G5 Ppc Black Screen


My G5 2GHz Dual Core [M9590LL/A] ID= PowerMac11,2 has suddenly developed an issue where the screen goes randomly black.


6.5 gb Ram

OS 10.5.8

Cinema Display 30" [M9179LL/A]

I first saw the issue when Mail 3.6 would check for mail, but then it happened totally randomly during scrolling, dragging windows, and even not touching the computer.

The computer boots fine to login & desktop, and then you wait for it to happen. Could be in 1 minute or 1 hour. It doesn't seem to be tied to any activity.


- Replaced the PRAM battery

- Zapped the PRAM

- Reset SMU button

- Logged in under different user

- Disk Utilities

- OS Archive & Install 10.5

- Update 10.5 to 10.5.8


- Hooked up the monitor to another computer, and it is fine.

- Boot in Safe Mode = 100% stable, unfortunately it's not a very usable computer with the items that Safe Mode disables, but everything works.


When I did the OS reinstall MAIL wouldn't recognize my mail accounts, even though it was all in the MAIL folder. It treated me like a new user "would you like to create new accounts" dialog. So I manually re-created all my accounts. From this point forward I am receiving new mail fine, everything previous has been totally hosed.

- Mail in wrong box

- Mail that won't delete

- Duplicate mail in one or more boxes

- Mail with no content, even though if you look at the .emix files in the MAIL folder the content is there

- I read in the forums about MAILBOX > REBUILD. I tried it on one box and all the mail in that box disappeared! So I won't be touching that again.

In the +25 years I have owned, and maintained Macs I have never experienced this many unsolvable issues, so hopefully one of you smart folks can point me in a direction.

PS - I'll save you the comment "just get a new Mac", as this computer contains ±10k of important PPC software.



Rosie Moderator
Staff member
Your specs are not telling us the model of your Mac. Is it an all in one or is your monitor separate? It could very well be your monitor going south, which can happen due to age.


@ Cheryl - OP does show that the system is a Late 2005 PowerMac G5 (PowerMac11,2)
That's also the first PowerMac that uses Dual Core processors. Earlier models did not have multiple cores, just multiple processors.
OP also said that he tried the monitor on another computer, where apparently it worked fine.

SysGeek - have you tried reseating the graphics card in its slot? When you have it removed, check that the heat sink, or fan, if the card has one, is clean, and clear of dust.
I would still be suspicious of the graphics card - 10 years old, eh?