Laptop screen or Inverter issue?

[Blue Banana]

Laptop screen does not display, only on external monitor. I have tried various options for extending and duplicating displays, displaying desktop 1 and 2 only etc.

The funny thing is, the laptop screen displays a gray background colour when switching to the external monitor. I am not sure if it's the inverter. Could it be the cable or even the screen itself? The screen does not show any signs of damage and I have inspected the cables and connections. I used a bright light and shone it on the screen in case the backlight is dead, but nothing can be seen. Can I safely assume the inverter is the culprit here?

 

[Kitten Kong]

What's the make and model of the laptop?

 

[Blue Banana]

Dell Inspiron 1720

 

[Kitten Kong]

First things first. Have you swapped the screen over, for a known working one. Even if its smashed?

That will tell you straight away, if your dealing with a backlight / inverter issue.

Usually if the screen is dark, and you shine a torch, if its an inverter issue, then you will see a faint image of whats on the screen.

As the screen goes grey on the external, I would hazard a guess at it being a graphics chip issue on the motherboard.

With it running Vista, do you really want to start messing around with a laptop which is close to 7 years old?. If it isnt the screen, then I would ber it myself.

 

[Blue Banana]

I am unable to swap out the screen for a known working one, screens are very expensive here and I can't keep stock.

Inverter is fairly cheap though, but I never had this sort of repair, only screen replacements, so I am grateful for the guidance. What would you do in this situation?

 

[Kitten Kong]

do you not have an old lcd screen?. Irrespective of the size of screen, if its lcd it 'should' work for testing purposes.

If it still does the same thing, then that tells you, it isnt the actual screen.

As you can not see anything with the light trick, that tells me it isnt the inverter (in most cases). Which leads you to either motherboard or graphics harness.

As a external monitor shows a grey screen, rather than the full image (if it was the full image, i'd say it was the harness). As it isn't, then I'd say a motherboard fault. In which case, it isn't worth stripping it down further for full diagnosis.

Though if your quiet, and you want to get to the bottom of the issue for your own diagnostic purposes, then do so. Obviously you would not be able to charge the client, as this is for your own learning purposes.

Personally, judging by the age of the machine, it running vista. Cost of the motherboard / screen alone in my opinion would outweigh the value of the laptop.

I would contact the client, offer to backup their data, and write the laptop off, as beyond economical repair.

In my eyes, if the cost of the repair, is >50% of the cost of a new machine, it isnt worth while repairing. Especially as laptops are so cheap now a days. It's basically a throw away society now.

 

[kisk]

I know you really want it to be the inverter but if you don't see a faint image with a flashlight then it is most definitely NOT the inverter. The inverter powers the backlights (CCFLs) only. That is its only job.

 

[Romaniac]

If the grey screen is easily visible, and not super faint, it's likely the screen then.

Can you adjust brightness at all?

 

[Markverhyden]

That's from 2007 or so. Given that it's not a back lighting thing I'd be talking to them about placement. Time to move on unless the EU has a compelling reason to want it working such as a special app that is not available anymore.