Sharp LC-60LE452U Service Manual page 24

5.4.2 Function Troubleshooting（No Search Channels）
Debug RF
signal machine
NG
1.Repair the U5 voltage (3.3V)
2.Repair the U7 voltage (3.3V)
NG
1.Repair U7 timing circuit
2.Repair U3 timing circuit
Sharp LC-60LE450U/LC-60LE452U Service manual
No Search
Channels
NG
Check RF signal
1.Check the U5 voltage (3.3V)
2.Check the U7 voltage (3.3V)
1.Check U7 I2C
2.Check U3 I2C
1.Check U7 timing signal
2.Check U3 timing signal
1.Check the connection of U7
2.Check the connection of U3
Change U3
OK
OK
OK
NG
OK
OK
OK
24
1.Repair U7 or U3 I2C circuit
2.Check the connection of U7 or U3
3.Change U7 or U3
NG
1. Welding U7
2 .Welding U3