PowerMac Shut Down Automatically And Loud Fan - Faulty RAM?

ian27 · #1 May 7th, 2009, 01:24 AM

Hello guys,

This is the first time I have posted here. I have a PowerMac G5 Dual Processor. It is about 3 years old.

Over the last year I now and again get this strange this happening where the computer would freeze and the fan would come on at full speed and be very loud. It also started happening when I turn off the computer for a while and turn it back on again. It would not start up and the fan would just kick in. The only way I could get it going was to manually turn the machine on and off until it would eventually turn on properly. Sometimes I would have to do this 4 or 5 times.

Then today the computer just turned itself off automatically. No warning, nothing, just click and off like when you have a power cut, but there was no power cut.

So I ran a quick hardware test from the OS installation disk and it said that it detected 2 faulty RAM sticks at startup. I was worried it might be a logic board problem but that has come back on the test saying it is okay.

Would having faulty RAM cause the above to happen? And how reliable is the hardware test that comes with the Apple OS installation disk? I am praying it is just RAM and nothing more expensive.

I am gonna clean out the fan today, and dust things down a little bit just in case it is a bit of dirt or something, but I would be interested in other people's opinions.

Thank you in advance,

Ian

**Giaguara** · #2 May 7th, 2009, 01:29 AM

AHT is pretty reliable.
Faulty RAM can cause that, and it's possible it worked for so long and then just wend bad after all that time. If in doubt of the test, run it again, in loop mode and overnight. It should come with errors again related to the memory.

ian27 · #3 May 7th, 2009, 02:00 AM

Thank you so much Giaguara. How do I run it in loop mode? And faulty RAM can even cause the computer to automatically shut down on occasion?

ian27 · #4 May 7th, 2009, 05:09 AM

Well I took everything apart, cleaned it, and clipped it all back together again. The AHT then said that the ram was fine. Not sure how accurate that is. But I have recently had the mac shipped from my old home is Australia back to Europe so maybe something had come loose during transit.

I did a couple of other tests and it showed an error with the logic board which made me panic a bit, but for some reason the fans were not blowing on full whilst running the AHT. So I checked everything again, pulled it apart, clipped it together a second time, and now everything is passing the test with the fans are running correctly.

I also found when I picked the mac up with customs again they had pulled it apart at some point because some things were still left not clipped in. So I am hoping it is something as simple as this and now everything will work smoothly again.

Fingers crossed!

**Giaguara** · #5 May 7th, 2009, 04:17 PM

There's a tutorial for it in the FAQ part..
Basically, CTRL+L to get it to loop mode. Release from loop with same shortcut, or it quits if it finds an error. Sometimes with RAM problems - when the computer has been booting for years and only having smaller problems with applications, it can take hours to find the fault. So always extended mode, and looped, for evening or overnight.