mac pro does not power on

[Lordedmond]

in my limited computer knowledge when the AC power is applied to the psu/mobo combination you should have a standby led on , to indicate the presence of the 5vdc supply for the KB /mouse to bring the unit out of sleep

as you have proved the psu seems to switch on ( have you tested it with a load resistor ? )

is the PSU the correct one for the mobo , not sure is apple do but Hell do, they change the pin outs on the power header ( blew a mb because of this they had reconfigured the + and - 12 leads )

also the cpu/s and ram must be present to allow the MB to come up to power state

sorry i cannot be of more help but without some known/proven tested parts you will be chasing your tail , always assuming that that you do not have the diagnostic PCI riser card to test out the MB ( but then you would not be scratching your head over this )

 

[horvazs]

the logic board no is: 820-2128-A (661-4449)
the PSU: 614-0383
Anyone who knows whether this combination should be ok? I purchased it as for mac pro early 2008.
I did a little search but haven't find anything useful about the correct pinout for my board.
If the PSU pinout should be different then I cannot get any further without exact specification. Can you help here?

 

[horvazs]

now I just figured it out that there is sg wrong with the PS#2 power cable/connector. If I unplug it I am able to switch the PSU manually and the mac starts giving some noises. Means fans switch on, video card starts to run, leds on the memory risers light on but obviously the connector must be for the cpus as they remain cold.
Probably the cable harness I have is for an earlier version but having a specs would not be too difficult to change the wires in the connector.
Could anyone give me information or would be so kind to measure it out?
thanks in advance!
(The connector location is next to the front panel closer to the wireless antenna.)

 

[milk242]

I was looking at the welovemacs website and noticed the power supply you have doesn't match the early 2008 mac pro psu... Maybe you can email them about the difference between the pin outs or maybe you can email ifixit.

 

[horvazs]

thanks, I have emailed my question to Ifixit but they deal with laptops mainly, let's see.
Anyway meanwhile I would appreciate if any of you could help me and would send me the specs of the PS#2 connector. It is easy to measure it out however I know that some disassembly (front vents) would be needed.
thank you in advance
Zsolt

 

[milk242]

How would one measure the psu connector? If you need a volt meter to do that then sorry I can't be of help.

 

[nanofrog]

thanks, I have emailed my question to Ifixit but they deal with laptops mainly, let's see.
Anyway meanwhile I would appreciate if any of you could help me and would send me the specs of the PS#2 connector. It is easy to measure it out however I know that some disassembly (front vents) would be needed.
thank you in advance
Zsolt

You'd really need a wiring diagram and a voltimeter. All black wiring makes it more difficult.

If you get the correct P/N's for what you're using/actually need, a search might produce a site (you'd have to pay for them) that has them available. Might is the key word however.

 

[horvazs]

that is not much help so far...

 

[nanofrog]

that is not much help so far...

Sorry, but short of finding someone with the correct model who's willing to use a meter and trace it out for you, it's the best thing I can think of ATM.

 

[horvazs]

the money so far was not the priority but now as I am having already one PSU (even if it is not the most suitable one) if there is an other possibility would not want to give out further 500-600 USD. And there is not much missing, a bloody specs for a small connector. If somebody has a voltmeter, it takes probaly 5 min to figure it out.
I should not be the only one who has this issue.
You are all experts in macs I count on that...