LED flashes 3 times

Hrmmm - no delete option for accidental/twitchy posts ?!

Baffling.

Holy moly! This HAS to be my issue. Im glad I browsed through this thread. I'll try it and post tonight. I never touched my RAM prior to this mess, so the temperature fluctuation theory sounds very appropriate.

I too did the "hair dryer" method and it worked for about 3 automatic startups. Now when starting up, the gray apple logo appears and just keeps spinning. The fans are also turning high speeds. I really think that we are all having some sort of "heat sink" issue in that very specific place on the logic board. Surely this many people can't be having the same exact problems, in the same exact spot on the board and Apple not recognize it!??????
I did like your modification there, David, but hopefully we won't all have to do this when Apple comes to our rescue, right???? ha ha!

hi
i'd like to add my case to this topic too. Same story since last week, my G5 Dual 2Ghz won't start and testing changing trying like before discribed etc.

Now i found this topic and i tried the "Hair-dryer & push" method and look up IT WORKS! I agree, it seems that there is a Construction/Revision problem with this model.

sad........

thanks for the information, it helps understanding what happend

cheers

Thanks David for shedding the light on a very dim subject. My late 2004 G5 Dual 2.0 started overheating and into an 'emergency sleep' mode right in the heat of a battle in UT4. (Pun intended)
That probably contributed to the degradation of the logic board in the 'Sweet Spot' area that you identified. I am writing this on my new MacBook Pro as I look up at the 37" monitor that my G5 is filling with beautiful color again! I am running Hardware Monitor and watching the Cpu temps closely. Before my G5 completely died I had been noticing CPU B core reading -6.3 F (-21.3C) ! I figured the sensor was going bad. When I started up this evening CPU B read a normal 114 - 130 F (45-55C)
I burned a new Tiger install DVD to replace my original and about half way through CPU B again reads -6.3F. The G5 is still running but I have a feeling not for long. Anyone know where the core sensors are located? I am sure it has to do with the logic board failing because of the thermal expansion/contraction fatigue that is plaguing these otherwise fantastic machines.
I still have my first Apple, a IIe I purchased in 1982 for about the same price I paid for the G5. The only difference is the IIe still works! I have many Apple products that have stood up to lots of use and abuse. My QuickTake 100 took a dip in the San Lorenzo river (my wife saved my son from being washed down the rapids when he slipped and fell in!) I saved the QuickTake later that day with a hair dryer and some careful cleaning. Still works! Anyway the point being you are supposed to get what you pay for and the G5 issue makes me feel used. Come on Apple, we are die hard customers... for now.

Rokslyd

i tried this pressing method first..it started up ok but it got real hot real quicky. I waited an hour and tried the hair drier method and that worked for 3 consecutive start ups!

on the third restart, i decided to do a hardware test. It got about 2/3rds through and it froze, fans a-blazin'. force shut down and when i turned it back on, the spot i had pressed earlier was FIRE HOT!

as of right now, the computer is still flashing 3 times, im going to try the hair drier method again and see where that gets me.

<Edited by Moderator>

Message was edited by: wrbmonster

edited the link huh? - so much for free speech on the apple discussion forums

well anyways a friend of mine (who's much smarter in the computer hardware world) has said this to me:

"That's bizarre. Sounds like chip-creep. Over time, heating and cooling causes soldier points to crack or shrink away from the contact points. If it does this at a RAM socket, CPU can't see the RAM, so no boot. Heating it up probably caused the soldier to expand and temporarily touch the contacts again."

he brings up a very good point.

Message was edited by: wrbmonster

Thermal expansion and contraction is a rather well-known
phenomena in many materials and in several fields. Metal
is famous for fatigue and other symptoms of temperature
stress; as I mentioned in an earlier post...

