Asus AST21 Basic Manual page 92

Symptom
Screen response
is slow when you
tap on the
screen/press the
keys.
A message [SIM
card is not
installed]
appears.
The display is
dark.
Cannot recognize
a microSD card.
Display light
turns off too
quickly.
If you cannot find the solution to your problem in the
above table, refer to the au Customer Support at the
website below.
http://www.au.kddi.com/support/mobile/trouble/repair
90 Appendix
Where to check
• Screen response may be slowed
down when a large amount of data
is stored in the product or being
transmitted between the product
and a microSD card.
• Is an au Micro IC Card (LTE)
inserted?
• Is [Brightness] set to dark?
• Is the microSD card installed
properly?
• Is the microSD card unmounted?
• If you do not perform any
operation for a certain period of
time, the screen will automatically
turn off to save the battery power
(Sleep mode).
Ref.
page
ー
P.52
P.74
P.56
P.63