Chosen Solution
Mac Pro 2.66 GHz Quad-Core Intel Xeon For the past 4 months my Mac Pro 1,1 quad 2.66 has been crashing. I replaced the ram using the specific fully buffered ram, in a pair etc. Blew out all the dust from fans and power supply with a blower. running smoothly all day and left it running overnight. this morning found it to be dead. when i press the power button not a single light on the logic board comes on, no fans starting up or electronic noise. i tried to reset the SMC and the button above it on the logic board with no result. removed the graphics card and tried again. took out the optical drive to find incredible amounts of dust so once again blew all that out and blew air through the power supply and sent dust all over the room. plugged it back in and no result. With everything that i have read i think it has something to do with the power supply. could it also be the tiny flat battery on teh logic board prehaps short circuting the system? If it is the power supply is there just a fuse blown that i can replace? Also if i put my ear right u against the power supply when its plugged in i can hear a very very faint ticking sound, similar to perhaps the sounds ignition sparks make on a gas stove. I dont want to take it into the shop and pay the $70 odd dollars to just have it diagnosed if it is such a simple asnwer so can anyone please please help me!!!!
To reset the SMC on a Mac Pro: 1 From the Apple menu, choose Shut Down (or if the computer is not responding, hold the power button until it turns off). 2 Unplug all cables from the computer, including the power cord and any display cables. 3 Wait at least 2 minutes. 4 Plug the power cord back in, making sure you are not pressing the power button at the same time. Then reconnect the keyboard and mouse to the computer. 5 Press the power button to start up the computer System Reset Mac Pro has a system reset switch on the logic board that you may use to restart the system while it is powered up. You can use this switch to determine if a computer that won’t consistently boot from a cold start has power supply issues. Follow these steps to reset the system: 1 Start up the computer. 2 With a nylon probe tool, press the system reset switch located in the upper right-hand corner of the logic board. If the computer boots after you press the system reset switch, try shutting off the computer and restarting by pressing the front power button. If the computer restarts when you press the system reset switch but not from a cold start, the power supply may need to be replaced.Let us know if you get any changes, also look at the diagnostic LEDs and tell us what you observe. Mac Pro First Generation Power Supply Unit Replacement Apple Part Number: 661-4677
I had the same problem with my MAC machine and tried the all above troubleshooting but no vain, I replaced the PS but problem was same, finally I though to open the power switch connectivity. Unplug the power switch cable tried to turn the system and plug back the power cable again. Actual problem found in power switch, its dont pull back properly and switch connectivity force the machine to shutdown. you should move switch right left and updown and have light finger touch to turn on the System. Replace it with new one if your power switch hv repeated issues. Thanks Muhammad Shehzad, PK
