Chosen Solution
Hello, My iMac is currently stuck with a dim screen, and changing the brightness does nothing at all. I have tried resetting the SMC and PRAM, and the issue is very briefly fixed after a PRAM reset, however the screen dims about halfway through the boot cycle. Any idea why it may be doing this, and how I can resume full brightness? Many thanks!
This is according to just how dim the screen is. If it is almost black, your inverter may have failed or is failing. Here’s how to replace it: iMac Intel 20" EMC 2266 Inverter Replacement
I don’t think that it is stuck on the lowest brightness I think that you back lite went out. Is it just kind faint? If so its your back light so this means it will need replaced before you can get the brightness the rest of the way up.
