Samsung Galaxy A21 SC-42A Instruction Manual page 139

Trouble
No operation is • Is the screen locked? Press [Side key] to unlock
performed even screen lock.
when tapping the → P.30, P.109
touch screen.
The touch screen • It may be occurred when large amount of data
reacts slowly when is saved in the terminal or transferring large-size
a screen is tapped. data between the terminal and microSD card.
• Do you attach a protection sheet on the terminal? The
operations may be impeded by the protection sheet.
The docomo • Is the docomo nanoUIM card installed with a
nanoUIM card is correct direction? → P.23
not recognized.
Time is incorrect. • It may be occurred if the terminal keeps turned on
for a long time.
Check if "Automatic date and time" is set to ON,
and turn on the terminal at places where signal is
strong. → P.119
• It may be caused by apps installed to the terminal
Terminal becomes
unstable. after purchase. If problems improve when you
start in Safe mode (a function to activate the
terminal in a mode similar to default), problems
may be improved by uninstalling the app.
- To start Safe mode
Press [Side key] for 2 seconds or more when
power is OFF, and after Galaxy logo appears,
continue to press Volume DOWN key.
When power is ON, press [Side key] for 1
seconds or more → touch and hold "Power off"
→ tap "Safe mode".
* When Safe mode starts, "Safe mode" appears
on the lower left corner of the screen.
* To terminate Safe mode, turn on the terminal
again.
- For using Safe mode, back-up the required data
beforehand.
- Note that apps or widgets you created may be
removed.
- Safe Mode is not normal activation. Usually exit
Safe Mode and then use the terminal.
Check and remedy Trouble
Terminal reacts • Confirm the internal memory usage of the terminal
slowly/Behaviors and obtain memory by ending some activated
become unstable/ programs. → P.117
Some of the program
cannot activate.
Data is not • Turn off and on the power. If it does not solve the
displayed properly/ problem, trying "Factory data reset" (P.119) may
Cannot operate improve the symptoms. Note that the operation
the touch screen erases all data saved on the terminal. Make sure
properly. to back up necessary data beforehand.
App does not work • Are there any apps being disabled? Enable the
properly (cannot disabled apps and try again. → P.117
activate, errors occur
frequently, etc.).
Calling
‡
Trouble
Cannot make a call • Is the docomo nanoUIM card installed to the
even though Call terminal correctly? → P.23
key is tapped. • Is the terminal set to Airplane mode? Set the
Airplane mode off, and retry. → P.101
The ringtone does • Is the "Volume" set to minimum? → P.105
not sound. • Is "Ringtone" set to "Silent"? → P.105
• Is the terminal set to Manner mode (Vibrate,
Mute)? → P.104
• Is the terminal set to "Block numbers"? → P.64
• Is the terminal set to Airplane mode? → P.101
• Is the ring time of Voice mail service or Call
forwarding service to "0 seconds"? → P.65
• Is the Play after of Answering message set to "0
seconds"?
→ P.63
137
Check and remedy
Check and remedy
Appendix