How to fix a Galaxy J7 that occasionally gets black screen issue [troubleshooting guide]

Samsung’s #GalaxyJ7 has a top-of-line display but it’s just as easily susceptible to common screen issues as any other smartphone out there. Today’s troubleshooting episode covers a common problem — black screen issue — and how to fix it. We hope you’ll find this one helpful.

Problem #1: Galaxy J7 battery drains quickly, won’t charge to 100%

It goes into a bootloop and drops battery quick. Like I can be at 50% and it drop to zero when I take the battery out and put it back in to stop the bootloop. At times it’ll only charge to like 25% and I’ll remove the battery and put it back in then it’ll read as 93% however the battery never lasts as long as it’s supposed to. Making it unpredictable if I go uptown for awhile and plan on using my phone when done to get a ride home. I used to use it all day, then plug it in at night to charge and unplug it when I woke up in the middle of the night if it was all the way charged or mostly charged. It never used to have problems like this, it only started happening within the last year. I wanna say a few months ago, as this would drive me batty for a year. I’ve done the soft reset, I’ve done a hard reset, and I’ve rebooted the system; I however was unable to locate the cache in safe mode. but I always clear the phone cache nothing helps, or stops it from re-occurring. Phone having issues. — 

Solution: Hi moonsilver445. If nothing changed after doing a factory reset, then the problem must be beyond your level to fix. The symptoms you mention can signs of either a bad battery issue or a motherboard problem. Get a new original Samsung battery, install it, and see how your phone works. If the issue persists even with a known working battery, then you need to send the phone in for repair. There may be an issue with its power management system, or with the motherboard in general.

If the phone is under a year-old, contact Samsung for an in-warranty repair.

Problem #2: How to fix a Galaxy J7 that occasionally gets black screen issue

I bought a Samsung J7 max 20 days back and on the second day of purchase, my phone suddenly got blank (nothing was seen in the display ). But when i called to my mobile using another mobile it rang and also whatsapp messages got delivered but there was no ringing sound or nothing in the display it looked like it was switched off but it was not. Then i pressed the lock button and volume key button which restarted my phone. The charge was also good. This problem happened thrice in 20 days. Could you please tell me what the problem is and how to solve it. — Varshii

Solution: Hi Varshii. If the screen only turns black at random times and not constantly, it may be caused by a software bug. To fix it, follow our suggestions below.

Clear the cache partition

This should be the first thing that you want to do. Clearing the cache partition will force the phone to delete the system cache so it can create a new one. Sometimes, the system cache gets corrupted and when it happens, bugs may develop. To ensure that the black screen issue is not caused by a bad system cache, here are the steps to clear the current one:

  1. Turn off the device.
  2. Press and hold the Volume Up key and the Home key, then press and hold the Power key.
  3. When the device logo screen displays, release only the Power key
  4. When the Android logo displays, release all keys (‘Installing system update’ will show for about 30 – 60 seconds before showing the Android system recovery menu options).
  5. Press the Volume down key several times key to highlight ‘wipe cache partition.’
  6. Press the Power key to select.
  7. Press the Volume down key to highlight ‘yes’ and press the Power key to select.
  8. When the wipe cache partition is complete, ‘Reboot system now’ is highlighted.
  9. Press the Power key to restart the device.

Your phone will create the system cache over time so you don’t have to worry about anything afterwards. Depending on how often the screen turns black, you may have to wait for hours or days to see if clearing the cache partition has been successful.

Boot to safe mode

Should nothing come out positive cache partition wipe, the next thing to do is to check whether or not the issue is being caused by a bad third party app. To do that, you want to run your phone on safe mode. For how long depends on how often, you think, the issue occurs. Again, since the issue occurs randomly, you may have to wait for a few hours or days. This is going to be a demanding troubleshooting step but it’s the only way to know if a bad app is behind the trouble.

Safe mode blocks third party apps so if the problem won’t occur, you know you have an app issue.

To boot your S8 to safe mode:

  1. Turn the device off.
  2. Press and hold the Power key past the model name screen.
  3. When “SAMSUNG” appears on the screen, release the Power key.
  4. Immediately after releasing the Power key, press and hold the Volume down key.
  5. Continue to hold the Volume down key until the device finishes restarting.
  6. Safe mode will display in the bottom left corner of the screen.
  7. Release the Volume down key when you see Safe Mode.
  8. Let your S7 run in this mode for several hours and check for the problem.

Safe mode blocks third party apps and services. If your device boots up fine on Safe Mode but the problem returns on normal mode, you know that one of your apps is behind the trouble. To know which app is causing a problem, follow these steps:

  1. Boot to safe mode.
  2. Check for the problem.
  3. Once you’ve confirmed that a third party app is to blame, you can start uninstalling apps individually. We suggest that you begin with the most recent ones you added.
  4. After you uninstall an app, restart the phone to normal mode and check for the problem.
  5. If your S7 still refuses to power back on, repeat steps 1-4.

Factory reset

Finally, if both suggestions fail to reach a resolution, wipe the phone by doing a factory reset. Factory reset will delete all your data such as photos, videos, documents, etc. so be sure to back them up ahead of time. Once you’re ready, follow the steps below to factory reset your device:

  1. Make a backup of your personal data.
  2. Turn off the device.
  3. Press and hold the Volume Up key and the Bixby key, then press and hold the Power key.
  4. When the green Android logo displays, release all keys (‘Installing system update’ will show for about 30 – 60 seconds before showing the Android system recovery menu options).
  5. Press the Volume down key several times to highlight ‘wipe data / factory reset’.
  6. Press Power button to select.
  7. Press the Volume down key until ‘Yes — delete all user data’ is highlighted.
  8. Press Power button to select and start the master reset.
  9. When the master reset is complete, ‘Reboot system now’ is highlighted.
  10. Press the Power key to restart the device.

Problem #3: Galaxy J7 randomly fails to power back on

I have had several episodes over the last 4 months with my Galaxy J7.  I charge the phone and then it freezes up and gets very hot. The first time I couldn’t get it to come back on.  I took it to the Verizon store and they basically told me it was toast. I took it home (it had now cooled off) and kept playing with the power button.  It eventually came back on but the battery was completely drained. I recharged it and it seemed ok. Yesterday was the latest episode. It was charging and started to shut down and power back up, but it froze while powering on.  I had to do the power button/volume down reboot several times and it was just not powering up properly. Again it was super hot. I left it overnight (after it cooled) with the blue light glowing in the upper left corner. In the morning I plugged it back in and waiting until it was at 100%.  As it was charging, it all of a sudden started to work properly (i.e., red light came on and the screen was back to normal). It appears to be working at the moment. What can be causing this to happen? — Mcalves

Solution: Hi Mcalves. Your J7 may have a bad battery. Try checking if you can improve the situation by recalibrating the battery and operating system. At times, Android may lose track of battery levels causing untimely shutdown. Follow the steps below to recalibrate the battery:

  1. Drain the battery completely. This means using your device until it powers down by its own and the battery level reads 0%.
  2. Charge the phone until it reaches 100%. Be sure to use original charging equipment for your device and let it charge up completely. Do not unplug your device for at least two more hours and also don’t use it while charging.
  3. After the elapsed time, unplug your device.
  4. Perform a warm restart by holding the Power and Home buttons simultaneously until the startup logo appears.
  5. Use your phone until it completely runs out of power again.
  6. Repeat steps 1-5.

Should recalibration won’t make a difference, do a master reset/ factory reset to see if there’s an issue with the software. Follow the steps above on how to do it.

If factor reset will not change anything, there must be a hardware problem causing it. Send it to Samsung to have it fixed.