LC-37GA9EK (serv.man8). Troubleshooting Tables - Sharp TV Service Manual (repair manual). Page 5

No picture appears on LCD during the tuner (U/V) reception.

Checklist:
1) Is "INPUT SOURCE" button        on the remote control set up correctly? ••• See the operation manual and set "INPUT SOURCE" to "TV".
2) Is MENU-PICTURE-Contrast/Brightness set to "MIN"? ••• Set it to an appropriate level.
3) Is ANT-CABLE disconnected or connected improperly? ••• Connect it correctly as per the operation manual.

Is level of pins (4) and (5) of 
tuner (TU201) and pins (10) 
and (11) of IC201 (IF-
DEMOD) at H?

These are communications 
lines for control (I2C). Follow 
the path and check whether 
they are forced to L 
(PULL_DOWN).

Is the video signal (IF) sent 
from pin (8) of tuner 
(TU201)?

Check the tuner (TU201) 
and peripheral circuits.

Is video signal sent from pin 
(17) of IC201 (IF-DEMOD)?

Check FL201 (SAW-FIL), 
IC201 and peripheral 
circuits.

Is the video signal VIN1 
(ATUNER-CVBS) sent to pin 
(191) of IC3002 (VCT)?

Check IC201 (IF-DEMOD), 
CONNECTOR 
(P201/SC2705) and 
peripheral circuits.

Is LVDS video signal (LVDS_0N/0P-3N/3P) sent to pins 
(141)/(140) - (129)/(128) of IC3002 (VCTP), and is CLK signal 
(LVDS_CN/CP) sent to pins (132)/(131)?

Check pins (192)/(170)/(133) of BU3.3V line of IC3002 (VCTP), 
pins (185)/(169)/(142) of 1.8V line and peripheral circuits.

Is LVDS video signal (LVDS_0N/0P-3N/3P) sent to pins (12)/(13) - 
(24)/(25) of CONNECTOR CN1 of LCD-CONT-UNIT, and is CLK 
signal (LVDS_CN/CP) sent to pins (21)/(22)?

Check CONNECTOR (P2305, CN1) and HARNESSWIRE (LV).

Is power (LCD5V) supplied to pins (2) – (5) of CONNECTOR CN1 
in LCD-CONT-UNIT?

Replace LCD-CONT-UNIT.

Is LCD5V supplied to pins (31) – (28) of CONNECTOR (P2305)?
Check Harness Wire (LV).