The Tool Desk
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First, identify which setting is affecting your S21
| What you notice | Likely setting | Where to change it |
|---|---|---|
| The display turns off after a period of inactivity. | Screen timeout, an idle timer. | Settings > Display > Screen timeout |
| Bedtime-related settings or actions activate at a particular time. | Sleep mode, which can be scheduled or started manually. | Settings > Modes and Routines > Sleep |
| The display behavior changes when battery saving is enabled. | Power saving options may affect display settings. | Settings > Device care > Battery > Power saving |
Keep the screen on longer between uses
To change the inactivity timer, open Settings > Display > Screen timeout, then choose a longer duration from the options shown. AT&T confirms this path for the Galaxy S21: AT&T’s Galaxy S21 screen-timeout instructions.
Samsung Canada documents supported timeout choices from 15 seconds to 10 minutes and says the timeout cannot be disabled completely. That range is documented for its general Galaxy guidance, not guaranteed for every S21 software version or market; the choices displayed on your phone are decisive. Samsung Canada’s Screen timeout guidance.
Turn off scheduled Sleep mode
- Open Settings > Modes and Routines > Sleep.
- On the Sleep mode screen, tap Turn off.
- If Sleep mode activates again, review its schedule and automatic start conditions on that screen, then change or disable the condition that is restarting it.
Samsung’s general Galaxy guidance describes this control and schedule setup; menu presentation can vary with your S21’s software version. Samsung’s Sleep mode instructions.
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Check Power saving if the problem follows battery saving
Open Settings > Device care > Battery > Power saving and review the options enabled on your phone. Verizon’s S21-series guide says configurable power-saving options can include setting screen timeout to 30 seconds and turning off Always On Display. The available options depend on the phone’s configuration and software. Verizon’s Galaxy S21-series Power saving guide.
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If the display still turns off sooner than expected
- Confirm you changed Screen timeout, not only Sleep mode. Turning off Sleep mode does not change the idle timer.
- Check whether Power saving is active and whether its settings are changing display behavior.
- Return to Settings > Display > Screen timeout and verify the selected duration. Choose a longer available option if needed; Samsung does not provide a setting to disable the timeout entirely.
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