一
一
一
一、
、
、
、
一
一
一
一、
、
、
、
Power supply Trouble
Power supply Trouble
Whether CN2 or CN12 is +5V?
Make sure the power board
input voltage is 5V
power on and check the 2th of U4
is 3.3v?
whether R26 is
welded ?
Check L4、L11、
FB3、FB4, whether
they damage?
Make sure whether next
class circuit of L4,L11 is
not ground short-circuit
Change the 5V,12V
power boards
U4 Dry joint or
damage
Find the ground
short-circuit
point or change
main chip U14
Change
damaged
circuit
component
Y
N
Y
N
Y
Y
N
Y
N
Y
N
Whether power board
input 5v voltage ,or
make sure main board
not ground short-circuit
Whether power
board input 5v
voltage ,or make
sure main board
not ground
short-circuit
N
whether U6 work
normally or change
main chip
