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Venue 11 Pro 7140 black screen when power on

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Venue 11 Pro 7140 black screen when power on

This question has been answered by Angus Carson

All, 

I have a Venue 11 Pro 7140 8Gb / 256GB and am facing a problem where the machine will not turn the screen on. 

The power ran out when the machine was asleep/idle (click side button, screen off). Now, when I try to turn the machine on I get a vibrate to indicate the machine is powering on, but no screen. If I give the machine 10-15 seconds, I can also press the windows key to get a vibration, indicating that the machine has booted to the windows loging screen - only I cannot see this because the screen is still black. Incidently I also had this happen on my old Venue 7130, but was able to hard reset it. 

So far I have tried:

Holding the power button for 10+ seconds
Holding the power button for 30+ seconds
Holding power and the volume down key (This causes the screen to cycle full screen colours: White Black Red Blue Green. Looks like a test function)
Holding power + up volume (no response)
Holding power + windows key (No response)

Following the direction given in another dell support thread I also unplugged the main battery. I was not confident in unplugging the CMOS battery as the connector disconnect method wasn't too clear and I was worried about causing damage. 

The machine has been on charge for about 5 hours - so should also have a full battery by now. 

Are there any bright suggestions as to what I can do next?

Verified Answer
  • Only days ago I encountered the same issue with my 7140.  The issue was clearly tied to my dying battery keyboard.  I took the same steps you did with no luck!  However, I am happy to say that the unit is now up and running after unhooking main battery, CMOS battery, and all of the ribbon cables under the main battery.  I also removed the SSD.  After everything was removed, I held down the power button for 60 seconds to drain any current in the system and left it from morning to night (approx. 10 hours).  I held the power button for an additional 60 seconds, then replaced everything mentioned above.  The first boot was slow,  but it has been back to normal since then.  I did re-flash the bios with the latest version just in case any UEFI data was corrupted by the issue, which is certainly possible since the issue prevents even the UEFI from properly loading.

    I would advise that, if you are using a battery keyboard, do not use when attempting the above steps.  It was clearly the problem for me, as diagnostic tests run since getting my tablet back up have clearly shown.  Good luck!

  • Wow excellent finally a solution that  does not involve logging a ticket with Dell and having them send an engineer who replaces the M'PCB.  

    Steps I carried out:

    1. Removed little side screw and rear cover

    2. Disconnected main battery

    3. Disconnected CMOS batter (fiddly little connector be careful not to break it)

    4. Press and hold Power botton (I did about 60 seconds incase anything needed to discharge)

    5. Reassemble

    6. Power back on and enjoy a working tablet again. 

    Thanks for posting as this had been bugging me for when the support run out if these devices would last.  Seems they might have a chance to live beyond warranty now. 

All Replies
  • Additional info:

    Worked out how to disconnect CMOS battery safely. Left main battery and CMOS battery disconnected for 3 hours. Plugged back in, same response as above.

    Left on charge overnight, now will not respond at all unless I hold the power button for 45 seconds, then I get one vibration, and nothing. 

    If I hold down volume and power then I can still get the screen to do it's test cycle of colours. 

    I cant believe the run I'm having with these machines. First the 7130 did the same thing,and now the 7140 as well. 

    Any bright suggestions?

  • Only days ago I encountered the same issue with my 7140.  The issue was clearly tied to my dying battery keyboard.  I took the same steps you did with no luck!  However, I am happy to say that the unit is now up and running after unhooking main battery, CMOS battery, and all of the ribbon cables under the main battery.  I also removed the SSD.  After everything was removed, I held down the power button for 60 seconds to drain any current in the system and left it from morning to night (approx. 10 hours).  I held the power button for an additional 60 seconds, then replaced everything mentioned above.  The first boot was slow,  but it has been back to normal since then.  I did re-flash the bios with the latest version just in case any UEFI data was corrupted by the issue, which is certainly possible since the issue prevents even the UEFI from properly loading.

    I would advise that, if you are using a battery keyboard, do not use when attempting the above steps.  It was clearly the problem for me, as diagnostic tests run since getting my tablet back up have clearly shown.  Good luck!

  • Wow excellent finally a solution that  does not involve logging a ticket with Dell and having them send an engineer who replaces the M'PCB.  

    Steps I carried out:

    1. Removed little side screw and rear cover

    2. Disconnected main battery

    3. Disconnected CMOS batter (fiddly little connector be careful not to break it)

    4. Press and hold Power botton (I did about 60 seconds incase anything needed to discharge)

    5. Reassemble

    6. Power back on and enjoy a working tablet again. 

    Thanks for posting as this had been bugging me for when the support run out if these devices would last.  Seems they might have a chance to live beyond warranty now. 

  • This is EXACTLY what I have done, and it works.  A few remarks:

    - You don't need to remove the battery: just disconnect it from the motherboard.  My VENUE battery is screwed to the frame: it's the latest VENUE model that comes with the main battery not changeable like the previous VENUE model that has 2 snatches to take out the main battery.

    - You don't need to remove the whole internal frame to remove the CMOS battery: just disconnect the CMOS battery small twin cables from the motherboard.  The connection is not trivial, but if you look carefully, you will see that the disconnection is an horizontal move, not a vertical move as for the main battery. 

    GREAT!  -- Jean.

  • Tried this solution and still just get an amber light for about 3 seconds when I hold down the power button. When I plug the tablet in there is no light indicating that it is charging. It appears that what caused this is my battery was critically low and instead of plugging it in I just closed the lid to the keyboard and let it drain to zero while I slept. Then when I woke I plugged it in and noticed it was not charging, or turning on. I held a multimeter to the battery terminal and there is a voltage so I know it's not the charging port module.