LC-37GA9EK (serv.man8). Troubleshooting Tables - Sharp TV Service Manual (repair manual)

lc-37ga9ek (serv.man8) service manual
Model
LC-37GA9EK (serv.man8)
Pages
12
Size
190.63 KB
Type
PDF
Document
Service Manual
Brand
Device
TV / LCD / Troubleshooting Tables
File
lc-37ga9ek-sm8.pdf
Date

View Sharp LC-37GA9EK (serv.man8) Service Manual online

32
 LC-26GA5E
 LC-32GA5E
  LC-32GA9E/LC-32BV9E
  LC-37GA9E/LC-37BV9E
TROUBLESHOOTING TABLE
28
LC-32/37GA9E
LC-32/37BV9E
TROUBLESHOOTING TABLE
NO
YES
NO
YES
YES
NO
YES
YES
Power unit operation check
Are the power cord and harness in the unit properly connected?
Are both ends of C704 and C705 (32"/37") / C707 (26") short-
circuited when checking their resistance values?
Connect the power cord and harness properly, and turn on the 
power.
Is a voltage of BU5V applied to pin (20) of P701? (Set the main 
power SW to OFF.)
C704 ••• Check VA701, VA702 and D701.
C705/C707 ••• Check IC704 and 705.
Is F701 normal?
Does the same symptom appear even if R858 (2.7k) is removed 
and the power is supplied again?
Is a voltage of approx. 8 – 15V to pin (4) of IC705?
NO
Replace F701.
YES
Check short circuit of 5V line (D737, C752, etc.).
NO
Check IC705, IC708, D725 
and Q724.
NO
Check IC704, D728, D762 and D736. If there are no problems, 
check the resistance value between pins (1) and (6) of P704. 
When the value is low (several 
Ω- several hundred Ω),
disconnect P704. If the value is still low, the parts of 24V line are 
defective. When the resistance value is several k
Ω, check the 
inverter unit.
YES
Check Q724, D731, D734, IC707, D751, D753, D754, D741, 
D759 and D746.
Does a relay noise sound? (Once)
YES
NO
Check peripheral circuits of D738, R828 and D735.
NO
Are PCON1 and 2 [pins (1) and (2) of P702] at Hi (3V or more)?
NO
There is a possibility that control by P-CON is not performed 
properly. Check whether the "PS-ON" and "PS-ON2" signals are 
sent from pins (19) and (15) of IC1710 (FPGA) of MAIN-UNIT.
YES
Check peripheral circuits of Q712, Q713, Q721, Q723 and 
RY701.
Is it a symptom that the relay clatters twice as soon as the main 
power SW is set to ON and the power is not supplied?
33
 LC-26GA5E
 LC-32GA5E
  LC-32GA9E/LC-32BV9E
  LC-37GA9E/LC-37BV9E
Troubleshooting Table (continued)
29
LC-32/37GA9E
LC-32/37BV9E
TROUBLESHOOTING TABLE
 (Continued)
No sound (1) (during the reception of TV broadcasting)
No audio output during UHF/VHF reception
Checklist:
1) Is the volume set to MIN or MUTE on the remote control? ••• Set the desired volume.
2) Are headphones connected to HEADPHONE (J1301)? ••• Disconnect them.
3) Is ANT-CABLE disconnected or connected improperly? ••• Connect it correctly as per the operation manual.
NO
Is the audio signal (L/R) sent from pins (28) and (27) of IC3002 
(VCT)?
NO
YES
Is the audio signal of pins (3) 
and (5) of IC303 (OP-AMP) 
sent properly?
(AV-UNIT)
(TUNER)
Check IC303 or peripheral 
circuits.
NO
YES
YES
Is the audio signal of pin (4) 
of IC301/IC302 (AUDIO-
AMP) sent properly?
Check HEAD-PHONE 
(J1301) or peripheral 
circuits.
NO
Is the audio signal output of 
pins (2) and (4) of P301 
(AUDIO-CONNECTOR) 
normal?
YES
Check SP-BOX (right and 
left) and wire harness.
Check P301 (AUDIO-
CONNECTOR) and 
peripheral circuits.
YES
NO
Is the audio signal (SIF) sent 
from pin (1) of CONNECTOR 
(SC2705)?
Check pin (31) of IC3002 
(VCT) and peripheral 
circuits.
YES
Is the SIF signal (SIF_IN1+) 
sent to pin (31) of IC3002 
(VCT)?
Check whether +5V and +8V 
are supplied to pins (18) and 
(33) of IC3002 respectively.  
Or, check peripheral circuits.
YES
NO
NO
NO
NO
Is the audio signal (SIF) sent 
from pin (12) of IC201 (IF-
DEMOD)?
Check Q203 (AMP) and 
peripheral circuits.
YES
Is the SIF signal sent to pins 
(23) and (24) of IC201 (IF-
DEMOD)?
Check IC201 and peripheral 
circuits.
YES
Is the IF signal sent from pin 
(8) of TUNER (TU201)?
Check FL202 and peripheral 
circuits.
YES
Check whether 33V and 5V 
are supplied to pins (9) and 
(7) of TUNER (TU201) 
respectively. Check SDA/SCL 
and AGC signal.
Replace TUNER (TU201).
34
 LC-26GA5E
 LC-32GA5E
  LC-32GA9E/LC-32BV9E
  LC-37GA9E/LC-37BV9E
Troubleshooting Table (continued)
30
LC-32/37GA9E
LC-32/37BV9E
No sound from external input devices (2)
No sound from an external 
input device connected to 
EXT1 (SCART1).
No sound from an external 
input device connected to 
