From MacFixIt.com

PowerMac G5: No display at startup, more possible solutions

Yesterday we resumed coverage of an issue where some Power Mac G5's exhibit unresponsive graphics display after startup. When the issue manifests, the system appears to startup properly, but the display is blank and cannot be activated via keyboard activity or any other procedure. We also identified a potential solution: disconnecting the unit's the power plug for a short time, then re-attempting startup.

We've since received word of some other causes for this issue, along with their corresponding solution.

Tabin Dickerson reports that his display card was loose, and re-tightening its installation resolved the issue:

"I have had the same issues with my year-old Dual 2 GHz G5 w/ 20" Cinema Display where there is no display after startup, even though the power is on and the display has the power light functioning. After looking through the Apple Knowledge Base, I found an entry with a similar problem. The solution... a loose display card. It recommended opening the case and making sure the card if firmly pressed into the slot. It's happened twice so far, and both times, this has brought the display right back."

Meanwhile, another MacFixIt reader reports that this problem only occurred with the presence of the available ATI Radeon 9600 XT card. Replacing the ATI card with a model from NVidia resolved the issue.

He writes:

"I had the same problem with a number of G5's and finally resolved it by replacing the video card. This problem was with the ATI card. I never had the problem with any of the G5's with the NVidia card. The problem has not returned since the replacement of the card."

i do not think it is the graphics card at fault, as i had the NVidia card and it happened to me

i put the problem totally with the OSX 10.3.6 system software, never had any problems after that with 10.3.7 & 10.3.8

at the time, i turned off the G5 for ten minutes, but this did not fix the problem, lucky for me i had a second hard drive, and i started up from that, after wiping the other drive and reinstalling 10.3.1, and updating it with the '10.3.6 combo' the problem was cured

If you are having this intermittent no-video-at-startup issue, please do me a favor and send me a PM - a particularly helpful Applecare rep has been helping me troubleshoot the issue and even after leaving it with my local Apple store for two weeks, having nearly every part of the computer swapped save for the power supply (that's happening this week), and having every diagnostic test available to Apple looped for 24 hours at a time (AHT, AST & dedicated memory test) they are all sort of stumped. At any rate, this particular Applecare rep has been super, super helpful and he said I could ask fellow users having the same problem submit thier details to him to see if any common element can be found. Anyhow, if you have this particular issue and have a minute to write down your details, including: an explanation of the problem as you experience it in as much detail as possible, your model number of PowerMac G5 (seems to be exclusive to the PowerMac G5) and any and all peripheral items you have installed. Once you've collected the details, just PM me and I'll supply you with his email address and the Case Number under which you should submit the info. I'll definitely share any info that comes out of this - thanks in advance!

Hi!

I've had this exact problem for a while now. And I finally find a post in a forum that seems to be similar!

Dubster, feel free to send me a PM, but I prefer to post the description here first so everyone can share.

Here's the situation:
PowerMac G5, 1.8GHz, first generation
Graphic Card: ATI Radeon 9600 Pro (ATY,RV350, according to system profile)
Samsung SyncMaster plugged on DVI (no difference if I use VGA + Apple Adaptator)
System: Mac OS X 10.4.8 (no difference with previous 10.4.x or 10.3.x)

Symptom:
The mac usually start "correctly" the first time: hard drive works, things happen, and when I feel like startup is finished, I can use keyboard and mouse (like, using shut down button from my Logitech keybord, hit "enter", and the computer does properly shut down. That's pretty much the only thing I like to do in this situation)... but... WITHOUT ANY DISPLAY. The monitor doesn't get any signal (but unplugging the cable prints a "check cable" message => so the cable is properly plugged).

Where it seems to get different from you is:
Usually, when I start it up again (because I feel like using a computer is more friendly with some kind of display), things go worse: the hard disk doesn't seem to wake up, and pretty much nothing happens.... UNTIL the fans start making more and more noise!! At some point (approx. 5 mins), the mac is making as much noise as an aiprlane. Anyway, you don't have much choice except shutting it down (with the front tower button).

This same situation ALWAYS happens on wake up from suspension.

It usually happens like that:
- first, proper startup without display
- "proper" shut down
- second startup: nothing + creazy fans
- then, 1 to 3 of the above
- and finally, the thing goes back to normal

I have no clue about what is causing that: I did properly re-install OS X a few times, no change. I removed some RAM, nope.

The creazy thing is: the Mac worked just great for approx. 2 years. Then this happened. Then it left!!!! And it's been back for approx. 3-4 months. Any link with ambiant temperature???

It's such a pain: it works so well once you've passed this #$$££ls breaking startup thing!!! And I can't use the energy save functions because I know it will crash at wake up anyway...

I don't mind changing the video card, but I don't need it and I would like to be sure that's the solution...
I tried putting the video card back in order but no luck.
I have to say the other day, the Mac was working properly, I accidentaly hit it, and bow, no more display. No way to have display back until I rebooted. Maybe I should consider re-tightening the video card again.

Hope you can help...

Olivier

PS: one more creazy note: tonite, when this happened (as usual), I tried to open the case. You know how G5s start having fans to maximum when you open them? Well, here (second situation-the mac doesn't start up and eventually fans like creazy), that was the opposite: when opening the translucent part, fans went slower. Putting it back, they went back to maximum. You said, bizzare???

I'm using an original dual 2ghz Power Mac G5.

