820-3115 only starting without screen attached

[2informaticos]

Recharge original BIOS, as is not BIOS issue.

So machine doesn't even start if external monitor is connected?
Do you also need to unplug LCD to start?

 

[Fizzl92]

Ok i flash original Bios back. Yes, it only starts with both monitors disconnected. If there is any monitor plugged in (internal or external) fan just twitch one time. After the fan twitched i can hear a quiet "brumming" sound from the fan and can feel it vibrating until i unplug battery... Pressing power again results in no reaction (no 2nd fan twitch)

 

[2informaticos]

Machine stays on for long time if no monitors connected?
Test it only with USB mouse and OSX pendrive, to assure stable activity

 

[Fizzl92]

Yes it stays on with everything except monitor connected (+USB mouse and pen drive). It starts, chimes and even talks to me after few seconds if i plug my Mavericks USB drive in (it has the voice over thing enabled...)

 

[Fizzl92]

Is there something else i could try?

 

[2informaticos]

This should be something related with AXG block from CPU.
Try to reflow CPU.
Check first if R7403 is correct.

 

[Fizzl92]

R7430 is correct. I gave CPU a reflow same way i do with 2011 MBP/iMac GPU issues to test if its really a GPU problem but that did not change anything aswell...
So i think its time to give up here...