iMac Pro 2011 imac gpu upgrade ok but no post when screen attached

[Chubbsdad]

Hi can any of you help me figure this out .
Upgraded my 2011 21.5 imac with a 770m working fine without the screen , logged in using SSH all good , when I come to put the display on it does not post. Does that mean My screen is dead , unit was off ebay so dont no much history .
Iv have tested the screen connector for short but seems to be good , is there away I can test the screen out of the chassi
Cheers and by the way great forum

 

[FlorisVN]

Hi can any of you help me figure this out .
Upgraded my 2011 21.5 imac with a 770m working fine without the screen , logged in using SSH all good , when I come to put the display on it does not post. Does that mean My screen is dead , unit was off ebay so dont no much history .
Iv have tested the screen connector for short but seems to be good , is there away I can test the screen out of the chassi
Cheers and by the way great forum

Did you flashed your card already with nicks custom vbios.. ?

2011 iMac Graphics Card Upgrade

iMac 2009 to 2011 MXM3 graphics card upgrade (Lastest update 10/13/2023 - this is the official documentation page - you found it finally!) This is the single and only documentation post. During the last years we constantly updated this post to reflect the lastet development of vBIOS and OCLP...

forums.macrumors.com

 

[Chubbsdad]

Hi FlorisVN , No have not yet flashed my card with Nicks Custom Bios. Its a Dell alienware 3gb and believe it should work out of the box ,which it does on a via displayport and Screen share but as soon as I connect the screen the computer fails to post. What I dont understand is why connecting the screen display cable will stop it posting. Any help would great, would the screen output stop the unit from posting.

 

[FlorisVN]

Hi FlorisVN , No have not yet flashed my card with Nicks Custom Bios. Its a Dell alienware 3gb and believe it should work out of the box ,which it does on a via displayport and Screen share but as soon as I connect the screen the computer fails to post. What I dont understand is why connecting the screen display cable will stop it posting. Any help would great, would the screen output stop the unit from posting.

it works indeed OOB, withouth EFI bootscreen using a compatible Dell/Alienware vbios.
to get best results first flash to nicks custom vbios, and test again !

with stock dell/alienware proper compatible vbios verision, internal imac display aswell as 1 displayport output works..

 

[Chubbsdad]

Thanks for the fast responce , I have a different screen comming soon and will test with that. If no go I also have a K 2000m unflashed so I will flash that with Nicks V bios and change out the card . Hopefully that should work . Ivbeen following this thread for a while and people are doing great things, credit to all involved . The dell card I have does seem to have the correct Bios as in the thread but one thing I notice is the resolution it says something like "extrawide 1398x 780 x60hz " I cant give you a screen capture as I not at home . But my monitor is 1080px786 ,so Im wondering if the bios hasbeen changed.