09-21-2011, 02:22 PM

I purchased a used iMac G5 (2 GHZ Power PC, 2.0 GB Ram, Non-iSight 20" model) expecting either the board or screen to be dead. The screen isn't without flaws but the unit starts to boot but hangs in 5-10 seconds on the spinning dial (white/gray screen with Apple logo).

I tried to install OSX from a DVD but the same thing occurred. Then, I connected it to a 17" PowerPC G5 to mirror/image the hard drive (OSX 10.5). That was successful but it doesn't boot on its own. The other computer can boot from this one but this one wont.

I tried removing the ram to see if 1 of the sticks was bad but unless they both are, that wasn't the problem. I don't know anything about Mac's so any suggestions will be appreciated. I don't see anything obvious from removing the back but don't really know what to look for. I'm guessing that the HDD and the ram are fine--maybe 1 of the boards is problematic. Any suggestions?

09-21-2011, 02:29 PM

Originally Posted by transgression

I tried to install OSX from a DVD but the same thing occurred.

Then, I connected it to a 17" PowerPC G5 to mirror/image the hard drive (OSX 10.5). That was successful but it doesn't boot on its own. The other computer can boot from this one but this one wont.

- If this iMac will not boot from it's own internal HD
- If when you boot from the OS DVD...you cannot do anything with the iMac's internal HD (install the OS)
- If this iMac will boot from an external HD

Unless I'm misunderstanding something...it seems pretty clear to me that the iMac's internal HD is dead. Sounds like the iMac needs a new HD.

- Nick

09-21-2011, 02:47 PM

Thanks Nick. Another computer boots from this hard drive. I didn't try booting this one from another. That's why I think it isn't the hard drive.

09-21-2011, 02:52 PM

Originally Posted by transgression

Thanks Nick. Another computer boots from this hard drive. I didn't try booting this one from another. That's why I think it isn't the hard drive.

Ok...so if I understand correctly...the HD from the "problem" iMac will boot a 2nd computer...but not the "problem" iMac" that it was initially installed in.

You did mention that you expected this "problem" iMac to have display and/or logic board problems. If this computer has logic board problems...that could certainly be the cause of "not-booting" problem.

- Nick

09-21-2011, 03:11 PM

yes, I agree about the logic board. The reason I expected a problem was (1) the price was such that I figured it must be non-working, and (2) the most common problems that I was aware of was bad boards and then bad screens. I don't know what a 'bulging capacitor" is supposed to look like, but if I take it literally, mine look fine (I don't see any bulging). I could try different ram altogether but didn't think that was the problem. When I run some of these tests (Cmd Opt and various keys), there is a lot of text on the screen with 'this' failed or 'that' failed. Most have to do with Power. Is it possible that a bad power supply could be the problem? Doesn't seem likely to me.

2 other things....1) I just tried it with the optical drive removed (to see if it made any difference). I had the back off and could hear the HD spinning and doing things that sounded like loading even though the screen was stuck on that spinning dial--which was frozen and no longer spinning. 2) Is your photo showing a Newfoundland? Maybe it is a lab or similar dog.

09-21-2011, 03:14 PM

Oh, for clarification, my son connected his 17" PowerPC iMac G5 and cloned the hard drive (or similarly copied the OS). This was done via Firewire cable. He then told me his computer was booting off of my. So, when he computer was going through all of the initial start-up questions, he told me it was really my hard drive. I spell this out so that it is clear that I didn't take the HD out and put it into another unit. And, I could be wrong in my interpretation but that is what I understood him to say.

09-21-2011, 03:23 PM

Originally Posted by transgression

yes, I agree about the logic board. The reason I expected a problem was (1) the price was such that I figured it must be non-working, and (2) the most common problems that I was aware of was bad boards and then bad screens. I don't know what a 'bulging capacitor" is supposed to look like, but if I take it literally, mine look fine (I don't see any bulging). I could try different ram altogether but didn't think that was the problem. When I run some of these tests (Cmd Opt and various keys), there is a lot of text on the screen with 'this' failed or 'that' failed. Most have to do with Power. Is it possible that a bad power supply could be the problem? Doesn't seem likely to me.

When we're talking about buying "busted computers"...and then trying to get them working when we get them...there are all sorts of things that can be wrong with them. It sounds like you've tried most of the common things:

- pulling the ram & trying one stick at a time
- booting the HD on another computer
- trying to boot the computer from an OS install disk
- etc. etc.

