HELP! My 27" iMac screen brightness won't go to 100% after new SSD

[jedhassinger]

I recently replaced my fusion drive with a PCI-express flash drive from OWC on my 2017 27” 5k iMac. The installation went great and I had no issues. Except my screen brightness stops at about 75%-80%. I can see the brightness level indicator changing on screen but it won’t get brighter after about 75%. I have tried reinstalling Catalina and Big Sur, both with fresh installs, but no change. I have removed the screen and double checked the ribbon connections and they are good. I’ve reset the SMC and PRAM. Any help would be appreciated. (BTW, I have tried turning off the auto-adjusting setting as well.) The room the computer is in has direct sunlight in the afternoon and the screen can be very dim. (In case you are wondering why anyone would want their screen at full brightness)

 

[DeltaMac]

You said that you can see the screen brightness changes, but at some point, the brightness indicator on the screen does not change?
If you get the screen to the brightness that you desire - how is this a problem?

 

[jedhassinger]

Sorry just the opposite, the screen does not get 100% bright and stops actually changing brightness the last 25% of the way although the indicator shows it changing. Any help would be appreciated. I have updated the OP to clarify.

 

[DeltaMac]

Sounds like a problem with the display backlight.
I don't think that can be separated from the LCD panel, so the fix, if that is what is needed, would be to replace the LCD panel.

 

[usagora]

Sounds like a problem with the display backlight.
I don't think that can be separated from the LCD panel, so the fix, if that is what is needed, would be to replace the LCD panel.

Yeah, it sounds like the OP might have inadvertently damaged something during the SSD installation process.

OP, see if you can find some info on possibly replacing the backlight inverter board and cable - one or both may have gone bad or been damaged.