Boots to bright white screen

[Keith Ruhl]

I purchased a A1286 macbook pro 15" from a fellow for $200.00
The problem he described with it, and I can concur, is that it boots to a bright white screen. If I attach an external to it, the external will not work unless I disconnect the ribbon cable off the internal lcd screen first.
What could it be. I tried the internal lcd on another macbook and it worked fine.

 

[Keith Ruhl]

Update

I have managed to boot up the mac with the ribbon cable still attached and using an external monitor.
I tried a screen from another macbook pro and it was white too.

 

[jwksmith]

Bad ribbon cable?

 

[Keith Ruhl]

I tried a known working lcd with cable and the result was the same.

 

[joecool99]

most likely GPU issues - read - it's done for.

 

[Keith Ruhl]

If the gpu was bad then why does the external monitor work

 

[joecool99]

missed it. could be secondary issue on the logic board.
is the LCD connector ok?

if you already tried good tested display, i don't think there is other way then to replace logic board.

 

[Keith Ruhl]

I checked out the connector and it is tight to the motherboard.
How is it possible that the output is fine on a external and not on the macbook.
Is there anybody out there that had the same problem and how to solve it?

 

[GhettoMrBob]

The display sounds like it's receiving power and backlight but no data (video).

It could be the logic board connection that's bad...meaning the gpu is still intact, it's just not able to send video out over that onboard connection.

Worst comes to worst..use it as a desktop?

 

[MacInTO]

Here is some background reading on your issue...

https://forums.macrumors.com/threads/1697394/

https://www.facebook.com/MBPDiscretegraphics

https://discussions.apple.com/thread/4766577?start=45&tstart=0