[doublepost=1531017519][/doublepost]Thanks to several of you out there with advice on an Apple supported graphics card for my Mac Pro 4.1 flashed to 5.1.
In the end I ordered a Sapphire Radeon Pulse RX 580 through Amazon - expected delivery was 7 to 10 days as I’m out in Hawaii. It arrived 4 days later but I only had the mini 6 pin to 6 pin power cable from my old AMD HD 5770 card not the 8 pin to mini 6 pin required. It didn’t come with the card. I ordered one with a ETA of another 10 days but it came in just 3 days! Great I thought....
I swapped the card withe the added new cable booted up in to to 10.13.5 and ran a few tests. All working well. Download ed a full copy of beta 2 using
@dosdude1 downloaded coped it into the Applications folder as I wouldn’t have had a boot screen to use a usb installer. It started well .... 3 minutes ... select the drive to install to... then it says ‘restarting and shutting down applications’ as other than the installer and finder there were none I expected it to just go ahead quickly. 15 minutes later... stuck - no mouse, not even keyboard to force quite. Did a hard restart. Tried again. And again. And again.... then it reports on rebooting to HS 10.13.5 (something like ‘insufficient resources for installer’ (it was on the screen for a second or so) - I then did a force shut down and tried to reboot. I got no boot chime - only black screen.
I assumed I must have a faulty graphics card to took it out and put the previous AMD HD 5770 back in.
It still won’t boot. No boot chime, no boot screen. It’s not the new card or the old one. I fear coincidentally so other hardware had failed. I Have tried everything I can think of, Different monitors different video cables an types, reset PRAM, SCM, inserted new coin battery, put back old RAM that came with it (6Gb) so I could perhaps boot into an older OSX. No difference- still no boot chime or boot screen. The light next to on/off power button lights up, fans start on the front and on the graphics card (currently the 5770). Hdd are spinning as they get warm.
Old Macs usually don’t die or even fade away they just run and older OS. I’ve just had this one sine 2015 so I’m reluctant to give up - that’s why I got a new Sapphire Radeon Pulse RX 580.
I’m sure it was not trying to install Mojave beta that dealt a fatal blow... Any suggestions?? - I’d be grateful