by the monitor microprocessor port
3) Standby request (power cord) is sent to Seine from microprocessor.
4) Seine shutdown process
5) Reception of shutdown permission from Seine
6) Monitor microcomputer turns off the relay to enter the standby mode
37
LC-32GA3E
LC-37GA3E
LC-37GA3E
TROUBLE SHOOTING TABLE
(Continued)
NO
NO
NO
NO
NO
NO
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
No sound comes out (1)
No sound comes out at UHF/VHF reception.
Is the SIF output from the tuner as specified?
(TU1
101 Pin 7)
Check
TU1
101 (UV tuner) and its peripheral
circuits.
Is the input signal to pin (67) (ANA_lN1+) and
pin (69) (ANA_lN2+) of IC2701
(MUL
TI_SOUND_PROCESSOR) as specified?
Check the peripheral circuits of filter circuits
(Q1
121 -2) (Q1
1
19-20).
Are the audio signals from pins (34) and (33)
(SC2_OUTL/R) of IC2701 to pins (32) and (33)
of IC2714 (DIR) as specified?
Check the lines from pins (34) and (33)
(SC2_OUTL/R) of IC2701 to pins (32) and (33)
(DIR) of IC2714.
Are the audio outputs (A-OUT_L/R) from pins
(28) and (29) of IC2714 as specified?
Are signals LRCK, BICK, SDT
O and SDTI
inputted/outputted from IC2714 to IC2710
(DSP) normally?
Are the audio outputs from pins (28) and (29)
of IC2714 to pins (13) and (15) of P3801 (1-bit
amplifier input) as specified?
Check IC2714 and its peripheral circuits.
Check the lines from pins (28) and (29) of
IC2714 to pins (13) and (15) of P3801 (1-bit
amplifier input). (IC3802, Q3805-6,8)
Is the signal from the 1-bit amplifier inputted to
each terminal of P3810?
Check the 1-bit amplifier and its peripheral
circuits.
Is relay normally switched from R
Y3801
(speaker switching) of the
A
V
PWB ?
No external input sound comes out.
<INPUT
-1>
Is the L-ch audio signal inputted from pin (6) of input terminal SC1
101 to pin (2) of IC3801 ?
Is the R-ch audio signal inputted from pin (2) of input terminal SC1
101 to pin (4) of IC3801 ?
<lNPUT
-2>
Is the L-ch audio signal inputted from pin (6) of input terminal SC1
102 to pin (9) of IC3801 ?
Is the R-ch audio signal inputted from pin (2) of input terminal SC1
102 to pin (1
1) of IC3801 ?
<lNPUT
-3>
Is the L-ch audio signal inputted from pin (6) of input terminal SC1
103 to pin (16) of IC3801 ?
Is the R-ch audio signal inputted from pin (2) of input terminal SC1
103 to pin (18) of IC3801 ?
<lNPUT
-4>
Is the L-ch audio signal inputted from pin (8) of input terminal J141 to pin (23) of IC3801 ?
Is the R-ch audio signal inputted from pin (4) of input terminal J142 to pin (25) of IC3801 ?
< INPUT
-5>
Is the L-ch audio signal inputted from pin (2) of input terminal J1900 to pin (29) of IC3801 ?
Is the R-ch audio signal inputted from pin (3) of input terminal J1900 to pin (31) of IC3801 ?
Is the L-ch audio signal outputted to pin (52) of IC3801 ?
Is the R-ch audio signal outputted to pin (54) of IC3801 ?
Are the audio signals inputted to pins (56) (L-ch) and (57) (R-ch) of IC2701 ?
38
LC-32GA3E
LC-37GA3E
LC-37GA3E
YES
YES
YES
NO
NO
No sound comes out from the headphones.
Check IC2714 and its peripheral circuits.
Check the mute control terminal pin (2) of
IC2702.H:
Active, L: Mute
Are audio output pins (26) and (27) of IC2714
(DIR) as specified?
