Laptop video question (help plz)

[Encrypted Existence]

Okay so I have an ongoing issue with a Sony VAIO VGN-A170P that was brought to me by a customer with display issues. Make a long story short when I power the thing on the backlit screen displays(I can see the image on the screen), flickers, and then the backlight cuts out.

Here's what I have done so far...
1. tested the backlight on the LCD...works fine
2. tested the inverter with my inverter tester (the one from lcdparts.net)...it failed.
3. ordered a replacement inverter (from laptopteks.com)...the (screen) problem persists. The screen flickers the same way as described above and when I test the replacement inverter it fails as well.
4. replace the video cable...problem persists.

I have tried connecting an LCD from a different laptop but when I plug the video cable from that screen into the VAIO's mobo it doesn't do anything at all. I am assuming the screen is incompatible. Is it possible for this to be a mobo issue? Is it even possible for a mobo video connector to cause a flickering backlight that cuts out? My gut tells me that the "replacement" inverter that I received is bad and that I need to try another one. Any insight will be greatly appreciated. Thanks.

 

[pcrepairtech]

you should check the graphics card. it might have been roasted, like leaving it on your bed or lap which covers the air flow for the GPU.

 

[Martyn]

The only other thing in the circuit is the laptop lid switch which controls the inverter.

 

[Encrypted Existence]

Thanks for the replies.

 

[14049752]

you should check the graphics card. it might have been roasted, like leaving it on your bed or lap which covers the air flow for the GPU.

The gpu has nothing to do with the backlight, in the same way that an inverter has nothing to do with what is displayed on screen.

 

[Encrypted Existence]

Question: are lid switches normally integrated into the motherboard? I have searched on google and looked at the machine briefly and I cannot seem to locate the lid switch. I didn't find much on google regarding this particular model of laptop. Thanks.

 

[RicChapman]

Given that the new inverter failed your test obtaining a repalcement part from lcdparts.net should be easy enough, DOA parts are common place so is certainly the direction to head in.

The last backlight issue I had like this was fixed by replacing the backlight but you seem happy that this isn't the issue.

If the new inverter doesn't fix it then the motherboard could certainly be the problem, perhaps a power distrbution issue? Can you check the voltages?

 

[Adept PC Repair]

Something to think about, is there a misplaced magnet?

Magnets often are used to trigger the backlight to switch off to save power when the lid is shut. I'd take a look around the side of the screen and bezel to see if there is a magnet out of position or perhaps not stuck down.