Why does my Mac Pro displays static and garbled junk on both displays?

January 13, 2010 12:56 PM

Please help me correctly diagnose this video/display problem on my 3-year-old, out-of-warranty Mac Pro.

My Mac Pro is out of commission. It's from November 2006 and the specs are: 2.66 ghz quad xeon, 2gb ddr2, nvidia geforce 7300gt 256mb, 1x500gb hdd, 1x1tb hdd, OS X 10.5.8. The chain of events is as follows:

1. In general, this computer is on 24/7.
2. For a few months, my Mac Pro tower would emit a single beep at seemingly random times. Never at boot time, but after the computer had been on for hours, days, or weeks. I foolishly ignored this because I could only find information about successive beeps at boot time signifying memory failure.
3. A few times over the past year, the system was unable to locate the startup volume. I'd reboot and everything would be fine.
4. Recently, for a day or two the computer would freeze up - one of the drives would spin up if I tried to open a file or launch an application. The spinning beach ball of death would appear and I would have to reboot.
5. Shortly after the system began locking up, strange artifacts would appear on the display. Weird lines, small spots resembling static or garbled lines and colors.
6. After a day, I could not even boot into anything usable as I would just see scrambled lines (like this) or solid blue screens with the spinning beach ball (like this).
7. At present, I can boot up and get to the login screen. A few small bits of static appear here and there. When I click on my user icon, I see the static.

I tried the following things without success:

• I have a bootable backup on an external disk. Using Option+boot I selected this as the boot device and replicated the problem.
• I tried to Option+boot and choose the OS X install disc, however my optical drive does not appear as a bootable option.
• I tried to Shift+boot into safe mode, but the system ignores the key press and goes straight into a normal bootup.
• Cleaned out the case with a can of compressed air.
• Removed the graphics card and re-seated it in a different PCI slot, then tried to boot up.

I don't think I'm dealing with a bad hard drive because:

• I can mount and read my boot-able external backup via usb on my MacBook Pro.
• Using the MBP, I can mount and read both of the Mac Pro's internal volumes over my home network.

This leads me to believe that this is a video problem. I find it unlikely that both of my cinema displays failed at the exact same time. Maybe this is a logic board error (I hope not), or just a bad video card? Or could I have some corrupt system files/video drivers.

posted by tomorama to Computers & Internet (5 answers total)

I had something like this happen on a G5 tower, it turned out the ATI video card was the culprit. It had overheated and melted the solder connection between the cooling fins and the solution was to get another one.

The pattern on the screen was similar to yours.

Could also be the corrupt video card drivers but the only way to test would be to boot up via holding down C just after your hear the boot up chime and install a clean fresh OS onto an external drive (or another internal drive) but I think its the video card.

From my experience if you are holding the key commands down when it chimes it will sometimes miss the commands from the USB keyboard (boot up sequence screwup) and it will boot normally. Try doing the key commands about 1 sec after the chime.
posted by boomcha76 at 1:05 PM on January 13, 2010

Response by poster: I'm using a BlueTooth keyboard. I will try your suggestion about waiting until after the chime.
posted by tomorama at 1:44 PM on January 13, 2010

Check for blown capacitors on the video card. Anyhow, it's a cheap fix to pick up a newer, faster, better, stronger video card. Apple will charge ~$400 for the old slow card...
posted by mmdei at 2:02 PM on January 13, 2010

Yeah, I suspect your video card is toast It'd be easy enough to beg, borrow, or buy a decent card and swap them to test.
posted by fairytale of los angeles at 2:39 PM on January 13, 2010

Probably a card issue. Could be RAM too maybe. If you have multiple RAM modules you can try pulling them out individually to test.
posted by bitdamaged at 3:57 PM on January 13, 2010