2007 MBP = logic board issue?

Hey, I've got a bit of a hard case on my hands at the moment.

One of my co-workers informed me that her "MacBook Pro's screen was broken." She is getting a new one very soon anyway, as this is a MacBook 3,1 and she is frustrated with how slow it can be.

It turns on. The screen lights up. It goes to the gray boot screen, Apple logo, spinning tick wheel. But wait - what's all this garbled alternating boxes of pink lines? GPU failure? Oh wait, never mind, it's gone. Just an Apple screen now. Aaaand it's back!

And all that it'll do is sit on the spinning tick wheel with garbled display until suddenly, the spinning stops. Freezes.

I have only seen that once, and it was on a similar MBP with a fried GPU - overheated after being left on next to a window on a bright day...

But see, my co-worker's MBP WILL boot to Target Disk Mode. I can easily get all her data off. I even repaired the directory (as that is usually first thing I do).

It WILL NOT boot to an external drive, USB or FireWire. Same freezing tick wheel and garbling.

No, plugging in an external monitor does not help. It doesn't even display anything - no signal.

I am leaning towards logic board failure, but have read about issues with the HDD causing similar problems (though the display issues kinda rule that out)

I just want to know, for reference, what you think might be causing this problem.

There is a chance I may wind up with the laptop to break down for parts - wouldn't want to sell a bad component!

And...why will it boot to TDM but not a FW or USB drive? I mean, it's convenient, saves me taking out the HDD and my adapter...

Thanks for any insight!

 

Oh that again!

So, logic board. Right? The 8600M is soldered on, and the problem is that it has come partially unsoldered?

I assume the system halts when it detects some kind of disturbance to prevent further damage.

I will inform her that my initial diagnosis of logic board failure was correct, and that her HDD is most likely fine (according to my tests, it is).

Still doesn't explain why TDM is a non-issue. Hell, when the FireWire logo was bouncing around the screen, it literally swept away the pink distortions. I was a bit confused by that.

But hey, I'm not complaining.

And she doesn't care if it's totally dead. She's all set to buy a brand new MBP anyway. Kinda wish I could do the same.

Alright thanks for the replies!