EXT2 (SCART2).
No sound from an 
external input device 
connected to EXT3.
No sound from EXT4 
(AUDIO) connecting an 
external input device.
No sound from EXT5 
(AUDIO) connecting an 
external input device.
YES
<EXT1>
Is IN1-L audio signal sent 
from pin (6) of SCART1 
terminal (J1101) to pin 
(14) of IC3002 (VCT)?
Is IN1-R audio signal sent 
from pin (2) of SCART1 
terminal (J1101) to pin 
(13) of IC3002 (VCT)?
<EXT2>
Is IN2-L audio signal sent 
from pin (27) of SCART2 
terminal (J1101) to pin 
(12) of IC3002 (VCT)?
Is IN2-R audio signal sent 
from pin (23) of SCART2 
terminal (J1101) to pin 
(11) of IC3002 (VCT)?
<EXT3>
Is IN3-L audio signal 
sent from pin (3) of 
J1201 terminal to pin 
(16) of IC3002?
Is IN3-R audio signal 
sent from pin (5) of 
J1201 terminal to pin 
(15) of IC3002?
Is the audio signal 
properly sent from pins 
(28) and (27) of IC3002?
Check IC3002 or 
peripheral circuits.
Is the audio signal of 
pins (7) and (1) of IC303 
(OP-AMP) sent properly?
Check IC303 or 
peripheral circuits.
<EXT4>
Is D-SUB-L audio signal 
sent from J2702 to pin 
(15) of IC2704?
Is D-SUB-R audio signal 
sent from J2702 to pin 
(2) of IC2704?
Is D-SUB-L audio signal 
sent to pin (10) of 
IC3002?
Is D-SUB-R audio signal 
sent to pin (9) of 
IC3002?
<EXT5>
Is HDMI-L audio signal 
sent from J2701 to pin 
(14) of IC2704?
Is HDMI-R audio signal 
sent from J2701 to pin 
(5) of IC2704?
Check pins (6) and 
(2) of SCART1 and 
connection to an 
external input 
device.
Check pins (27) and 
(23) of SCART2 and 
connection to an 
external input 
device.
Check pins 3 
(J1201) and 5 
(J1201) of EXT3 
and connection to 
an external input 
device.
Is HDMI-L audio 
signal sent to pin 
(10) of IC3002?
Is HDMI-R audio 
signal sent to pin (9) 
of IC3002?
Is the audio output 
signal of pins (13) and 
(16) of IC302/IC301 
(MAIN-AMP) normal?
Check IC302/IC301 
(MAIN-AMP),
HEADPHONE and 
peripheral circuits.
Check CONNECTOR 
(P301) and SP-BOX 
(right and left).
YES
YES
NO
NO
Check output of pins 
(13) and (3) of 
IC2704 and 
peripheral circuits.
NO
Check that Option-
HDMI Setup-Audio 
select is set to 
"Analog".
YES
YES
YES
OK
NO
YES
YES
YES
NO
YES
NO
NO
TROUBLESHOOTING TABLE
 (Continued)
35
 LC-26GA5E
 LC-32GA5E
  LC-32GA9E/LC-32BV9E
  LC-37GA9E/LC-37BV9E
Troubleshooting Table (continued)
31
LC-32/37GA9E
LC-32/37BV9E
TROUBLESHOOTING TABLE
 (Continued)
No sound except from speakers (3)
Check audio input signal of pin (31) of IC3002 (VCT), pins (18) 
and (33) of the power line, pins (84) and (83) of I2C-LINE, and 
peripheral circuits.
NO
NO
NO
NO
No audio output from the 
headphones
No audio output from EXT1 
(SCART) terminal.
NO
Is there audio output on pins 
(2) and (3) of the headphone 
terminal (J1301)?
Checklist:
1) Is the MUTE button on the remote control set to ON? ••• Set to OFF.
2) Check the connection to external devices. ••• Is there any improper connection?
Is audio input/output signal of 
pins (3) and (5)/(1) and (7) of 
IC303 (OP-AMP) normal?
NO
NO
YES
YES
NO
YES
NO
NO
NO
YES
YES
Is audio output signal (SPK-
OUT L/R) properly sent from 
pins (28) and (27) of IC3002 
(VCT)?
Check the connection to 
EXT1 (J1101) and external 
devices.
Check the connection to 
EXT2 (J1101) and external 
devices.
Is S-MUTE-LINE [IC1710 (pin 
21)] or S2-MUTE-LINE 
[IC3003 (pin 26)] at H?
(Check Q1102/Q1101 
operation.)
Is audio signal sent from pins 
(22) and (21) of IC3002?
Check the audio signal 
output line from pins (22) and 
(21) of IC3002 to 
Q1103/Q1104/Q1201/Q1202
Check the connection to 
AUDIO OUTPUT terminal 
(J1201) and external devices.
Is S-MUTE-LINE [IC1710 (pin 
21)] at H?
(Check Q1204/Q1203 
operation.)
Is audio signal sent to pins 
(3) and (1) of EXT1 (J1101)?
Is S-MUTE-LINE [IC1710 
(pin 21)] at H?
(Check Q1106/Q1105 
operation.)
Is audio signal sent from 
pins (24) and (23) of 
IC3002?
Check the audio signal 
output line from pins (24) 
and (23) of IC3002 to pins 
(3) and (1) of EXT1.
Check the power supply 8/5 
V pins (18) and (33) of 
IC3002 and peripheral 
circuits.
Is audio signal sent to pins 
(24) and (22) of EXT2 
(J1101)?
Is audio signal sent to pins 
(13) and (15) [L/R (white) 
(red)] of AUDIO OUTPUT 
terminal (J1201)?
No audio output from EXT2 
(SCART) terminal.
No audio output from AUDIO 
OUTPUT terminal.
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