Q: G5 startup light flashes 3 times then after a pause flashes 3 times etc.

I just recently reflowed the U3 memory controller chip 0n a 2.5 GHz with a heat gun and some solder flux, took three tries but I think I got it finally.

That's great, you should do a write up, maybe post it in...

http://x704.net/bbs/

I may, it seems so on the ragged edge of scraping it when I did it, the U3 chip is a big giant BGA which has two types of solder, the balls melt at a higher temp and the paste melts at a lower temp, so you have to bring it to the highest temp before the balls melt, if they do your finished.
Also you have to make a heat shield for the chips heat-sink so you wont overcook the chip itself, ( I used stainless steel foil ).
I found it best to leave the logic board stiffener (the metal plate) on when doing the reflow, because without it the circuit board warps tremendously and causes the whole job to fail, and I don't have the ability to heat the entire logic board.

I also re-soldered an entire memory slot and numerous thru board connections on this logic board so it may have been any or all, cant say for sure.

I have another dual 2.5 GHz AquaMac I may try to fix, if I have success I will post for sure, I hate to see this problem so common in the PM G5 its almost the Xbox 360 of the apple line, I find this same problem in about half of all G5's, It's so common that when I see these symptoms, I can almost always get one to boot by pressing on the inside edge of the serial number sticker of the logic board and or warming the area while powering up.

This is the first time I have been successful with this (I may have just got lucky), and Im still stress testing the repair via power cycling the unit, Im using it to type this for instance and then it will be shut down and so on.

I'll be back...

Message was edited by: G4ever

Nice, I'll be looking forward to hearing the outcome!

Well so far so good, this one hasn't given any problems, like I said I may have just gotten lucky.

My second $20 basket case is being a bit more of a problem.

All I get with it is the power light wont turn on but everything seems to power up, no chime, no video.

And I have another Logic Board that seems fine except that the coolant pump just runs flat out on full all the time, not sure where to look on that one..

I'll just have keep trying, my processors on this one may be bad, and I dont want to start tearing the running one apart again.

I sure would like to know why this logic board runs the pump on high all the time. (fails the test on ASD)

I sure would like to know why this logic board runs the pump on high all the time. (fails the test on ASD)

My guess would be the Failsafe, if the sensor/controller can't be addressed then it runs full speed, just like the Fans do.

This discussion might have info of interest:
http://discussions.info.apple.com/thread.jspa?threadID=1940728&start=135&tstart= 0

Found it! Q-60 and D-41 were the culprits, must have been shorted at one time before my possession, swapped them from a parts board, pump now passes ASD test.

Great work, thanks for the report!

May I say a very big thank you who would of thought that my daughters "Groovy Chick"
hair dryer would save a G5....And me a shed full of cash

Hi-

Welcome to Discussions!
Reality is stranger than fiction, isn't it!?

Great news, good work, thanks!

Hello,
I am having the same problem. G5 won' boot, black screen, no chimes, if left, the fans will race. At first I thought my HD crashed. Unpacked my books, and found the 3 flash section in the Mac guide book. I had using canned air three weeks ago to clean out dust from the inside and everything was working fine till four days ago.

I tried pulling the RAM and re-inserting.
I will try the hair dryer trick.

I have a few more problems. Was planning to install a new optical drive, found out I had to upgrade from Panther to support that and a new external drive to copy a bootable clone of my HD onto. Ok so far, got the Leopard 10.5 upgrade, was checking out optical drives and a bootable external HD, then the black screen and three flashes happened.

I thought my HD crashed, so I went to the Apple Store nearby and they wanted to sell me a 1TB HD for $99. I went to Staples and got the same thing for $79.
I did not install yet.

Upon reading further into the G5 tech specs I saw that my machine has two serial ATA controllers supporting up to 150-MBps and two HD bays. In addition, I read that the capacity for the Serial ATA drives is 500GB max system capacity.

So this means a 1 TB will not work in my machine. I called the Apple store and they said I probably cant buy a HD smaller than 500 these days.
So I can't buy two 250GB and replace my old one of five years,(which I was planning to do) Really? Then I read further on down in these posts that a user should consider buying a new mac instead of trying to upgrade the older G5.
I am bummed to hear that cause mine cost $3700 with the monitor.

My questions are: Can I upgrade this machine myself?

Should I just replace the RAM cards or switch them around to see if one is the culprit. I can put up to 8GB on this model. What if it is the slot the card goes in? Is that called the DIMM? Can they be replaced if I do this myself? I am aghast at thinking I would have to junk the G5. I know of PC's that are way older than mine that are still chugging along.

The store said they really couldn't help me over the phone ( of course) without seeing the machine, since its an older model.

I really do not want to get a new computer after having paid so much for this machine.

I am using the public library to access this forum so it may be a few days before I get back.

If someone needs more spec information on this machine, let me know.

Many thanks,

Loretta

Hi Loretta,

I read that the capacity for the Serial ATA drives is 500GB max system capacity.

That's because that was the biggest available at the time, a G5 will handle a 1 GB, & most a 2 TB drive.

Can I upgrade this machine myself?

Yes, but we don't know what's wrong with yours yet.

What exact model of HD did you get, some need a jumper on pins 5 & 6 to limit it to SATA 1 & II speeds.