Acer AL1716 Service Manual page 35

3. Panel Power Circuit
Check CN101 PIN 23-24 should have
response from 0V to 5V When we
switch the power switch from on to off
Replace panel
4. Keypad Board
OSD is unstable or not working
Is Keypad board connecting normally?
Is Button Switch normally?
Is Keypad board normally?
Check main board
OK
OK
OK
OK
Check the PPWR panel power relative circuit, Q706, Q704
In normal operation, when LED =green, R725
NG
Should =5 V,
If PPWR no-response when the power switch
Turn on and turn off, replace the U401-TSUM16AK
NG
NG
NG
34
Connect Keypad Board
Replace Button Switch
Replace Keypad Board