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theBigD23

macrumors 6502a
Original poster
Sep 13, 2008
608
115
I'm not sure what to do. I have a 5K iMac and a non-Thunderbolt display connected. However, the secondary display, I cannot control the brightness. In System Preferences > Displays, there isn't a slider for brightness for the secondary display.

I've tried Control/Option/Command/FN + F1/F2 and it won't do it.

Any ideas?

Display.png
 

Yahooligan

macrumors 6502a
Aug 7, 2011
965
113
Illinois
You have to have the USB cable from the Cinema Display plugged into the computer as well, there's no brightness control when you only have the miniDP cable connected.
 

theBigD23

macrumors 6502a
Original poster
Sep 13, 2008
608
115
You have to have the USB cable from the Cinema Display plugged into the computer as well, there's no brightness control when you only have the miniDP cable connected.
Thanks, but I did have the USB plugged in and tried a different port. Same result.
 

theBigD23

macrumors 6502a
Original poster
Sep 13, 2008
608
115

DeltaMac

macrumors G4
Jul 30, 2003
11,400
3,304
Delaware
hmm... (?)
Tried the download link for that EDID reset tool, and the link worked immediately.
It loaded a blank web page, but also downloaded the app.
Try the link again...
Check your downloads folder.
 

Danielsc2010

macrumors newbie
Jun 27, 2018
16
1
hmm... (?)
Tried the download link for that EDID reset tool, and the link worked immediately.
It loaded a blank web page, but also downloaded the app.
Check your downloads folder.
It would never run anything after the download. Where do I got afterwards?
 

DeltaMac

macrumors G4
Jul 30, 2003
11,400
3,304
Delaware
So, you did, or did not get the download?
You have to open the download (which should be in your Downloads folder), which will mount a folder on your desktop. It has the tool, and a pdf with the steps for using the app.
If you get a message "Unidentified developer" (which doesn't make sense, it's from Apple :D ), simply right click, and choose "Open" from the dropdown menu. It will still tell you the developer is unidentified, but you will be allowed to open the app then. Your Cinema display has to be connected when you run the app, but it will tell you if it is not connected at the moment. (I'm looking at the app now...)
 

Danielsc2010

macrumors newbie
Jun 27, 2018
16
1
So, you did, or did not get the download?
You have to open the download (which should be in your Downloads folder), which will mount a folder on your desktop. It has the tool, and a pdf with the steps for using the app.
If you get a message "Unidentified developer" (which doesn't make sense, it's from Apple :D ), simply right click, and choose "Open" from the dropdown menu. It will still tell you the developer is unidentified, but you will be allowed to open the app then. Your Cinema display has to be connected when you run the app, but it will tell you if it is not connected at the moment. (I'm looking at the app now...)
I have the monitor connected to my MacBook Pro but the link once it goes into the downloads folder, I click it and it does nothing. I have turned off Antivrus but still nothing.
 

Danielsc2010

macrumors newbie
Jun 27, 2018
16
1
I have the monitor connected to my MacBook Pro but the link once it goes into the downloads folder, I click it and it does nothing. I have turned off Antivrus but still nothing.
I am running Catalina on this MacBook Pro if that makes any difference.
 

DeltaMac

macrumors G4
Jul 30, 2003
11,400
3,304
Delaware
So, it is in your download folder. Should be named "EDID_Reset_Tool.dmg"
Double-click to open. There will be a folder EDID Reset Tool that appears on your desktop.
Open that folder. There's your app
Are you getting the "can't open, its from an unidentified developer" message? It's simple to work around that message.
The app won't open the first time with a double-click, so right-click, and choose Open from the dropdown. That will let you open it.
(I just tested it in Big Sur, so should work just fine for you on Catalina.) Look around carefully to make sure that opening the app puts a window or error message underneath another window - which is possible on a messy desktop (like mine!). Note that the open app window is quite small - only about 1-inch x 3-inch
 

Danielsc2010

macrumors newbie
Jun 27, 2018
16
1
So, it is in your download folder. Should be named "EDID_Reset_Tool.dmg"
Double-click to open. There will be a folder EDID Reset Tool that appears on your desktop.
Open that folder. There's your app
Are you getting the "can't open, its from an unidentified developer" message? It's simple to work around that message.
The app won't open the first time with a double-click, so right-click, and choose Open from the dropdown. That will let you open it.
(I just tested it in Big Sur, so should work just fine for you on Catalina.) Look around carefully to make sure that opening the app puts a window or error message underneath another window - which is possible on a messy desktop (like mine!). Note that the open app window is quite small - only about 1-inch x 3-inch
On hold with Apple now, maybe because I am running Catalina, it just won't open. Thanks for your time.
 

