Mini 1.82 Core Duo 2 powers on for 3 seconds then turns off

[MrMacintoshBlog]

Hey Guys!!!!

I have searched for a bit on this forum but could not really come up with a problem just like mine.

My first mini has a problem. It will power on with the light and then promptly turn off in about 3 seconds. The hard drive spins up but the fan does not turn on. No image on the screen or anything. the mini is open for diagnosis and will do the same thing if the cpu is not installed.

Interesting question what will a mini do when it is powered on but doesnt have its cpu installed?

 

[mooblie]

....the mini is open for diagnosis and will do the same thing if the cpu is not installed.

You answered your own question there! I don't suppose you have another CPU to try?

 

[MacModMachine]

a computer needs a cpu to process beep codes , rip out the ram , does it beep ?

have you reset the smc?

try reseating the memory and cpu , also make sure the fan is spinning freely without any bearing vibrations when you spin it with you finger. (if the fan does not work the mac will power itself off to prevent damage)

 

[Hellhammer]

Sounds like a PSU or other hardware problem. Take a look at my guide here

 

[MrMacintoshBlog]

Hey Guys, thanks for the replies so far!!!

I reset the smu, tried reseting both the cpu and ram. The fan also spins freely, but does not come on when the mini is started at least for the 3 seconds its on.

Also no beeps.

 

[MrMacintoshBlog]

also make sure the fan is spinning freely without any bearing vibrations when you spin it with you finger. (if the fan does not work the mac will power itself off to prevent damage)

Great point. Now the question is when you first power on the unit does the fan come on to test and make sure its working properly? If it does turn on the moment the unit is turned on this may be my problem!

 

[spcopsmac21]

Yea your CPU is fried.
Time to call APPLECARE!!

 

[MrMacintoshBlog]

Luckily I found one for $10 shipped coming this week so we will see. Still would like to know more about this fan thing.

 

[MrMacintoshBlog]

Well its not the cpu

Will a bad hard drive cause the machine not to boot?
How about a bad fan or a bad interconnect board ?

 

[hAkron]

When the logic board went on my MBP it did the exact same thing you are describing.

 

[senseless]

Fans usually run on 12vdc and can even be tested with a 9V battery. I'm not sure how long it would take for an overheating condition to shut off the power supply. Seems to me it would take longer than 3 seconds.

 

[MrMacintoshBlog]

thanks for the info guys, I am thinking this is logic board. Which really sucks because that pretty much means the thing is junk. except for parts as the board would be more than the thing is worth..

Ill be able to check the power supply this week. Ill also give the fan a try with a 9v thats a great idea!