LG KF600w Service Manual page 120

Checking Flow #1
Start
: Make sure that the trouble is about mechanical thing at first.
Check the touch panel?
YES
Checking the 2.6V touch power ?
YES
Checking the signal X+,Y+,X-,Y-?
YES
Checking the SCL,SDA,IRQ ?
YES
Touch key will work properly
Checking Flow #1
- Re assembly touch panel
NO
Replace charge pump(U501)
NO
Replace touch panel
NO
Replace touch IC (U802)
NO