Philips HTS5520 Service Manual page 33

Touch keys do not work
Touch keys do not
work
Go
Check voltage +3.3V on Touch Board(U603
PIN27) and Font Board(XS601 PIN3)
Yes
Check Front Control Board and Touch
Board signals SCL(TOUCH BD U603
PIN19),SDA(U603 PIN18)
Yes
Replace Touch Board
5-2
No
Fix the connection XS601 on Front
Control Board and XP9 on Main
Board
No
Replace U22 on Main Board, or
replace Main Board
Trouble shooting Chart