Other New monitor issues - connecting Mac Pro 5,1 with DP cable.

[kristeva]

Hi Guys

I hope everyone is well, may I once again ask you brilliant people for some advice please?

My pimped up old Mac Pro 5,1 is still doing sterling service but I recently acquired a Mac mini M1 for music and general office admin. With this in mind I also purchased a BenQ PD2705Q monitor with built in KVM so I could run the 2 computers from the same screen.

My Mac Pro has a NVIDIA GeForce GT 120 512mb graphics card so I was hoping to connect to the BenQ via a mini DP to DP cable.

On first boot up it initially didn't detect the signal, I turned the monitor on and off and it found the signal ok. All well and good until I decided to investigate the screen resolution in system preferences. I clicked the scaled button and saw there was a resolution higher than native (1920 x 1200), yeah I know I was stupid but curiosity got the better of me! I clicked it and the screen went blank!

I rebooted the Mac and no signal detected, I tried booting in Safe mode but still got a blank screen so I installed my old screen and went into system preferences and made sure display was set to native resolution. I then reconnected the BenQ and booted up again and the signal returned on load up but annoyingly went blank again just before I got to the login page.

Annoyingly I couldn't access the BenQ monitor on board controls so I connected up my Mac mini to the BenQ which then allowed me to change the monitor display settings from 1:4 to 1:1 (Native), but again the Mac Pro lost signal on boot up just before the login page.

Any ideas as to whats happened here?

Is it somehow reverting to a higher resolution just before login? Or is the DP cable the main issue?

Cheers

 

[joevt]

Enable screen sharing on the MacPro5,1 so that you can control it from the Mac mini if the screen goes black again. Use screen sharing to change the display mode on the MacPro5,1 so that it is no longer black. Then restart the MacPro5,1.

 

[eyoungren]

OP, zap the PRAM on the 5,1.

 

[kristeva]

OP, zap the PRAM on the 5,1.

Thanks, I did this today but unfortunately no luck.

I thought I might try and connect my Mac mini to my old monitor as it has a spare D Sub mini connector. I purchased a Belkin USB C to D Sub convertor but the screen is super low resolution and system preferences wont let me change the resolution, clicking on the higher resoltions has no effect. can anyone recommend a cable that might work? Or HDMI to D sub?

 

[Tratkazir_the_1st]

@kristeva DP versions mismatch?

 

[kristeva]

@kristeva DP versions mismatch?

would it be worth me trying another cable Tratkazir? The one i'm using is an Amazon basics.

 

[Tratkazir_the_1st]

BenQ PD2705Q DisplayPort: ver 1.4.
"Specifications:
Unlike its Mini-DVI and Micro-DVI predecessors, the Mini DisplayPort can drive display devices with resolutions up to 2560×1600 (WQXGA) in its DisplayPort 1.1a implementation, and 4096×2160 (4K) in its DisplayPort 1.2 implementation. With an adapter, the Mini DisplayPort can drive display devices with VGA, DVI, or HDMI interfaces."
I think - this is the case. Try another cable. M.b. you'll have to think about different video card.

 

[genexx]

Hey there! I had a similar issue a few years back. I could only connect to my Mac through Screen Sharing and had to change the resolution there to make the Monitor work again. I thought F, why is there no countdown like in Windows? Do you want to keep the resolution?

I tried everything and searched everywhere, but there was no way to reset the screen resolution I had accidentally set through System Preferences. I don’t recall if I tried a different display, but that would only be needed to set Screen Sharing for later, allowing me to change the resolution for the desired display.

One thing I always do now on any of my Macs is set Screen Sharing first.

 

[Nguyen Duc Hieu]

would it be worth me trying another cable Tratkazir? The one i'm using is an Amazon basics.

1. Try setting DP version on BenQ to 1.1
2. Try booting MP in Safemode to see if it could transmit the image to the BenQ. If it does, then reset the Display resolution.
If no hope (no display on the BenQ to access MacOS)
3. Remove the bootdisk, connect it to another Mac, access to it and delete 2 files

What you need to do is delete the following files:

/Library/Preferences/com.apple.windowserver.plist
And remove every file named:

/Library/Preferences/ByHost/com.apple.windowserver.*.plist
You will likely have to sudo as root: sudo rm {filename}

Then plug the bootdisk back to your MacPro, reboot your MacPro with and monitor settings should return to defaults.