Intermittent Startup Problem (hardware)

[j3sp]

Hi,
I am a new member of this forum and I joined purely to see if I can find a solution to my startup problem. I first tried searching the net to see if I could find anyone having experienced anything simlar, but without being succesful.

My mac is an iMac flatpanel 17", 1.25Ghz, 512Mb SDRAM, 80Gb Hd. I also have an external LaCie 120Gb firewire drive and a Hp psc All-in-one USB printer. I purchased this computer for my wife's birthday 1.5 year ago and it worked like a charm the first 10 months. Over the summer, when we were on holidays, I shut the computer down and unplugged it from the wall. 3 weeks later when trying to boot the computer, it refused to start. No lights came on, no sound from the computer what so ever. After checking cables and unplugging all perpherials without any change, I assumed the internal power pack to be fried and I engaged the warranty and sent it to Apple for fixing. They changed the power pack and everything seemed to be working normally again. I had bad feelings about this though so I decided to purchase the extended Apple Care plan (another 2 years of warranty). 3 months later I had the same problem and the computer was sent to Apple again but the computer decided to start just fine as soon as it arrived at Apple. They kept it for a week trying to repeat the problem but in the end the computer was just sent back without any changes. Another 3 months passed and then I was facing the same problem again. The computer was stone dead and nothing was working. I unplugged everything and just let it rest for a few days... then it started again without problems. The problem occurs only when it has been shut down completely and only sometimes. Restarting (selecting 'restart' from the menu instead of 'shut down') isn't a problem and when it is working everything seem to run fine. Sometimes I have to wait 1 day before it boots up, other times it takes 3-4 days. If the power cord is connected to the computer it seems as if the computer won't start at all (I am not completely sure about this though) regardless of how long I let it rest.

Please, has anyone of you any ideas?

 

[ApplejustWorks]

Is calling Apple about a replacement an option?

Just call up apple care and tell them that this is unexcusable for any product.

 

[MrMac123]

Same here!

I'm working on a friends iMac 1-gig 17in. machine and it has a very similar problem, it won't start unless I open the case and disconnect and reconnect something, almost anything, harddrive, DVD-drive, fan, power-supply, etc.
Once it starts it will start and restart all day long but if I turn off the power to the outlet (but leave the computer plugged in) it won't start the next morning.

This all sounds weird until we realize that probably all computers (including Apple and it's PMU (power management unit)) have something that controls all starting,restarting,sleeping,waking,and shutdown procedures.

I've had many PC's refuse to start until I removed, waited, and reinstalled slot installed components. Mac's don't generally suffer from this malady but I believe you and I have machines that have a leaky capacitor or some other faulty component (regardless of where it's located, motherboard, power-supply board, a bad stick of memory, or even a bad controller on the DVD drive) that's confusing or telling the PMU that there is some error and it should not start the machine.

If the problem is just a confused PMU it can be reset on a Mac by pushing the Cuda (PMU reset) switch (located in different places on different Mac motherboards) or remotely on some Macs (disconnect all cables and hold the power button while connecting the power cable then releasing and pressing it again. This is a good fix if there isn't a hardware problem but if there is the offending component will need to be diagnosed and replaced.

Which begs me to ask..... has any official Apple repair depot ever just replaced the fuse on a Mac power-supply board ($2.00 fuse + case cracking charge - Thank You Very Much!) or do they tell you the power supply is bad and they can install a reconditioned one for $300.00! And if they haven't then do they recondition yours (replace the fuse) and resell it to another sucker for $300 + parts and labor and whatever the traffic will bear?

Hope this helps a little and gives you a place to start.

-MrMac123

 

[Soulwar]

Hi,
I am a new member of this forum and I joined purely to see if I can find a solution to my startup problem. I first tried searching the net to see if I could find anyone having experienced anything simlar, but without being succesful.

My mac is an iMac flatpanel 17", 1.25Ghz, 512Mb SDRAM, 80Gb Hd. I also have an external LaCie 120Gb firewire drive and a Hp psc All-in-one USB printer. I purchased this computer for my wife's birthday 1.5 year ago and it worked like a charm the first 10 months. Over the summer, when we were on holidays, I shut the computer down and unplugged it from the wall. 3 weeks later when trying to boot the computer, it refused to start. No lights came on, no sound from the computer what so ever. After checking cables and unplugging all perpherials without any change, I assumed the internal power pack to be fried and I engaged the warranty and sent it to Apple for fixing. They changed the power pack and everything seemed to be working normally again. I had bad feelings about this though so I decided to purchase the extended Apple Care plan (another 2 years of warranty). 3 months later I had the same problem and the computer was sent to Apple again but the computer decided to start just fine as soon as it arrived at Apple. They kept it for a week trying to repeat the problem but in the end the computer was just sent back without any changes. Another 3 months passed and then I was facing the same problem again. The computer was stone dead and nothing was working. I unplugged everything and just let it rest for a few days... then it started again without problems. The problem occurs only when it has been shut down completely and only sometimes. Restarting (selecting 'restart' from the menu instead of 'shut down') isn't a problem and when it is working everything seem to run fine. Sometimes I have to wait 1 day before it boots up, other times it takes 3-4 days. If the power cord is connected to the computer it seems as if the computer won't start at all (I am not completely sure about this though) regardless of how long I let it rest.

Please, has anyone of you any ideas?

This is how to reset the PMU as mentioned. If it works, it's something to let Apple know.

Could also try the Apple Hardware Test. (Just looking for some validation you could use)
If you need the test.
http://www.info.apple.com/support/aht.html