Mac Pro 2008 flashing light HELP

[MacSteiner]

Hello,

I shut down my Mac Pro 3.1 in the night. Today I powered it up and it did not boot. Right after powering up, the power light flashes continuously until I hold the power button for 3 seconds and power it down. This is all it does. No video signal at all, hence the display remains in standby and does not come up. All fans working normally, including the one of the video card. The HDDs spin up. The configuration is the default one, including the ATI 2600 video card. I tried:

- checking basic connections -- hdds, raiser cards, reinstalling the video card,
- removing the two additional HDDs,
- removing one of the raiser cards or exchanging,
- changed the mainboard battery with a fresh CR2032,

Nothing.

It's installed with 8x Kingston KTA-MP800K2/4G = 16GB total. There are NO red lights on the raiser cards indicating a malfunction with any of the memory modules (I've had a few bad modules before and they do not cause this issue).

Please advise. I have important information on the machine, and it's a work machine I need to bring back to working condition soon.

 

[MacSteiner]

I resolved the issue.

It turned out a malfunction of a pair of RAM modules. Strange the Mac behaved in such a way instead of turning the raiser card's red lights on and booting, especially considering the fact that these modules were not among the primary ones on the raiser cards.