My phone has the sleep off and 10 seconds later it's a black screen

Hi,

Try the following:

Start the phone in safe mode (should be the same for your model) and check if the screen stays on.

If it does then a downloaded app is the cause of the problem. The trick is to find out which one. You need to uninstall each downloaded app, one by one and test the phone after each uninstallation to see if the problem is still there or not.

When the problem is no longer there then the last app that you uninstalled is the culprit.

If the problem still occurs when in safe mode then try a factory restore (or reset) and see if this resolves the problem.

Be aware that a factory restore will erase all your data and downloaded apps and restore the phone to its’ factory default (or last system updated) condition so it is important to backup the phone first before performing the factory restore.

Backup the phone using the phone’s backup feature.

Once the backup has been completed, reset the phone using the phone’s factory restore feature.

Once the factory restore has been completed check if the problem has been resolved.

If it has then restore the phone to its’ previous state using the backup that you made earlier, by using the phone’s restore feature.

Once the phone has been restored, check if the problem is still not there

If it’s not then the reset has resolved the problem.