Macbook Pro 13" mid-2009 powers up but won't boot.

[ntrn]

I have previously posted about my mid-2009 MBP which stopped working (no charging, no powering up).
I have replaced the dc-in board and now the power adapter LED lights up and I can start up the computer shorting the power pads (power button doesn't work, probably something related to the keyboard cable?).

When I short the power pads, the fan starts spinning and the front LED turns on, which means power is probably ok, but the screen remains off.
I've tried connecting an external display, but still there's no signal.
I was suspecting display cable, but I'm worried it could be something else since the external display doesn't work too.

Any tips?

Thanks.

 

[The All American]

My computer ,of the same year and model, wouldn't charge or start. I replaced the battery and charger and it has worked flawlessly since.

 

[DeltaMac]

You said in your other thread that you have a new power adapter, is that right? If not, you should try a different power adapter next.
When you see the front LED come on - do you get a Caps Lock light when you press the caps lock key?
Do you get a boot chime?

If you get caps lock light, but no boot chime - try different RAM sticks.
If you get neither, then you need to replace the logic board.

Guessing from your other thread that the power is not sufficient to drive the graphics card, which could mean that the power circuit on the logic board is not working properly - or that the graphics chip has failed.
Either way, the problem will be on the logic board.
The power circuit on the logic board may have been the culprit all along, and caused a part failure on the Magsafe board (the dc-in circuit). So you got that partly working. The power circuit may just pull that down again, hard to say.
If the weakened power circuit took the graphics chip with it, then you may have multiple problems (and you may never get it right with your present logic board.