"The act of heating the logic board at the point where these RAM sockets are
soldered on, and have that work, means there are micro-fractures or a faulty
solder joint at the junction..." {Heat expands metal, cold metal contracts.}

There are more than a few companies who can do the repair
work on the logic-board, and do such work on portable Macs;
so to contact one of those (reference Apple Discussions input)
to see what they say about the actual product, and if they have
experience in the issue or something similar; and are set up to
handle the logic boards of this larger computer device.

I don't have the link or name of one repeatedly cited electronics
repairer who can fix these kinds of circuits; so if someone else
finds it, perhaps the admin or moderator would allow a non-
active link (don't post http://www) for others to investigate further.

In any event, I know a friend across the continent who bought
one of these machines, used, that looks good and runs now;
and wonder when or if that machine will also develop this issue.

Good luck & happy computing! 🙂

Add me to the list! I started seeing weierdnes about 3 months ago....did some fiddling...and all was fine up until now. My studio gets very cold in the winter so I am almost certain that this has caused the solder fractures mentioned prior.

I too pushed on the mentioned "sweet spot" after hours of trying to diagnose why my G5 DP 2.0 would not boot up...and viola! However, after the computer booted into the OS I received a kernel panic and now the computer is back to the 3 LED flash.

Anyone know what kind of logic board I would need to purchase and where I can find directions on how to do so? I saw a possible $40 logic board replacement mentioned above via Ebay??

K,

That's a very informative response, thank you. Do you think that might also have something to do with a machine that refuses to restart until much later after it's been turned off? Sort of an "inverse" kind of thing? Sorry to intrude on the thread; I was here, the question was in my mind, your post gave me something to seize on and I couldn't let the moment slip away. Apologies to the OP.

No, it has nothing to do with how long I wait until I turn it back on again. I just tried booting again after pushing on the "sweet spot" and it booted up again but hit a kernel panic at the apple logo screen....UG. This computer is the center of my business and I am doomed without it.

If someone could please recommend the correct logic board and installation technique as soon as possible it would be much appreciated.

No it has nothing to do with how long I take until I try and restart. Once again I pushed on the "sweet spot" and was able to get the computer to the gray Apple logo screen when a kernel panic hit.

This computer is the core of my business and without it..well I am screwed. If someone could please get me the logic board info and directions on installing it I would be much appreciated!!

Dave,

K Shaffer's observations may apply to you as well but there could be many other causes too, a lot of them. Flashing LEDs point to RAM but that's a topic all by itself. Did you put in more RAM before things started acting up? Have you taken your RAM out, blown out any dust in the slots and area, put it back in, maybe just pairs at a time, and tried again to run? Did anything new precede the trouble? Have you run any maintenance programs like Disk Utility, or better yet DiskWarrior? Have you used Apple Hardware Test that came on the discs with your machine originally?

Here are two places I know off the top of my head for used Mac Parts, I've used both.
http://www.mac-pro.com/
http://www.dvwarehouse.com/Apple-Parts-c-3987_238.html

Here is a place to find out more about your Mac.

Going through your possible options:

"Did you put in more RAM before things started acting up?"

No...have had the same RAM in there for about 3 years.

"Have you taken your RAM out, blown out any dust in the slots and area, put it back in, maybe just pairs at a time, and tried again to run?"

Yes. Tried in different pairs and configurations to no avail...very random results.

"Did anything new precede the trouble?"

No other than I had not turned the computer on in about 8 days. it was a cold start the night the incident took place. As I said my studio does get cold so I thought perhaps that had something to do with the issue.

"Have you run any maintenance programs like Disk Utility, or better yet DiskWarrior? Have you used Apple Hardware Test that came on the discs with your machine originally?"

I cannot even get the computer to chime so getting to the point where can run any sort of disk repair utility is impossible.

I pressed on the sweet spot again and of course the computer started up and got as far as 4 minutes into running the operating system before a kernel panic hit.

Thank you for your info!

Can you start up from your system disc? (Command-C ) Tried booting into safe mode? (hold down Shift key). Reset Nvram? (Command-Option-O-F, and type, reset-nvram- Press Return-type, reset-all)