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dual 1GHz MDD won't boot OS X

I've got a dual 1GHz MDD G4 that is having some boot issues. It WILL:

-work in target disk mode (so was able to copy all the data off)
-boot in single-user mode
-boot a 9.2.1 install disk (but does not see the hard drive when I do this, and the installer says in won't run on this machine)

It will NOT:

-boot from the internal hard drive (10.4.3 before the system crashed)
-boot from the softawre resore disk (10.2.4) that came with the system.
-boot from a tiger install disk (10.4.3)

In all the OS X boot attempts, I get the grey screen with the apple and spinning gear going forever. Also, I can use the option key at power-up to see the hard drive or any CD or DVD in the drive and choose one to boot from. Zapping the Pram seems to have no effect.

Addtional info: when I tried to boot in verbose mode, I saw Bus errors or segmentation faults for syslogd, xgridagentd, and mDNSResponder. Also, in single-user mode, I see malloc errors with many commands (like ls and man).

I have not yet hit the PMU reset on the motherboard.

It appears that this system crashed back in January - late at night on a weekend. After that crash, it got progressively slower until last week when it would not boot. I found the log file from the crash and it appears to have taken 10 minutes (!!!) from the first problem in the log file until the system completely crashed.

I'm really not sure at this point whether this is a hardware or software issue???

Any ideas?

dual 1GHz MDD Mac OS X (10.4.3)

Posted on Apr 6, 2006 3:39 PM

19 replies

Apr 25, 2006 9:50 PM in response to power mac user

Power Mac User,

Hopefully you see this - got a possible suggestion for fixing your dual G4. Try removing the processor module and then reseating it. (You'll have to take the heatsink off, clean off the old thermal compound and apply fresh before putting it back on.) I just tried this on my MDD G4 and the second processor started working again. Dunno if it's a permanent fix yet, but it's definitely promising!

You can get the MDD Service Manual (full instructions on how to remove every part in the machine) at this site:

http://www.eserviceinfo.com/equipmentmfg/Apple23.html

(Grab the file PowerMac G4mirror.rar)

Hope this helps!

-Robb

Dual-1.25 GHz MDD G4 Mac OS X (10.3.9)

Apr 26, 2006 6:51 PM in response to The Lab Guy

... and if the rar file won't open, I have the manual in zip format here. (Clicking the link will start an immediate download.)

Gary

May 1, 2006 8:22 AM in response to The Lab Guy

Ok, I can confirm the cause of the trouble with my machine - some sort of loose connection between the CPU module and the motherboard. Dunno how or why this spontaneously developed, but it's definitely the culprit.

I've jury-rigged a fix that seems to be working so far. Basically I shored up the end of the CPU module opposite the connector so that when you tighten down the heatsink, it doesn't act like a lever pulling on the connection. So far so good - both processors working, Level 3 caches showing up, and I can read the temperature sensor again. I just hope the connection doesn't further deteriorate with time.

Power Mac User, I hope you're still out there and see this - a couple spacers could save you $800 on replacing the CPU module! (I actually wonder if this was the cause of my first CPU module "going bad", which was replaced under warranty.)

-Robb

Dual-1.25 GHz MDD G4 Mac OS X (10.3.9)

May 1, 2006 1:32 PM in response to The Lab Guy

Robb:

Thanks for posting back with this info! I hope that the jury-rig holds for you forever!

Gary

dual 1GHz MDD won't boot OS X