Moving pixels when moving cursor

[Matt-Sir]

Hi,

I have a Dell Latitude 7480 with a bit of a strange issue. The screen has dead pixels that move when the cursor moves. The original screen is 14", I tested with a 15.6" screen and there are no issues so, I did what I thought was obvious and ordered a replacement 14" screen. Now I'm getting the same fault with one exception, with the original screen the picture would lock up and the laptop would appear to freeze but it was only the picture that was frozen, with the new replacement screen, I still get the moving pixels but the picture doesn't freeze.

I'm confident it's not a software fault because I get the moving pixels on post screen and in the bios. My natural instinct tells me it's probably a GPU fault but I'm doubting that with it working perfectly fine on a bigger screen.

If any body has any suggestions I'd appreciate all the help I can get,

Thanks

 

[photonboy]

How can you go from a 14" screen to a 15.6" screen?

Do you mean an EXTERNAL monitor?

Yes, it's a GPU issue though I'm not sure why an external monitor would work as well.

Did you try an external monitor as the ONLY monitor? (you can switch from within Windows to have the image on laptop only, monitor/HDTV only, both cloned or one as an "extended" monitor.)

Either way, sounds like a hardware issue that is not fixable beyond sending for repair. No warranty?

If that's too expensive then consider using a monitor only.

 

[photonboy]

My guess is there is a problem with the VRAM (video memory).

That should be SHARED from system memory though, so I suggest running MEMTEST86 www.memtest86.com for a full pass

I don't think that can test all the system memory if some is used for video.

*But regardless of the results, it's POSSIBLE that swapping the memory stick (i.e. DDR4?) could fix the issue.

 

[Matt-Sir]

Not external no. I removed the screen and connected the screen ribbon to a 30 pin 15.6" just for the sake of testing a screen. I didn't have any 30 pin 14" screens to hand to test with

How can you go from a 14" screen to a 15.6" screen?

Do you mean an EXTERNAL monitor?

Yes, it's a GPU issue though I'm not sure why an external monitor would work as well.

Did you try an external monitor as the ONLY monitor? (you can switch from within Windows to have the image on laptop only, monitor/HDTV only, both cloned or one as an "extended" monitor.)

Either way, sounds like a hardware issue that is not fixable beyond sending for repair. No warranty?

If that's too expensive then consider using a monitor only.

 

[Matt-Sir]

I'll give it a shot and see, I do have some spare DDR4 I can test with, thanks.

My guess is there is a problem with the VRAM (video memory).

That should be SHARED from system memory though, so I suggest running MEMTEST86 www.memtest86.com for a full pass

I don't think that can test all the system memory if some is used for video.

*But regardless of the results, it's POSSIBLE that swapping the memory stick (i.e. DDR4?) could fix the issue.

 

[photonboy]

Not a system memory issue then since the 15.6" screen apparently worked.

That's very ODD though. Two different 14" screens have the same issue but a 15.6" screen worked?

*you can also try using HDMI, but I bet you'll see no issues on the monitor or HDTV.

Anyway, you need someone who knows more about laptops than I do. Not sure what's DIFFERENT about that 15.6" screen though. Lower resolution? (not sure why that would help though)

 

[Matt-Sir]

Started MemTest early on Tuesday and left it running until Thursday morning. 28 Passes with no fault but it also seems to have cleared up the problem which makes me think it's a north bridge fault

 

[photonboy]

Started MemTest early on Tuesday and left it running until Thursday morning. 28 Passes with no fault but it also seems to have cleared up the problem which makes me think it's a north bridge fault

strange