Hi I have an ageing Mac Pro A1289 (5.1). When stripped down to the motherboard and (bare) processor card the diagnostics are fine. When the (dual) processor card is populated with a single processor, the front panel light flashes and the machine fails. How do I find the cause of the issue?



If this is due to a matched pair of processors not being fitted, how does the system know this on the basis of only one processor?

Hi:

I'm not sure what is causing the machine to fail however; there is a man named Louis Rossman that repairs Mac computers.
Maybe give him a call and ask. He's in New York. The name of the company is Rossmann Repair Group 1-347-552-2258.

https://store.rossmanngroup.com/index.php/about

No it will boot with a single processor you will just have the fans go at full speed constantly. The single processor needs to be in the first cpu slot for the board tray you put in. Also Mac Pros are locked to certain processors going into them by the firmware onboard the machine. Are you using the X series processors of the 1366 series those are required for upgrading the tray to faster speeds. I have done a couple of upgrades and sold off the resulting dual trays putting singles back into the machine to sell it. Another thing to check is making sure you have not managed to bend the pins on the cpu tray processor socket and of course do you know if the chip is good one. It will not be the first time someone tries to use dead processor.

Edit: Oh and Mac Rumors is probably a better spot for the question to be asked in. There are many there who know far more than I do.

https://forums.macrumors.com/

1 members found this post helpful.

HappyTux your interest is much appreciated, - forgive me if I press you on the issue but your input has been by far the most useful I've received so far and may yet get me home!

I'm still unclear which processors will and will not be compatible with the machine. The object of the exercise is not to upgrade anything, - its simply to return it to its original condition before it was "plundered" for spare parts by people who didn't appreciate its qualities (pearls before swine!).

Accordingly I've looked up the model no online (2.66_12CX according to the label on the back) and found this spec
https://everymac.com/systems/apple/m...ere-specs.html

My reading of this indicates it needs 2 x 6 core X5650 2.66 Ghz processors which may account for its not being happy with the 2.66Ghz 5640s and 2.4Ghz 5620s I've tried so far.

From youir expereince is this consistent, and do I need to get a pair of 2.66 Ghz X5650s to be compatible, - or is it something else?

Again much obliged for your help.

M

Going into a dual core machine you may as well go with the X5680 3.33ghz chips they are just under the 3.46 for the fastest chip you can put in at half the costs. The chips you want the 50s will work as well, you were trying a single machine cpu in a dual machine they are missing the interconnect between the processors. With the proper processors in that thing it will fly almost like a new mac pro they sell. It will run the current operating system Mojave if you put in a pc compatible card before starting up its installer. You got hell of a machine there I got a dual machine 5,1 arriving tomorrow. The cpus for the upgrade at the same time I am doing the tray in that and selling it off with the 48 gb of ram it has, then I have spare tray running in my 5,1 that I am putting in that machine body with a 3.33 that goes for sale to, that will have I think 24gb of ram or 16 (4x4) if I get greedy and keep the 8gb sticks for me.