1 
1 MacPro 3.1 Wont boot, continuous Chime after power up
My MacPro 3.1 (early 2008) won’t boot. When I press the power button fans spin, then chime sounds and after that the chime sound goes over and over again in a loop. Screen shows multiple vertical lines with colors.
First suspect is the GPU, It’s an ATI 5770 flashed for mac card (worked like a charm for years). I also happen to have the old ATI 2600xt card that was working.
Upon trying the old card, system boots and I hear the chime sound but then nothing, no video.
Upon further testing, I booted the machine with no GPU connected, to my surprise It booted successfully (no video of course). How do I know this? because I connected the MacPro to my network and im able to see and also to connect to it via TeamViewer, transfer files and everything.
So my question is, Is this for sure GPU problem? Can both GPUs be bad even when the old one was working when I did the upgrade? Or is it possible the logic board has some issue? (I tested the cards on both x16 slots, same results). Even after booting successfully without video, could the logic board have some issue with the GPU slots or something?
Sadly I don’t have another MacPro to test the video card, only windows machines that don’t accept these cards.
Thanks to anyone who can shed some light
Es esta una buena pregunta?
2.6mil 
It turned out both graphic cards were bad. What I did was to try the old “cook in the oven” trick and after that both cards booted successfully with no issues (I had nothing to loose so I tried it). Even though they worked I ended up buying a new card and It has been working with no issues.
- de Damian Lepori