Are audio output pins (1) and (7) of IC2702
(H/P_AMP) as specified?
Check J2402 (HEAD_PHON_JACK) and its
peripheral circuits.
NO
NO
YES
YES
YES
No sound comes out. (2)
No sound comes out. (3)
Are audio output pins (37) and (36)
(SC1_OUT_L/R) of IC2701 (MUL
TI_SOUND_
PROCESSOR) as specified?
Are audio output pins (7) and (1) of IC2704
(EQ_AMP) as specified?
No monitor audio output comes out.
Is the monitor audio output set to anything other
than "V
ariable"?
Are the headphones disconnected?
Check IC2701 and its peripheral circuits.
Check IC2704 and its peripheral circuits.
NO
YES
Are there audio signal inputs at pins (5) and
(14) of IC1
1
10 (AUDIO_SW)?
Check between IC2704 and IC1
1
10.
NO
YES
Are audio output pins (3) and (13) of IC1
1
10
(AUDIO_SW) as specified?
Is the control signal at pin (10) of IC1
108 as
specified?
YES
Check between IC1
1
10 and
AUDIO OUTPUT
terminal.
Check IC1
108 and its peripheral circuits.
YES
TROUBLE SHOOTING TABLE
(Continued)
39
LC-32GA3E
LC-37GA3E
LC-37GA3E
TROUBLE SHOOTING TABLE
(Continued)
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
NO
NO
YES
YES
YES
YES
YES
YES
NO
NO
<Signals>
<CVBS,
Y/C, S-VIDEO signal> input
No VIDEO output (1)
External input in trouble <lNPUT
-1>
Is Input1 selected in the input switching
menu screen?
Select Input1 and the input signal in
the input switching menu screen .
Is there VIDEO signal input at each VIDEO
input terminal of IC3801 (A
V SWITCH)?
(CVBS signal input)
Check between pin (20) of SC1
101
and pin (1) of IC3801.
External input in trouble <INPUT
-2>
Is Input 2 selected in the input switching menu
screen?
Select Input 2 and the input signal in the
input switching menu screen.
Is there VIDEO signal input at each VIDEO
input terminal of IC3801 (A
V SWITCH)?
(Y/C VIDEO signal input)
Are there
Y
and C signals input at pins (10) and (12)?
(CVBS signal input)
Is there VIDEO signal input at pin (8) ?
(CVBS signal input)
Check between pin (20) of SC1
102 and
pin (8) of IC3801 .
(Y/C VIDEO signal input)
Check between pins (20) and (15) of
SC1
102 and pins (10) and (12) of IC3801.
External input in trouble <INPUT
-3>
Is Input 3 selected in the input switching menu
screen?
Select Input 3 and the input signal in the
input swltching menu screen.
Is there VIDEO signal input at each VIDEO
input terminal of IC3801 (A
V SWITCH)?
(CVBS signal input)
Is there VIDEO signal input at pin (15)?
(Y/C VIDEO signal input)
Are there
Y
and C signals input at pins (17) and (19)?
(CVBS signal input)
Check between pin (20) of SC1
103 and
pin (15) of IC3801.
(Y/C VIDEO signal input)
Check between pins (20) and (15) of
SC1
103 and pins (17) and (19) of IC3801.
External input in trouble <lNPUT
-4>
Is Input 4 selected in the input switching menu
screen ?
Select Input 4 and the input signal in the
input switching menu screen.
Check IC3801 (A
V SWITCH) and the peripheral circuits.
Is there VIDEO signal input at each VIDEO input
terminal of IC3801 (A
V SWITCH)?
(S-VIDEO signal input)
Are there
Y
and C signals input at pins (24) and (26)?
(VIDEO signal input)
Is there VIDEO signal input at pin (22) ?
(VIDEO signal input)
Check between pin (2) of J142 and pin (22)
of IC3801.
(S-VIDEO signal input)
Check between pins (3) and (4) of J141 and
pins (24) and (26) of IC3801.
