20529 Views 1 2 3 4 Previous Next 59 Replies Latest reply: Jan 24, 2009 3:16 PM by bayswater Go to original post
I have spent many hours trying to get my G5 to function. The three flashing lights when powering up is dominant. I have been able to start up a couple times and I get 2.5 minutes of computing time before the screen freeses. Needless to say I am heart broken over this. I am currently on hold for Apple Support. I had thought Apple Support would review these posts and weigh in with a position. Wishfull thinking on my part. I'm afraid my future has $$$$ to fix the problem.
Finally got thru to Apple Support and what do you think their position is: Take your computer to your local Authorized Apple Service Center and have them run diagnostics. I insisted Apple has data on repairing this problem. What was the solution? Response: every computer may have a different cause so there is no common solution. I think that's crap. So my feeling that $$$$ outlay in my future is reality.
I've got the 3 Flash problem on a 2.5GHz water cooled G5.
I took it in to the local Apple dealer, same story, need a new Logic Board.
I saw your post, tried your solution and voila,computer works again. Both with the hair drier heating round the DIMM slots and the pressure near the right lowest of the Upper DIMM slots.
There must be lots more people that are suffering this problem but probably don't know there could be a solution much simpler than a new Logic Board.
Have you figured out or heard what the actual cause of all this is? There must be some simple and permanent solution that could well gain these lovely units years more life.
I've since bought an iMac, but can't in all good conscience sell the PowerMac unless I can get some permanent fix. I think your solution is ingenious but what is the pressure doing?
I keep thinking, this is something minor and stupid, but what?
Interesting... I finally got my system to start, but not sure how. I reseated all the parts and messed around with the power button too. As for the pressure point, below that part in the logic board is the heatsink tubing. Makes sense. I overlayed your picture with the bottom of my old logic board:
I'll try this when it happens again.
Brilliant! Initially, I found one of the two plastic rivets not holding that heatsink/component in its proper place. I repaired the rivet with no joy. Apparently, the component that it secures has the fracture in its traces or solder joint. The pressure only closed a gap, somehow. I heard rumor of one fellow with some sort of a soldering robot arm that can repair these mother boards. I've been told he's making a bloody fortune. I only assume that this fracture is caused by installing RAM and using ham-handed force to press the chips in. By the way, my Mac is still running flawlessly.
Great job! I could kick my self for missing a bid on ebay for a brand new replacement logic board. It closed at $34.00 - *$34.00*! I constantly monitor ebay for a deal on a new or used, working logic board. One that is working might last if one would take care and follow the precaution concerning overheating and undue pressure installing RAM. In any case my Mac is still running. If I were to purchase another LB, I would have a spare for the unforeseen inevitable, if you know what I mean.
Dave & Base 12
Thanks for that Logic Card super-imposition, deepened the mystery hasn't it?
I installed my extra RAM on purchase and haven't touched it since, 3 years later, kernal panic and oops, 3 flashes.
BTW, I found the trick with RAM installs is to have the retainer clips out fully, slide DIMM in, push side retainer clips in as far as they will go, then push DIMMS in at ends, one end at a time and it clicks nicely in place, easy peasy.(I've done a few since the 3 flashes appeared)
This micro-soldering of Logic Boards:- can anybody progress that from an urban legend to a URL?
I've read scary reports of needing a special temperature calibration program before you can get a reassembled Logic Board to function normally again. Is this true? What if I take the Logic Board out just to clean 3 years worth of muck out, do I need a thermal recalibration?(to stop the Mac behaving like a vacuum cleaner)
Man I'm glad I tripped over you guys, much better gen. here than my local Apple Dealer.
I tried this on a friends G5 that had the 3 LED flash problem. Before this I tried swapping out the ram with brand new ram, and still had the same problem. After applying pressure to the area that you specified, the computer would start up with no problems, but would either freeze after a bit of use, or return to the 3 LED blink after turning the computer off and trying to turn it back on.
So what kind of diagnosis is this if applying pressure temporarily allows the computer to run? will Apple do anything about this? or will it cost a lot of $$$.
No luck so far.
David Rolands' solution on this forum is the best I've found on line so far.
I think Apples' silence on this so far has been deafening.
I don't think the problem is due to ham-fisted Ram installations but is a design fault.
The problem appears to be a poor connection under the right lowest Ram bank.
At that position, on the other side of the Logic Board is some kind of heat sink, held in place by two screws. I think thermal cycling (expansion and contraction with heating and cooling of the sink as the computer warms up and cools down) has caused expansion and contraction of the area between the screws. I think this has caused a broken electrical connection on the RAM side of the Logic Board. This seems to be happening increasingly frequently now as these Macs age.
What galls me is that this is likely a very minor problem and easily fixed, but with the right gear, which almost no-one has!!
Does Apple think 3 years is an acceptable life on a box only which costs more than twice as much as your everyday entire computer system (complete with monitor)?
I've had a fabulous run with Macs up till now (some 20 years). Not sure I can recommend them now.
Well, I can confirm that it is not my RAM, nor do I need to clear NVRAM. Laying the computer on its side and pushing "the sweet spot" lets it boot and run fine.
I ran the Apple Hardware test and it reports that everything, including the Logic Board is fine.
I know it's not cause when I stand the machine up again, I get the 3 blinking lights.
This is really screwed. If I take it into an Apple shop they'll get me to spend $$$$ on a new Logic Board. I reckon it would be cheaper to get Steve Jobs to hold his finger on the sweet spot while I use my computer. I'll pay by the hour...
Where exactly have you applied the screw pressure?
I've tried building a little rig but have had no luck.....
Any more information on that character with the soldering rig?
I reckon as more and more of these Macs fall over the better the chance of an accurate diagnosis and subsequent final repair!