I have had a blank screen issue similar to what's been described here. Startup seems normal, but the screen is blank. It often returns after resetting the PMU or PRAM, but not always.

My problem began with crashes at shutdown. The next time I tried to start up I got the blank screen.

Then I started getting the Blank screen without the shutdown crashes.

Took it in to get looked at, but the thing worked fine in the shop.

Figured out that temperature might be a factor, began heating the case with a blow dryer, and it worked fine for a few weeks.

It took increasingly more heating time to get the screen to come on, and now when it starts up I don't even get the chime. The status light comes on and blinks three times every 5 seconds.

Took the computer to the Apple store and it started up fine.

Took it home and nothing, no startup chime, status light blinks 3 times every 5 seconds.

Got it to chime a few times with one entirely normal startup in the last three days, though I've turned it on maybe 50 times in that same period. (I had the door off, but the wind deflector installed when it started up normally, but that result wasn't repeatable.)

Hopefully my situation isn't the future of your computers, because it just keeps getting worse for me. Any advice is appreciated.

Is you computer connected directly to AC power, or is it on a UPS? How old is the building where you live? Do you ever have any power problems?

The house was rewired about 8 months ago. There have been no power problems. The computer is currently plugged directly into the wall.

I managed to get the thing started earlier this evening and switched the startup disk. It started up a number of times consecutively, but a few hours later, nothing.

Two suggestions:

1. Buy a UPS. Never plug your G5 directly to AC power. In addition to protecting your computer from power events, you may learn something about the quality of your local power grid. When I lived in Southern California (1997-2005) I had constant power problems. The UPS solves all of them. There are many brands on the market. I like APC. It needs to be fairly large for a Power Mac G5. Mine is 800VA.

2. Remove and re-seat every card (Video, RAM, etc.) in your computer. Corrosion of the edge connectors on plug-in components can cause intermittent problems that are nearly impossible to diagnose. Do the same with your cable connections on the back of the computer. Unplug, wiggle in and out, replug. When you are done with this, reset the SMU and PRAM.

3. Boot from the OS X DVD.

4. Post back and tell us what happens.


And more questions:

1. What is the model number of your G5?

2. What make/model of display are you using?

Hi folks,

I found this: http://docs.info.apple.com/article.html?artnum=32473

Apparently, this is a know problem with ATI 9600 on some G5s.
I know people have had their video card replaced in France (you guessed the warranty is dead for a while). I called them today and have to run a "hardware test" before they can reply to me.
With a bit of luck, I'll tell you tomorrow that they are sending me a new card...

Olivier

Hopefully that will work out for you, but I'd already done this step a while back and mine isn't that model, plus, Apple has already replaced the the video card once. I get the feeling, more and more, that the problem has something to do with whether the temperature sensitivity/power management of the G5. Either way, I hope you have sent an email to the Applecare rep I gave you the info for - he's been very good about sticking with me on this, trying to get to the bottom of this, and up until recently, I had only been able to find one other user to send in thier info on what's going wrong - with more info from info, perhaps he can find the common denominator or at least determine that the issues we are having are not all due to the same thing.

Dubster

Hi,

Sure I will write to the guy. I will even probably spread your message to the people on the french forum.
I just want first to try everything to solve it.

Just one thing that might particulary interest you: the thing I thought was very weird is the fact that the bug appeared and dissapeard for a few months, then reappeared.

Look at what the guy says here: http://www.macfixit.com/comment.php?mod ... &pid=12259

It's like the video card has to reach a specific temperature before to work. That sounds REALLY interesting because I almost get the bug during winter only....

Olivier

Hi All.

Seems I'm in the same boat. G5 dual 2.0.
It is one of the first ever produced.
Symptoms are: No chime at startup.
Fans go into overspeed
No startup screen
Replaced ATI 9800 With X800 (original upgrade OEM)
I swapped out original 2*256 and 2*512 ram chips.
Tried to boot with either of the sets(no luck)
Removed battery and checked voltage(good)
Tied reseating video card(nochange)
I have a question though. I also run a 20" isight Imac
on a lan with the G5. Is there any way to remove the video
card from the G5 to try to get it to boot and use it as a server of sorts.
There are some files I would like to get off of the G5.

Sounds like you did most of the troubleshooting steps. Since the fans are spinning and there is no startup chime, it leads me to a logic board issue.

You could try resetting the PMU:

1. Shut down G5 and disconnect everything including the AC power cord.
2. Press the PMU button (little black button) located on the logic board just below the RAM and beside the power supply connector.
3. Only press it ONCE, you can damage the logic board.
4. Wait at least 10 seconds and then reconnect only the power cord, display, keyboard, and mouse.
5. Startup the G5.

If it will not start then, it's probably the logic board. The G5 will run without a video card, but then you wouldn't have any way of knowing whether it is working correctly, unless you had already setup Apple Remote Desktop or some form of VNC or remote login.

As always, perform at your own risk and take the appropriate anti-static precautions.

C

Thanks Cory

I did reset the PMU before, forgot to mention that.
The only reason for the question on the video board
is to see if it might be causing a Kernel panic. I live four hours
away from the nearest Apple support so the more I can try
myself the better. I think you might be right. My list of probable causes
is getting shorter and the logic board is still on there. It will be over $1000.00 CDN if I'm lucky. I might have a real nice Aluminum doorstop/
bookend yet!

Any activity on the logic board red LED...constant on, not on, flashing?