Dual 30" Apple Cinema Displays | Sync / Power Problems on Boot MP 5.1

[JulianBoolean]

Intermittent Problems:
On Boot ups, sometimes only one monitor will power up. Sometimes neither monitor will power up. Sometimes power to the USB ports will work, sometimes not.

A Good Boot Up Sequence For My System :

0. Push power button on Mac.

1. I will see the power light come on my main / front facing monitor early in the boot process, while both screens are still dark.
If I see this power light come on (it's the small pin light in the bottom right corner of aluminum bezel) Then I know the rest of the sequence is going to work out fine.

2. My right side / pallets monitor screen lights up to a white screen first.

3. The front facing / main working monitor lights up ... with the user login screen showing up a few moments later.



A Bad Boot Up Sequence For My System :

0. Push power button on Mac.

1. The power light indicator on the front facing (main working) never light ups. If I see this, I know the rest of the boot sequence isn't going to work, and I'm headed for a dead end. But here is what happens next...

2. My right side (pallets monitor) screen lights to a white screen. But the login screen never shows up on this monitor.

3. The login screen is probably now sent to the front facing (main working) computer, but I wont see it, because it's completely black (no power)


Also, on rare occasions, this weird thing will happen:
I'll manage to get both monitors powered up, but the power to the USB ports on the back of the displays will go dead, only to return to normal on the next power down and boot up.


Some Context, Background:
I've had this problem for many years. Have never found the cause, and the workaround solution is pretty tedious and probably harmful to my drives and motherboard.


My Horrible Work-Around Solution:
If I see that that I'm not getting power to the main monitor where I login, then I know I'm headed for a dead end. My only choice is to...

1. force quit, hard power down by pressing and holding the power button front of cheese grater.

2. Unhook every cable and every power source connected to the right side pallets display.

3. Wait 3 minutes. Now that I'm making simple for Mr. Mac, with only one display to power up, boot up again and pray for power to get properly sent my main monitor. Keep repeating the hard power down and boot process until Mr. Mac understands to send power to the only display that it is hooked up to. Might get it on the first try, might take 3 attempts.

4. When I finally get a good boot up with power to the main main display, hook up all cable and power to the pallets monitor. This never fails to work once resolve step 3.


Also On Rare Occasions, This Weird Thing Will Happen:
I'll get a good boot-up with both displays, but the USB ports on the back of the main display wont pull any juice. But the USB juice comes back on the next boot up. The USB and FW 400 ports on the pallets monitor stopped being able to power anything a few years ago. But the ports on main monitor come and go sporadically.


Best Guesses:
1. Power issues overall.
2. Power issues related to these aging (2012 and 2015 monitors)
3. Some kind of software / syncing problem.


Hesitation On New Displays:
If the only solution is two new monitors, then I can do that. It's long overdue. But I don't want to spend a few thousand dollars for two new displays, only to have the same issues re-appear.

Any advice, suggestions, or wild guesses would be greatly appreciated

 

[joevt]

I don't connect the FireWire of the display because it's been broken since I got it. USB is sort of required for easy brightness control, and my keyboard.

 

[JulianBoolean]

I don't connect the FireWire of the display because it's been broken since I got it. USB is sort of required for easy brightness control, and my keyboard.

@joevt Thanks for your reply. There's a delicate balance on how to write about a problem. Too much info, nobody wants to read, but some will skim. Not enough info means there may be difficulty with diagnosis.

I don't have anything thats FW 400. That I sometimes lose power to the USB ports on the back of the monitors is the least of my problems, but an interesting diagnostic detail with regards to power flow.

 

[JulianBoolean]

The TLDR version of Issue = Sometimes both monitors will be black on boot up. Sometimes my pallet monitor will boot up (to white screen) but since it is not where my login screen appears, that's a dead end, and leads to a hard power down.

That I cannot boot because of this dual display issue with out a series of hard power downs, un hooking my 2nd display, and then re-attaching after getting main display working normally is my issue. Hard power downs are not great to drives or mother boards.

That power to the USB ports on the back of one display has died, the other comes an goes is a diagnostic detail.

Thanks in advance to the community for any advice.

 

[joevt]

I don't think I've ever had problems like you describe
1) the FireWire problem which causes the OS to hang or something (I don't remember the symptoms - the 30" is from 2005 and I've never used the FireWire since I found it was broken then)
2) The 23" Apple Cinema HD Display from 2008 had a bad power supply and a replacement from ebay was also bad but then I replaced it with the power supply from ebay for a 30" and it's been fine ever since.

I think replacing the power supply is the only thing you can do.
Have you tried testing the displays with a different Mac or PC or GPU?

 

[JulianBoolean]

Hi JoeVT,

Great replies, much appreciated.

It's poetic justice that I've finally found the solution to this mystery without fully understanding the cause. Both monitors are booting up and functioning normally now.

However, the USB and FireWire ports on the back of the main display no longer work, the USB and FireWire 400 ports on my pallets monitor stopped working last year.

Now that I'm hooking my USB keyboard and USB Wacom Tablet directly into the cMP, no issues at all. Speaking to your point #1, My best guess is ...now that the faulty USB ports are finally dead and out of the loop, it's no longer causing the OS to hang or get out of sync on booting up.

I'm now free to look at new display purchases, because it likely wasn't an OS or cMP issue.

Thanks again for your assistance.

 

[joevt]

Glad you got it working. I remember with the FireWire issue I could see errors in the console log when I connected the FireWire so I stopped trying to connect it. I'm not going to try it to see if the problem magically went away now that I'm using macOS 10.15 instead of 10.5. I'm glad the USB of the display is still working for my keyboard and mouse but if it wasn't working, an extension cable can be used easily with USB 2.0 devices since they only require 480 Mbps.

 

[joevt]

Also, since you're not using USB anymore, you can't use brightness control in the Displays preferences panel or with the keyboard. Luckily, unlike the LG UltraFine displays, the Apple Cinema displays have brightness control buttons on the side of the display and a power button. I wonder if the Cinema displays support brightness control using DDC/CI? There are apps for that.