Laptop Inverter problem?

[bianchi]

Hi there,

I have an old Dell Inspiron 6400 laptop. I had been using an external monitor with it, hooked up to the VGA port. A few days ago, the display on the external monitor went dark. You can just about see it, as if the backlight has gone. The monitor is fine, and I've tried another monitor. Same result. This has me confused as I thought it could be the inverter in the laptop, but the laptop's screen is fine.

Any ideas?

 

[reedo_43]

if you can see ant image, more than likely it is the backlight.They are cheap howerver. This one is used but comes with everything.

http/www.ebay.com/itm/Dell-Inspiron-6400-15-4-Laptop-Complete-LCD-Screen-W-Back-Cover-Hinges-RF365-/351088712769?pt=US_Laptop_Screens_LCD_Panels&hash=item51be849c41

 

[bianchi]

Thanks.

But isn't the backlight part of the screen? Like I said, the monitor is working fine when tested with another system.

 

[reedo_43]

Yes it is part of the screen.

 

[reedo_43]

That's why I sent you a link to a screen.

 

[bianchi]

Hmm, the screen on my laptop is working fine though. It's the screen on the external monitor that has the issue. In fact I've tried a couple of different monitors, same fault.

 

[makkem]

Hi
have you tried a different VGA cable ?

 

[bianchi]

Hi Makkem.

No. I shall try that now.

 

[bianchi]

Ok, tried three VGA cables. Same fault.

 

[reedo_43]

Sorry, I thought it was the other way around.

 

[bianchi]

No worries. The problem is fairly common the other way round it seems. Hence the confusion.

 

[makkem]

All I can think is either the VGA output on the graphics card is at fault or the VGA socket is the culprit.
Its strange as to do this the RGB levels ( three separate levels on three separate socket pins) must have dropped to a low level but the horizontal and vertical syncs must still be ok.
I suppose the laptop screen could be fed with a digital signal with the VGA just for an external monitor and as such it could just be a driver problem but I don't hold out much hope.

 

[ib2007]

Inverters are located inside the lcd. If the monitor tests good with another unit then its not the monitor. Inverter is not the issue here. Its your video card / output or drivers.

 

[ib2007]

Inverters are located inside the lcd. If the monitor tests good with another unit then its not the monitor. Inverter is not the issue here. Its your video card output connector or drivers.

 

[bianchi]

I don't think it's a driver issue as it worked fine for ages and then suddenly failed. I'm guessing something wrong with the socket. When I use the Win+P command in W7 I get a 'no external projector detected' message after a few seconds if I've selected 'projector only'. If I select 'duplicate' or 'extend onto this' I just get the dark/dim screen, Ie if I look really closely I can just make out the boxes etc on the screen.

Thanks for all the help. I'll dismantle it shortly and check the socket. I just wanted to rule out the inverter. I didn't know whether the inverter in the laptop powers/sends an 'on signal' to the backlights in both internal and external displays.