MP 1,1-5,1 Mac Pro 2007 weird re/boot problem

[Doctor_Claw]

Hi, I have a weird problem with my machine which is a Mac Pro 2007. Here's the details:
(English is my second language, there may be mistakes)

The machine came stock with the dual 2.66GHz Xeon. Battery pin broken but I have fixed it (welded a wire from the positive to the battery's top and hot glue to keep it in contact with negative

When I plug it in the AC cable, it boots by itself - only cold starts seem to work

If the machine was left unplugged for a long time, it would work, I can hear the chime then white screen and boots to the OS (Lubuntu) - tested the HDD and OS on another PC, works

If I dare to restart the Mac, when it reboots I have the chime sound but then no white screen and if I press the power button it shuts off immediately. Same for sleep and I can't leave it working 24/7

I thought it was a RAM problem so I have changed it to a Micron 64GB PC2-5300F kit, it works flawlessly but same problem persists

I have also changed the PSU, worked perfectly at first boot attempt then same problem if I restart or shut down then turn on again. I thought the PSU was dying and it lacked a "kick" to start like an old starter (Now I have a spare one so I am not so mad about it)

I have also changed my video card, from a ATI X1650 Pro to a RX 580 4GB, works perfectly but same problem if I restart

When I try to remove the AC power and press the button on the top-right corner to reset it changes nothing, battery removed or not

If I leave the Mac unplugged from the AC and plug it back after work it works 4/5 times

I have the PDF about the troubleshooting but it says the motherboard might be the problem and might buy one next week but it comes with 2x Xeon 2.0 (1,1 or 2,1 can,t tell for my 64GB kit)

I have spent quite a few bucks on it and i doesn't work yet, what can I do? I've paid yet 60$ for the Mac, 65$ for the RAM, 160$ for the GPU, 55$ for the PSU, I'm getting tired of this. I use this Mac as a retro-gaming, Dreamcast/Gamecube HD emulation machine mostly and want it as my last PC somehow. 64GB is enough for a lifetime

I'm getting desperate, Macs are not what I am used to, please help

 

[Macschrauber]

When the MP come with dual 2,66 than it is a 1.1

But, when u used 64Gb Ram it must have got a Firmware Update to 2.1

So the new logic board needs a firmware Update as well

You can swap the 2.66 dual xeons, regardless of the firmware, re-pasting them is also a good idea so the swap is no big deal.

Not sure what 64 Gb Ram does in a logic board with 1.1 firmware. Have at least 2 Gb of old Ram to test with.

Have a 1.1 in the house with nasty startup also, shuts off when cold, all leads to the logic board, psu and all interchangable parts swapped. But it is one of my many 1.1 Frankensteins I have so its no pain yet. Have to check again when I have plenty of time...

 

[Doctor_Claw]

No, it is a 2,1 (flashed, 2007 it says under it) and the 64 GB of RAM work and dmidecode says the same (MP21.88Z.007F.B06.0707021348)
I "fixed" the problem by switching the HDD by a SSD and works perfectly yet, had to use my PC to install Ubuntu then swap
Funnily the HDD works in my other PC and boots well
I think it is not the motherboard after all but all signs pointed to it, weird

 

[Macschrauber]

Major difference hdd / ssd is the current of the 12 Volt trail. Spinner HDD draws a decent load to spin up.

If you want to investigate further you can supply the HDD with an external supply and plug the data port to the odd sata ports on the logic board. Those are a little hidden beneath the mini pcie port for the wifi card.

 

[Doctor_Claw]

I remember trying these ports, no results. Maybe because I use Ubuntu or all 4 drives are occupied

 

[Macschrauber]

Wrote about those ports as it is easier to plug cables with data and power splitting in them.

 

[Doctor_Claw]

Sorry for the late reply, I forgot I had an account here
Problem solved, bad HDD causing random booting problems