DeltaMac

macrumors G4
Jul 30, 2003
11,400
3,304
Delaware
Do you mean that the app (the reset tool) won't open?
Or, that you can't get the .dmg file to open (and mount the folder for the app and the pdf file)
 

Danielsc2010

macrumors newbie
Jun 27, 2018
16
1
Do you mean that the app (the reset tool) won't open?
Or, that you can't get the .dmg file to open (and mount the folder for the app and the pdf file)
The download once I click on it it does something but then nothing. I don't see it under application's, desktop or anywhere.
 

DeltaMac

macrumors G4
Jul 30, 2003
11,400
3,304
Delaware
I just tried with Catalina. Won't open, just crashes...
Works in Mojave, and also in BigSur. Won't stay open in Catalina.
(I have several different system versions that I can just plug in a drive, and reboot. Might be worth doing, just for a one-time reset of your display... :cool: )
 

Danielsc2010

macrumors newbie
Jun 27, 2018
16
1
I just tried with Catalina. Won't open, just crashes...
Works in Mojave, and also in BigSur. Won't stay open in Catalina.
(I have several different system versions that I can just plug in a drive, and reboot. Might be worth doing, just for a one-time reset of your display... :cool: )
Thanks for everything. After all this, I am having the same problem again, I will replace the Power Supply now and put old Logic Board in. Monitor will flash and not come on and I have to unplug and keep plugging in again to keep light monitor on.
 

Danielsc2010

macrumors newbie
Jun 27, 2018
16
1
Guys, I have a A1316 27" Cinema Display that sometimes comes on with no problems and other times, you have to unplug the cord and plug it back in to get it to power up. I have replaced the Logic board and that didn't fix it, then I replaced the power supply and that was not it. If you keep the laptop connected to the monitor and reboot it will be ok. It's only when you unplug the cables from laptop then plug them back in is when you have to do the ritual of unplugging the monitor and plugging it back in. Any ideas of what the gremlin could be? I am getting very frustrated. PLESE HELP.
 

MACtavish

macrumors newbie
Jan 11, 2021
3
0
I too had this issue and found it to be a dodgy profile.
Open colour sync utility, select your monitor from the list then change profile. In my Mac, there were 3 Cinema Display profile so I selected an alternative and presto, brightens control came back instantly.
running 27 inch iMac with 27 inch Thunderbolt Display and 24 inch Cinema Display. working a treat now but, it did take a while to figure out.
What Apple call profiles are in truth, cleverly disguised display drivers.

tadaaa!!!

have fun boys and girls!
 
Last edited:

MACtavish

macrumors newbie
Jan 11, 2021
3
0
Guys, I have a A1316 27" Cinema Display that sometimes comes on with no problems and other times, you have to unplug the cord and plug it back in to get it to power up. I have replaced the Logic board and that didn't fix it, then I replaced the power supply and that was not it. If you keep the laptop connected to the monitor and reboot it will be ok. It's only when you unplug the cables from laptop then plug them back in is when you have to do the ritual of unplugging the monitor and plugging it back in. Any ideas of what the gremlin could be? I am getting very frustrated. PLESE HELP.
I know you're going to hate this reply but It is your monitor profile. open ColorSync utility, select a new profile for that screen type, load it and finally, reset your PRAM.
option-command-P-R on bootup. hold down when you hear the chimes.
 

Danielsc2010

macrumors newbie
Jun 27, 2018
16
1
Scowering all the threads and posts, what was the final consensus for an A1316 27 Cinema Display where I have to unplug the monitor and plug it back in from the outlet to fire it up then when the display does not come on automatically from a cold start and then the display is not that bright when it does come on. I have replaced the power supply and the Logic board and that was not it. The pig tail cables are in new like condition and do not look bad. The only thing left is the LCD, any thoughts?
 

MACtavish

macrumors newbie
Jan 11, 2021
3
0
Scowering all the threads and posts, what was the final consensus for an A1316 27 Cinema Display where I have to unplug the monitor and plug it back in from the outlet to fire it up then when the display does not come on automatically from a cold start and then the display is not that bright when it does come on. I have replaced the power supply and the Logic board and that was not it. The pig tail cables are in new like condition and do not look bad. The only thing left is the LCD, any thoughts?
go t colour sync and select an alternative profile ( display driver ). usually there are several listed for a particular series of screens. it usually fixes it
 

Danielsc2010

macrumors newbie
Jun 27, 2018
16
1
go t colour sync and select an alternative profile ( display driver ). usually there are several listed for a particular series of screens. it usually fixes it
Thanks, but that did not do it for me. How will that prevent the screen from even turning on till you unplug it and then plugging it back in.
 
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