[ednj]

hey guys,
I have a Dell inspiron 15, running on i7.

I have just turned off turbo boost in the bios. after restarting, the computer gets on but no display on the monitor.
now I cannot even reswitch on the turbo boost in the bios as the monitor is not displaying anything.

any suggestions?

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     ednj,

 

First thing I suggest you do is check that your screen is working ok by running the Dells LCD built in self test, it may be a coincidence that the no display problem happened when you disabled turbo boost in the BIOS.

 

Press and hold the D key on the keyboard while pressing the Power on button, then release both at the same time.

 

Let us know the outcome and we will go from there.

 

NB: Just so that you are aware, your thread was moved here as it is is the appropriate forum for resolving hardware issues while the How-To Guides and Tutorials forum is for "Essential how-to guides and tutorials for everything from computer basics to Windows optimization. Submitted by staff and members." 

[phillpower2]

     ednj,

 

First thing I suggest you do is check that your screen is working ok by running the Dells LCD built in self test, it may be a coincidence that the no display problem happened when you disabled turbo boost in the BIOS.

 

Press and hold the D key on the keyboard while pressing the Power on button, then release both at the same time.

 

Let us know the outcome and we will go from there.

 

NB: Just so that you are aware, your thread was moved here as it is is the appropriate forum for resolving hardware issues while the How-To Guides and Tutorials forum is for "Essential how-to guides and tutorials for everything from computer basics to Windows optimization. Submitted by staff and members." 

[ednj]

Thanks for your reply.
I just performed the monitor test and it's well, there were so many colors on the display.
but on switching on the computer normally, the black display comes back.

NB/ there is a display on the monitor, but it's black.

[phillpower2]

NB/ there is a display on the monitor, but it's black. 

 

 

Not sure what you mean by the above, can you explain for us please.

 

Something that can also cause a black screen is the notebook being toggled to external display mode, there are many variations of the Dell Inspiron 15 and they are not all set up the same, try pressing down the Fn and the F1 to F12 keys down in turn to see if you get your screen back (Fn + F8 is a common combination for Dells).

 

An alternate test if you can, connect the notebook to an external screen to see if you get a display on that, if you do it confirms that your graphics device is working ok.

 

Your screen passing the test is a + at least but if no joy with the above we will need the exact model details to do some research on how to remove the CMOS battery.

 

You are welcome btw 

[ednj]

dell inspiron 5000 series is the model.

this is what I mean with screen being black, and also black when I use external monitor. when I switch it on,and using a bright Torch towards the screen, I can note the display changes to black once I hit the power button. it's totally black, not the blank display as when the computer is shut down.
hitting the power button makes you see the display has changed, but black.
totally insane

[ednj]

display toggle is F8 for this model. I've toggled the display with fn+F8 like 100 times with no luck.
There's no even the Dell logo. but everything else is running,cd ejects, fan runs... 🙃

[phillpower2]

NB/ there is a display on the monitor, but it's black. 

 

 

If you shine your torch into the screen when the computer is powered up can you see any icons or the Windows log in screen in the background, this check best done in a darkened room.

 

display toggle is F8 for this model. I've toggled the display with fn+F8 like 100 times with no luck.
There's no even the Dell logo. but everything else is running,cd ejects, fan runs...

 

If you get no display on the external screen when you press Fn + F8 it suggests one of two things, graphics device failure or in the case of the models of the Dell Inspiron 5000 series models that do not have a dedicated graphics card CPU failure.

 

Is the computer still covered by warranty, if yes, return the computer and have it put right, disabling the CPUs Turbo Boost function is highly unlikely to have caused the issue and is a pure coincidence.

[phillpower2]

Not heard back from you ednj, do you still require assistance or is the issue now resolved, an update would be appreciated.

[ednj]

Many thanks for your reply.

not covered by warranty. I'm thinking to purchase a new motherboard. or what can suggest?

[phillpower2]

Warranty info acknowledged 

 

Does your notebook have a service hatch like the one that I have outlined in the attachment below.

 

 

If you shine your torch into the screen when the computer is powered up can you see any icons or the Windows log in screen in the background, this check best done in a darkened room.

 

 

Did you do the above check.

 

If all else fails I would suggest that you have a local tech store take a look at the notebook as at present there is nothing to confirm that it is the MB that is bad, replacement boards are expensive as is the cost of fitting them I`m afraid.

 

You are welcome btw 

[ednj]

yeah Phil,
I did shine a Torch against the screen, it was totally black, no single letter.

You are scaring me men, $150 cannot buy and fix a new MB?

[ednj]

I got angry and unscrewed the back cover to check the happenings inside or if something is loose.
so thatway, I do not think it's fit for warranty

[phillpower2]

yeah Phil, 

 

 

 

If I am understanding correctly your computer does have a service hatch, with the computer disconnected from the AC adapter do the following if you will;

 

Remove the main battery.

Press the power on button for 30 seconds.

Remove the service hatch.

Ground yourself by touching something like a radiator.

Press the power on button for around 30 seconds.

Remove the RAM and disconnect the CMOS battery (shown in attachment below).

Press the power on button again then leave the computer for 5 minutes or so.

Replace the CMOS battery only.

Attach the AC adaptor only.

Power up the notebook to see if the behaviour changes, any error beeps etc then get back to us please.

 

NB: Removing the back does not automatically void your warranty, you are normally allowed to upgrade your RAM and unless any warranty seals have been broken or damage to the notebook occurred then any warranty should still be honoured, I am not suggesting any dishonesty here but if the notebook is otherwise in good order and there is a current warranty in place you only need to take it in and explain the black screen problem, nothing more than that.

[phillpower2]

Not heard back from you ednj, do you still require assistance or is the issue now resolved, an update would be appreciated.