No Brightness Control

[Washac]

Hi

My Mac Pro has no brightness control via the F1/F2 keys and yes I have the correct settings for function keys in prefs, and the USB cable is plugged in. Also the USB cable has been tried in all other ports, all resets have been tried to no avail.

The ACD has been tested on another machine and works fine in every way, the keyboard has been tested on another machine and is also fine, so the problem lies within the Mac Pro in someway.

This all started after I had to send back my ACD for repair and I had to use another display with my Mac Pro, then on return of my ACD the brightness controls refuse to
work.

The other thing is that the brightness slider in the Display Prefs has disappeared.

 

[interslicer]

most 3rd party monitors have buttons on them which control the settings like brightness, and because of this when you use 3rd party monitors you cant change those settings from inside the OS. i dont use an ACD but im assuming if it was working before that the ACD can change that setting from inside the os, which means you must be stuck on it thinking its connected to a 3rd party monitor.

assuming you have tried restarting, have you tried hitting the "detect displays" button in the display prefs?

if that doesnt work maybe restart with the monitor unplugged and then plug it in and hit detect displays?

 

[Washac]

most 3rd party monitors have buttons on them which control the settings like brightness, and because of this when you use 3rd party monitors you cant change those settings from inside the OS. i dont use an ACD but im assuming if it was working before that the ACD can change that setting from inside the os, which means you must be stuck on it thinking its connected to a 3rd party monitor.

assuming you have tried restarting, have you tried hitting the "detect displays" button in the display prefs?

if that doesnt work maybe restart with the monitor unplugged and then plug it in and hit detect displays?

Hi

Tried the detect display, no luck.

Will try the restart with no monitor plugged in, thanks for the suggestion must be about the only thing I have not tried.

 

[Washac]

most 3rd party monitors have buttons on them which control the settings like brightness, and because of this when you use 3rd party monitors you cant change those settings from inside the OS. i dont use an ACD but im assuming if it was working before that the ACD can change that setting from inside the os, which means you must be stuck on it thinking its connected to a 3rd party monitor.

assuming you have tried restarting, have you tried hitting the "detect displays" button in the display prefs?

if that doesnt work maybe restart with the monitor unplugged and then plug it in and hit detect displays?

Hi

Nope, did not work

 

[interslicer]

is the usb from the monitor plugged into your computer?

 

[Amazing Iceman]

Not to be offensive in any way, but have you tried pressing F1 and F2 keys with and without also pressing the "fn" key?

Also, if this is a two-monitor setup, the Menu Bar must be present in the monitor you want to adjust, so in your case, your ACD has to be the primary desktop.

And check under Display preferences to make sure the Display Profile is the correct one.

And duh! I was forgetting the most important step: RESET THE PRAM and NVRAM:

1) Shut down the computer.
2) Locate the following keys on the keyboard: Command, Option, P, and R. You will need to hold these keys down simultaneously in step 4.
3) Turn on the computer.
4) Press and hold the Command-Option-P-R keys. You must press this key combination before the gray screen appears.
5) Hold the keys down until the computer restarts and you hear the startup sound for the second time.
6) Release the keys.

 

[WardC]

Make sure the USB cable from the monitor is plugged into the Mac Pro. The USB cable must be plugged in for it to work (20"/23"/30")

 

[Washac]

is the usb from the monitor plugged into your computer?

Hi

I did say that it was in the OP..........

 

[Washac]

Make sure the USB cable from the monitor is plugged into the Mac Pro. The USB cable must be plugged in for it to work (20"/23"/30")

Hi

Did you read the OP ?

 

[Washac]

Not to be offensive in any way, but have you tried pressing F1 and F2 keys with and without also pressing the "fn" key?

Also, if this is a two-monitor setup, the Menu Bar must be present in the monitor you want to adjust, so in your case, your ACD has to be the primary desktop.

And check under Display preferences to make sure the Display Profile is the correct one.

And duh! I was forgetting the most important step: RESET THE PRAM and NVRAM:

1) Shut down the computer.
2) Locate the following keys on the keyboard: Command, Option, P, and R. You will need to hold these keys down simultaneously in step 4.
3) Turn on the computer.
4) Press and hold the Command-Option-P-R keys. You must press this key combination before the gray screen appears.
5) Hold the keys down until the computer restarts and you hear the startup sound for the second time.
6) Release the keys.

Hi

Function keys are set correctly.

Nope, nothing worked, only thing I have noticed is that at the top of the Prefs/Displays window it states iMac.