iMac G5 (iSight) do not start up (A1145)

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YiANNiS-GR Author

Level 1

0 points

iMac G5 (iSight) do not start up (A1145)

The computer (iMac G5 20") was working perfectly for the last 8 years.

I shut it down on Friday and on Monday could not started up. Dead!!!

I open it and changed the PRAM battery, just in case, but the problem still persist.

(http://www.ifixit.com/Guide/Replacing+iMac+G5+20-Inch+Model+A1145+PRAM+Battery/1 153/1)

Now, I have notice that the power supply was making a noise (tik-tak-tik-tak, tic-tak...) but after I did try many many many resets to the SMU (http://support.apple.com/kb/HT1767) since then is just making a very very low continues noice.

After doing some research I found out that there are 4 diagnostic LEDs on the logic board under the right speaker.

(http://support.apple.com/kb/HT2831)

In my case LED No1 is ON while the computer is OFF.

After the reset LED No2 flashed for half a second, the fans were just moved for half a second but still the computer can not be started.

Any idea what would be the problem?

I guess the problem is the power supply, but before I go out there and buy a replacement, I would appreciate any help from anyone who either experience the same problem, or knows anything about it.

Thank you in advance.

Posted on Oct 1, 2013 12:20 PM

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Answer 1

Feb 13, 2014 1:58 PM in response to YiANNiS-GR

Hi There:

Did you ever resolve your iMac problem? I have the very same issue... and seek a solution myself.

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Answer 2

Klaus1

Level 9

52,749 points

Feb 13, 2014 3:00 PM in response to emilycat99

iMac G5: Fails to startup

http://support.apple.com/kb/HT2173?viewlocale=en_US

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Answer 3

YiANNiS-GR Author

Level 1

0 points

Feb 13, 2014 3:06 PM in response to Klaus1

HI,

This article does not apply to iMac G5 (iSight) computers.

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Answer 4

YiANNiS-GR Author

Level 1

0 points

Feb 13, 2014 3:28 PM in response to emilycat99

Hi,

I did resolve the problem.

It was as I expected the power supply.

But apart from that, since the replacement power supply that I bought from ebay, was also faulty, I had to take it to a technician to replace the faulty capacitors from one power supply and soldered to the other.

As a result, I was not present at the time of the replacement, and he told me that a capacitor (?) was also faulty in the logic board of the machine, and he had to fix that as well.

The machine is working fine since then.

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Answer 5

Feb 14, 2014 9:04 AM in response to YiANNiS-GR

Hi

There is a great deal of confusion regarding the 1st and 2nd generation of iMac G5's ... you probabkly realized that also. I went to YT for instruction on how to crack the case - and it is like night and day and of course in the case of the iSight model is much more difficult to access the guts of the machine.

Hats off to you for resolving the issues.

I am reluctant to sink a ot of money into this machine - but I am attached to it .. i purchased it at the Apple Store for $1500 or so in the Spring of 2006 and used it for about 2 years only .... it has been idle mostly as I use macbooks...

If it just the power supply that sees like an inexpensive fix - but if a capacitor is bad ... wow i really don't want to go there...

The tic tac noise - was that caused by the faulty power supply?

I have an install disk jammed in the drive - do you or anyone else know how to remove a disk from this iMac which does not boot?

regards, Jay

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Answer 6

YiANNiS-GR Author

Level 1

0 points

Feb 14, 2014 11:25 AM in response to emilycat99

If you follow the instruction of this link

(http://www.ifixit.com/Guide/Replacing+iMac+G5+20-Inch+Model+A1145+PRAM+Battery/1 153/1) you will easily open the iMac.

The only tricky thing in the whole process, is the point when you have to open the iMac case with the plastic card. Take your time.

You will manage it.

Because you saying you did not use the iMac for a long period of time, check out the PRAM baterry. Just in case. Mine was really completly charged after so many years!!!!!!!!!! Like a new one!!! but I did change it. Obviously you will have to take everything out of the case since the battery is located under the logic board!!!

Yes, the tick tack noise was from the power supply.

But accoring to my technician, the failure of the power supply was the reason for damaging the logic board.

In any case, you have to open the machine, in order to check the 4 diagnostic LEDs.

From there you can decide if you are going to fix it or not.

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Answer 7

Feb 14, 2014 12:22 PM in response to YiANNiS-GR

Thanks again. I can definitely invest in a new PRAM battery and see if that makes a difference..

I disassembled everything a few days ago after having watched a video on YT. I had actually bought a new HD thinking that I could just pop that in. Of course the new HD did not have the attachment on the side for heat measurement, hmmm.

I will look at the 4 diagnostic LED's also.

Of course I had also recently upgraded to the 4 DRAM. and upgraded software to 10.6.8. It was a nice relatively

fast machine for a few weeks before it crashed and burned. (i wonder if those upgrades hastened its demise? as in stressed out the capacitors?)

thanks again

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Answer 8

rccharles

Level 6

12,957 points

Feb 15, 2014 11:53 AM in response to emilycat99

but 10.6 will not run on a g5.

upgraded software to 10.6.8.

Find out what machine you have.

This site provides more information. Best for older machines. Note, serial number is sent in the clear.

"A serial number is a unique, identifying number or group of numbers and letters assigned to an individual piece of hardware or software. It's used for various things depending on the product / brand but what is your Mac's serial number for and more importantly... what is it hiding and what can it do for you ?"

http://www.appleserialnumberinfo.com/Desktop/index.php

or

This site provides more information, but lacks security too.

"A serial number is a unique, identifying number or group of numbers and letters assigned to an individual piece of hardware or software. It's used for various things depending on the product / brand but what is your Mac's serial number for and more importantly... what is it hiding and what can it do for you ?"

http://www.appleserialnumberinfo.com/Desktop/index.php

http://www.chipmunk.nl/klantenservice/applemodel.html

( hint by K Shaffer )

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