Sharp LC-60LE660U Service Manual page 45

Select PC-IN on the input select menu screen for the right input signal.
Is IC3301(CPU) accessed by I2C, with PC connected, to read the VGA_SCL/_SDA data?
Check the DDC-I2C line and its peripheral circuits..
(1)SC501 pin(15)(SCL), pin(12)(SDA)
(2)IC3301 pin(112), pin(113)
YES
Are there the video signal inputs at pin(166)(R), pin(165)(G) ,pin (163)(B) and pin(164) of IC3301(CPU)?
Are there the VSYNC/HSYNC signal inputs at pins(161) and (162) of IC3301?
Check the line between SC501 and IC3301, and their peripheral circuits.
YES
Check the RGB cable and change resolution format(PC side)
No video at UHF/VHF broadcast signal reception
Are there the IF signal at input pins(24/25)(IF_N/P) of IC3301(CPU)?
Check the IF signal line between IC3301 and TU1101,
and their peripheral circuits.
Check the Tuner I2C lines.
(1)TU1101:pin(10)(SCL), pin(11)(SDA)
(2)IC3301:pin(39), pin(40)
YES
No video (4)
PC:No external input video [PC-IN]
Is PC-IN selected on the input select menu screen?
No video (5)
Is the specified TV signal selected on the input select menu screen?
NO
Check the RF cable and Antena condition
NO
NO
No video at digital broadcast signal reception
Are there the IF signal at input pins(24/25)(IF_N/P) of IC3301(CPU)?
Is there IF-AGC signal at input pin(5) of TU1101?
Check the IF signal line between IC3301 and TU1101,
and their peripheral circuits.
Check the IF-AGC line between pin(38) of IC3301 and
pin(5) of TU1101.
Check the Tuner I2C lines.
(1)TU1101:pin(10)(SCL), pin(11)(SDA)
(2)IC3301:pin(39), pin(40)
YES
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LC-60/70LE660U,C6600U
NO