Mac Pro won't boot...help!

[SadChief]

My Mac Pro Quad Early 2009 won't boot (have a Samsung 470 SSD as bootup disk). Dreaded interdiction sign.
Tried to boot it then from a HDD clone I had - to no evail. Same thing.
In target mode from my MBP, both these disks on the MP are accessible and look OK. I could even boot my MBP from the Samsung SSD in the MP via Firewire 800.
Very queer.
Thank you for any suggestion you might have.

 

[666sheep]

Reset PRAM first. Check if your MP does boot from install DVD.

 

[SadChief]

Reset PRAM first. Check if your MP does boot from install DVD.

Yes and yes (forgot to tell it from the beginning).
I did reset SMC also.
Installed also *normally* Lion (no incident message as of writing files), on a third disk. Final boot lamentably failed, as described (interdiction sign).
Thank you.

 

[Velin]

This is a tricky one. Target mode from a lappy would have been my first suggestion, but you did that. And it boots the install disc too? Strange.

Were the hard drives in different sleds? Because one of the things I would look at is a damaged SATA connection -- though if you can boot on install and get through most of the install, I don't think this is it.

Other thought is a dead PRAM battery? Again, unlikely this is the culprit, but a bad battery can cause some awfully strange problems to arise.

If you have the original RAM you could swap out all the sticks and try that too, just to cross it off the list. Again, very unlikely, as bad RAM usually causes that dreaded blinking red light, and the machine won't even turn on.

If not PRAM or PRAM battery, and not RAM, and not a bad HDD/SSD drive, and not a bad SATA connection, mmm, it becomes more likely there's a mobo or CPU issue, unfortunately -- and the tools needed to properly evaluate those, most home aficionados don't have.

I've never had a CPU fail on a Mac. But I have had CPUs begin to fail on PCs, especially Dells around five years ago, and it can cause all kinds of major problems that will drive one crazy (I'm not saying that's what it is).

 

[minifridge1138]

Try re-seating the RAM.

 

[SadChief]

This is a tricky one. Target mode from a lappy would have been my first suggestion, but you did that. And it boots the install disc too? Strange.

Were the hard drives in different sleds? Because one of the things I would look at is a damaged SATA connection -- though if you can boot on install and get through most of the install, I don't think this is it.

Other thought is a dead PRAM battery? Again, unlikely this is the culprit, but a bad battery can cause some awfully strange problems to arise.

If you have the original RAM you could swap out all the sticks and try that too, just to cross it off the list. Again, very unlikely, as bad RAM usually causes that dreaded blinking red light, and the machine won't even turn on.

If not PRAM or PRAM battery, and not RAM, and not a bad HDD/SSD drive, and not a bad SATA connection, mmm, it becomes more likely there's a mobo or CPU issue, unfortunately -- and the tools needed to properly evaluate those, most home aficionados don't have.

I've never had a CPU fail on a Mac. But I have had CPUs begin to fail on PCs, especially Dells around five years ago, and it can cause all kinds of major problems that will drive one crazy (I'm not saying that's what it is).

Thank you for the very exhaustive point of view from which I learned a lot.
Now I think I should have my machine thoroughly checked on Monday at a Genius Bar.

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Try re-seating the RAM.

Yes, I exchanged the OWC memory sticks with the original Apple sticks and tried again. Same thing.

Thank you.