(CVBS, VIDEO Signal Input) :
Are there MAIN VIDEO signal output at pin (56) of IC3801 and SUB VIDEO signal output at pin (44)?
(Y/C, S-VIDEO Signal Input):
Are there MAIN-Y
signal output at pin (56) of IC3801 , MAIN-C signal output at pin (58), SUB-Y
sig
nal output at pin (44) and SUB-C signal output at pin (47)?
(CVBS, VIDEO Signal Input) :
Are there VIDEO signals input at pin (8) of IC401 (MAIN L.P
.F
.) and pin (2) of IC600 (SUB L.P
.F
.)?
(Y/C, S-VIDEO Signal Input) :
Are there MAIN-Y
and MAIN-C signals input at pins (8) and (1
1) of IC401.
Are there SUB-Y
and SUB-
C signals input at pins (2) and (6) of IC600?
<MAIN>
3D-YIC (P
AL)
(CVBS, VIDEO signal input)
Is there VIDEO signal input at pin (8) of
IC402 (MAIN 3D-YC & CHROMA) ?
(Y/C, S-VIDEO signal input)
Are there
Y
and C signals input at pins (8) and
(18) of IC402 (MAIN 3D-YC & CHROMA) ?
Check between IC401 and IC402.
Are there digital VIDEO signal outputs at
pins (124)-(133) and (140)-(159) of IC402?
Check IC402 and the peripheral circuits
<MAIN>
2D-Y/C (SECAM)
(CVBS, VIDEO signal input)
Is there VIDEO signal input at pin (12) of
lC502 (MAIN 2D-YC & CHROMA) ?
(Y/C, S-VIDEO signal input)
Are there
Y
and C signals input at pins (12) and
(16) of IC5O2 (MAIN 2D-YC & CHROMA) ?
Check between IC401 and IC502.
Are there digital VIDEO signal outputs at
pins (1
15)-(126) and (133)-(144) of IC502?
Check IC502 and the peripheral circuits.
<SUB>
(CVBS, VIDEO signal input)
Is there VIDEO signal input at pin (72) of
IC601 (SUB 2D-YC & CHROMA) ?
(Y/C, S-VIDEO signal input)
Are there
Y
and C signals input at pins (72)
and (71) of IC601 (SUB 2D-YC & CHROMA) ?
Check between IC401 and IC601.
Are there digital VIDEO signal outputs at
pins (31)-(40) and (41)-(50) of IC601 ?
Check IC601 and the peripheral circuits.
Check between IC3801 and
IC401/IC600.
Are there digital VIDEO signal inputs at pins (53), (54), (57)-(60), (51), (52) (RE0-7), pins(63)-(68), (61), (62) (GE0-7), pin
s (73)-(78), (69), (70) (BE0-
7), pins (81)-(86), (79), (80) (RO0-7), pins (91)-(96), (89), (90) (GO0-7), pins (99), (100), (1), (2), (5), (6), (97), (98) (B
O0-7), and pins (7)-(10)
(HSYNC, VSYNC, DE, CLKIN) of IC3201 (L
VDS
TRANSMITTER)?
Replace the main PWB, or check between
IC402/C502/lC601 and IC3201.
Are there digital VIDEO signal outputs at pins (49)(T
A1-), (48)(T
A1+), (47)(TB1 -), (46)(TB1 +), (44)(TC1 -), (43)(TC1 +),(41)(
TCLK-), (42)(TCLK+),
(40)(TD1 -), (39)(TD1+), (37)(T
A2-), (36)(T
A2+), (35)(TB2-), (34)(TB2+), (32)(TC2-), (31)(TC2+), (30)(TCLK2-),(29)(TCLK2+), (28
)(TD2-) and
(27)(TD2+) of IC3201?
Check IC3201 (L
VDS_TRANSMITTER)
and the peripheral circuits.
Check the LCD CONTROL
PWB.
(CVBS signal input)
Is there VIDEO signal input at pin (1) ?
