2009-2011 27" iMac as an external display

[zoran]

I wonder, why aren’t there any Controller Boards that can provide 100% brightness? Why are there any built, they would sell crazy I recon.
Is it because the companies that build them, they just want to keep a low cost product?

 

[zoran]

is it possible to know which part of the controller board is responsible for the lower display brightness?
Might it be the led driver chip, the power adapter or something else?

Is it possible to connect the display with the controller board and the power adapter, without removing any parts from the iMac? Can i just leave it as is and just connect the controller board, just to see if its working and then make the full installation?

 

[head honcho 123]

Also following this great thread.

I had a iMac Late 2009 gutted to use as an external monitor. Should've kept all the parts as it was working fine, but too late now.

I bought a board on Aliexpress. Came with a 12V 5A PSU. Changed it out to a 12V 10A psu. Regardless of the PSU, my wall power meter says it's pulling 35-37Watts. I think the display is rated 100W from the LG spec sheet, which is what made me get the 10A PSU in the first place

Looks like the board itself can't pull that much power.

Would be awesome to get better brightness... I'm going to try to email the board manufacture to see if if there's any other way.

edit:
part list
PSU https://www.amazon.com/dp/B00MYIY2KK?psc=1&ref=ppx_yo2ov_dt_b_product_details
PSU https://www.amazon.com/dp/B087LY94T6?psc=1&ref=ppx_yo2ov_dt_b_product_details
board: https://www.aliexpress.us/item/3256804968823952.html?

 

[head honcho 123]

I wish this post mentioned which board they used bc it seems like they were able to solve the problem with display brightness:

LM270WQ1-SDA2 as external display

Hi everyone. I have an late 2009 27" iMac that some time ago while I was upgrading the gpu and replacing the dvd with a ssd, I broke something on the logic board so since that I had no display on it, I tried to resolder the lvds connector but no luck. Any way the iMac works great with other...

www.tonymacx86.com

 

[head honcho 123]

I got a reply from the board manufacture.

"Using the original machine's iMAC backlight board can reach the maximum brightness"

doh!!! I threw mine out.

hope this helps someone in the future. don't throw that part out!

 

[zoran]

I came across a very strange way to fix a bad GPU for the 27" iMac. That strange way is baking it in the oven and then applying new thermal paste to it... has anyone heard about this before, does it work?

 

[Leandean]

I got a reply from the board manufacture.

"Using the original machine's iMAC backlight board can reach the maximum brightness"

doh!!! I threw mine out.

hope this helps someone in the future. don't throw that part out!

How would you connect the original backlight board to the controller board?

 

[Nguyen Duc Hieu]

How would you connect the original backlight board to the controller board?

Be careful, you might burn the board in 10 min at 100% brightness setting.
https://forums.macrumors.com/threads/display-brightness-of-my-old-imac.2366331/post-32887295