If you've isolated/determined that the HD, CD/DVD drive, and ram are good...there's really not a whole lot left other than the logic board to be bad. And if it's a bad logic board...well...unless you can get another one super cheap...forget about it. You've got a parts computer, a BIG paperweight, or a door-stop!

- Nick

p.s. Other simple things to try:

- try resetting the PRAM
- check the PRAM battery to see if it's dead or not. And maybe try replacing it if you want.

09-24-2011, 01:25 AM

If the firmware on the HD is messed up it may not run the (Broken) machine, but has the universal firmware may boot a different Mac model. Disconnect the HD and try to boot from the start up DVD...the machine should run off the DVD ...you will see the installer window. Let the machine run and see what happens. If it shuts down or the video freaks out you may have a board issue. If it was mine I would install a Clean HD and try to reinstall the OS. Be carefull not to break the heat sensor should you ever remove the HD and replace it.

09-24-2011, 12:25 PM

Thanks MacSK. It doesn't book from hard drive or from DVD (I did try a different HD, too). Obviously, something is wrong--likely one of the boards. If there was a way to determine which one, it would make the repair a cheaper endeavor (rather than replacing each board until the culprit is found). Occasionally (such as when restoring PRAM or a hard reset), the boot will get past the Apple screen and will hang with a dark screen and an arrow-pointer in the upper left corner. At that point, if I move the mouse, a 2nd pointer appears on the screen and will respond. But that is it. Not sure if that helps anyone. Thanks for all of the feedback.

09-24-2011, 12:33 PM

Your first post has me confused. Is this for sure a 20" WITH isight camera? a 2.0 with 2 sticks of RAM is not an iSight model. The iSight 20" has one DDR stick under that bottom panel and one RAM chip soldered to the Logic Board. Also the iSight model is 2.1Ghz.

Reason I ask is my 2.1Ghz 20" iMac G5 did that same thing but it would boot from the DVD. Turned out some of those famous bad formula Capacitors burst on the Logic board and also messed up the internal SATA controller. I could get it to boot from an External Firewire 400 drive but not the internal.

09-24-2011, 01:02 PM

Originally Posted by transgression

...something is wrong--likely one of the boards. If there was a way to determine which one, it would make the repair a cheaper endeavor...

How many "boards" do you think there are in an iMac? Typically...there's one board (the main logic/motherboard)...and that's it. Yes...sometimes there may be a really small daughter-card or small accessory board...but usually there's just one "board".

That's why when there's a logic board issue (financially speaking)...it's not worth trying to get the computer running, since a replacement logic board is too expensive (unless you can get a cheap used working one).

- Nick

09-24-2011, 01:08 PM

You are correct. Mine is an early model G5 and does NOT have iSight. I need to try to edit that part. Maybe the problem you incurred is my problem. Thanks!

09-24-2011, 01:09 PM

*****correction****** it is not the iSight model. It is the first or early gen G5

09-24-2011, 01:39 PM

Originally Posted by transgression

*****correction****** it is not the iSight model. It is the first or early gen i5

WAIT...WAIT...WAIT...WAIT...WAIT!!! There's a BIG BIG difference between an iMac G5...and a 1st or 2nd gen. iMac with an "i5" cpu. Only like about 5 years!!!

In your original posting you said you had an..."iMac G5 (2 GHZ Power PC, 2.0 GB Ram, iSight 20" model" (a 2005 model computer)...now you say you have a 1st or 2nd. gen. iMac "i5" (which would be a 2010 computer).

The iMac G5 (if working) would be worth about $200 bucks...the iMac "i5" from 2010...is probably worth closer to $800-$1000 (if working). So what do you really have?

This is like saying you had a Ford Escort from the 1980's...and now telling us you have a 2010 Ford Mustang!

- Nick

p.s. Heck...if this is a 2010 model computer (iMac i5)...it could still have Applecare on it)!

09-24-2011, 01:40 PM

Originally Posted by transgression

*****correction****** it is not the iSight model. It is the first or early gen i5

Just to clarify for others that might try and help, it's the 20" Ambient Light Sensor iMac G5 20". There was a 1st Generation iMac before it that did not have the ALS. The 2.0 Ghz 20" was the ALS. The older one had a 1.8 I believe. After your model they totally changed the iMac G5. The whole board is a totally different design.

This issue I described seemed to happen to a lot of the iSight models which had a totally different Logic board. On the 20" ALS there were some capacitor issues. You can tell if that is your issue by removing the back. Look at the large stand up Capacitors with the silver top. Is the top Bulging out or even worse, leaking?