MP 1,1-5,1 Mac Pro Radeon no hdmi signal after boot.

[Joxaren]

I moved my Mac Pro home. Booted into windows 11 to download a game. Had some problems and restarted to check OC settings. Choose Monterey partition in OC boot picker. TV goes blank and says no hdmi after progress bar is showing. I replaced the rx 6600 with Apple Card. Booted to Mojave and no problem. Booted Mojave with rx 580 and got same problem, but there is signal when using dvi to hdmi adapter. Only it has the purple screen problem I have seen discussed. I have to get the display from work to see if the problem is with the TV sets at home or if widows 11 messed up something.

 

[Matty_TypeR]

Have you tried a different cable?

 

[Joxaren]

I moved my Mac Pro home. Booted into windows 11 to download a game. Had some problems and restarted to check OC settings. Choose Monterey partition in OC boot picker. TV goes blank and says no hdmi after progress bar is showing. I replaced the rx 6600 with Apple Card. Booted to Mojave and no problem. Booted Mojave with rx 580 and got same problem, but there is signal when using dvi to hdmi adapter. Only it has the purple screen problem I have seen discussed. I have to get the display from work to see if the problem is with the TV sets at home or if widows 11 messed up something.

Tried to use second hdmi port on rx 580. And it works in Mojave, but not in Monterey. rx 6600 has only one hdmi and no dvi so... Anyway. There is boot picker screen in hdmi on both cads, but when drivers are loaded (I assume this is when gpu fans stop) the signal is lost.

 

[h9826790]

This may help

 

[Joxaren]

Have you tried a different cable?

yes, I tried a different cable. But the result is the same.

 

[Joxaren]

This may help

Thanks! It did the trick with the rx580. Bit still behaves a bit odd on the 6600. And not like it used to before I installed windows (now why did I do that) I have to pull the hdmi cable on the 6600 and connect it again to get signal. But thank you very much for the tip. (now I just have to unmount the EFI partition which I forgot, and brace myself for another go at installing Hogwarts on the windows drive)