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

ClassicII

macrumors 6502
Original poster
Sep 21, 2009
303
5
Chicago, IL
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?
 

MacModMachine

macrumors 68020
Apr 3, 2009
2,276
153
Canada
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)
 
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ClassicII

macrumors 6502
Original poster
Sep 21, 2009
303
5
Chicago, IL
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.
 
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ClassicII

macrumors 6502
Original poster
Sep 21, 2009
303
5
Chicago, IL
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!
 
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ClassicII

macrumors 6502
Original poster
Sep 21, 2009
303
5
Chicago, IL
Luckily I found one for $10 shipped coming this week so we will see. Still would like to know more about this fan thing.
 
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ClassicII

macrumors 6502
Original poster
Sep 21, 2009
303
5
Chicago, IL
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 ?
 
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hAkron

macrumors newbie
Aug 17, 2009
27
0
When the logic board went on my MBP it did the exact same thing you are describing.
 
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senseless

macrumors 68000
Apr 23, 2008
1,791
194
Pennsylvania, USA
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.
 
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ClassicII

macrumors 6502
Original poster
Sep 21, 2009
303
5
Chicago, IL
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!
 
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