Samsung YP-U5 Service Manual page 19

Troubleshooting
4-1-4 If the button doesn't work
Faulty power button
Does the power button on the
PCB work when pressing it?
Yes
Is the voltage on R14 between
0.9V and 1.0V while the button is
Check that the resistance
is R14=1KΩ and R90=100KΩ.
Is the soldering done correctly?
(Detailed inspection is required.)
4-6
No
1
being pressed?
 Refer to wave pattern
No
image of Fig. 4-2.
Yes
Replace the board
Yes
Repair or replace the knob key and
No
Repair the elements and check it
check it again.
again.
Samsung Electronics