migrated mac either boots flawlessly or not at all
July 14, 2011 12:34 PM   Subscribe

Macfilter: I have an iMac G5 with osx 10.3.9 that would fail soon after startup because of bad capacitors. I ordered a used replacement running osx 10.5, which booted up fine (the first time) and I was able to transfer all my files and programs from old to newish using target disk mode and migration assistant. After migration the programs worked but when I tried to reboot the new(er) iMac would power down immediately after or sometimes during the initial start. Nothing is displayed. About one in 15 tries boots up normally. I'll try the hardware test the next time I get it to boot, but this problem seems unlike others i have read about. Any ideas?
posted by drzz to Computers & Internet (13 answers total)
Was the machine consistently starting up fine before you migrated your stuff? If so, you've probably got something weird loaded up on your old iMac, and you've managed to transfer it over.

It sounds ridiculous, but there's definitely nothing untoward in your Login Items (System Preferences - Accounts)? If you make a new user account and boot into that one, does it still happen?

What happens if you do a Safe Boot?
posted by Magnakai at 12:44 PM on July 14, 2011

Response by poster: The hardware test didn't happen because my old comp's disk wouldn't initiate it on the new one.

I'll try safe boot, but I think the problem is surfacing before boot time - during the opening chime. When it boots, everything works. When I hold shift and press power when it's not booting, I get the same result as if I had tried to boot normally. A quick power down, then nothing.

Any ideas for things to try if I get it booted into safe mode?
posted by drzz at 12:52 PM on July 14, 2011

Do the safe boot, and if the problem goes away, then insert the OS disc, reboot, hold down the C key to boot from the optical drive, and run the repair option in Disk Utility to see if the hard drive has disk errors.

If Disk Utility shows unfixable errors, back up your data (you do backups, right?) and reformat the hard drive before reinstalling the operating system.

If there are no unfixable disk errors, do a clean install ("Archive and Install" option) when reinstalling OS X.
posted by Blazecock Pileon at 12:54 PM on July 14, 2011

Are you sure the replacement doesn't also have bad capacitors? This was such a widespread problem at the time it's quite possible that it does.

I ordered a capacitor replacement kit from eBay and did my own replacement rather than buy a system board. Probably not an option if you aren't comfortable soldering/desoldering.

When I opened up the iMac about 1/3 of the capacitors had blown. I replaced all of them anyway since it's so hard to tell good from bad before they fail.
posted by tommasz at 12:57 PM on July 14, 2011

Response by poster: In answer to Magnakei's first question question. I only started it once before migrating. And the times it has started were times after which a least a few minutes had passed since it had ether been shut down or attempted to be booted. I'm thinking it could be a power issue.

Blazecock, when the problem is occuring, it does not even start to boot up no matter which keys I'm pressing. I hear the chime (which seems to be truncated), a click and the lights go out. Nothing is ever displayed on the screen.
posted by drzz at 1:01 PM on July 14, 2011

Response by poster: Tommasz, I looked at the capacitors and they seem fine - no bulging or leaking like other bad ones I've seen. They still could be bad, I guess, but the symptoms are far different than those of the old G5.
posted by drzz at 1:03 PM on July 14, 2011

I hear the chime (which seems to be truncated), a click and the lights go out. Nothing is ever displayed on the screen.

Sounds like a hardware problem. If you're comfortable removing the back cover and you have the correct model, perhaps resetting the SMU would help.
posted by Blazecock Pileon at 1:12 PM on July 14, 2011

If the caps are good, you can't find anything in software and SMU has been reset (per BP's link) you might want to consider replacing the power supply. When I was looking for answers to my G5's issues, that was the second most frequent thing mentioned (after bad caps). Bonus: no soldering!
posted by tommasz at 1:15 PM on July 14, 2011

Response by poster: Thanks for the advice, guys. I'll let you know how it goes.

A power supply is definitely not as intimidating as molten metal.
posted by drzz at 1:19 PM on July 14, 2011

My hunch: +1 on power supply failure.

posted by krilli at 1:46 PM on July 14, 2011

Yep nthing the power supply is bad. Pretty classic symptoms for these models.
posted by BryanPayne at 2:43 PM on July 14, 2011

Here is Apple's diagnostic for a failing iMac G5 power supply.
posted by Blazecock Pileon at 2:47 PM on July 14, 2011

Response by poster: I'm nonplussed to report that the computer has now booted several times in a row without a problem.

The only change I made was an attempt to reset the PRAM, but it has failed multiple times between the reset and the current streak. I guess I'll keep monitoring it.

Thanks again for all the advice, I have a feeling it'll be useful when the problem returns.
posted by drzz at 4:01 PM on July 14, 2011

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