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Thanks, Droid. My iMac is currently at the Genius Bar and not in my possession. I was trying to weigh whether to go get it and try this on my own or let them do it. It has been there for quite awhile now because Apple issued extended repair programs on both the power supply AND the logic board, the same two problems I've had, on machines with model numbers that ended immediately before mine. I figured by now they would've issued the same for this model number but it looks like they're expending all their energy on damage control instead.
Power Mac G5 logic board failure?
MultiQuote
#478
Droid 
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Posted 03 March 2009 - 08:41 PM
As promised a few weeks ago (sorry for the delay) I have added the data from the dead mac list to my Google docs. Basically this means you can have a look at the data in a convenient format.
More info here
I'll manually add new machines as they get added.
More info here
I'll manually add new machines as they get added.
#479
timporary
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Posted 07 March 2009 - 08:41 PM
Droid,
First of all, I'm nearly technically illiterate. If I hadn't already decided I'd either get the board fixed or buy a new machine, I'd never have touched the thing. But, that being said, I have the logic board off of my G5 and can see what looks like 5 layers where the heat sink is (listed board side first):
1. A white square piece connected by pins to the board.
2. A smaller piece centered over the white layer.
3. Another large white layer.
4. Some green adhesive(?) Very goopy and loose.
5. The silver (in mine) heat sink.
Heat Sink Assembly 1
Heat Sink Assembly 2
Heat Sink Assembly 3
The green layer is only spread 1/2way across the space between the heat sink and the white layer. My questions are these: Could that cause the blank screen and lead to the subsequent hair dryer fix? And, what, exactly, is the green stuff and could I add more to see if it will solve the issue?
In another note, one of the springs on the black heat sink pegs was stuck in a squished position and I re-sprung it. Don't know if that will effect anything, bt I thought I'd mention it.
Thanks for your time.
First of all, I'm nearly technically illiterate. If I hadn't already decided I'd either get the board fixed or buy a new machine, I'd never have touched the thing. But, that being said, I have the logic board off of my G5 and can see what looks like 5 layers where the heat sink is (listed board side first):
1. A white square piece connected by pins to the board.
2. A smaller piece centered over the white layer.
3. Another large white layer.
4. Some green adhesive(?) Very goopy and loose.
5. The silver (in mine) heat sink.
Heat Sink Assembly 1
Heat Sink Assembly 2
Heat Sink Assembly 3
The green layer is only spread 1/2way across the space between the heat sink and the white layer. My questions are these: Could that cause the blank screen and lead to the subsequent hair dryer fix? And, what, exactly, is the green stuff and could I add more to see if it will solve the issue?
In another note, one of the springs on the black heat sink pegs was stuck in a squished position and I re-sprung it. Don't know if that will effect anything, bt I thought I'd mention it.
Thanks for your time.
#480
Droid
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Posted 08 March 2009 - 07:21 AM
I'm not sure what can be achieved by getting this heat sink off. It has over a thousand tiny connections that are impractical to repair without the proper kit. I don't know if reseating the heat sink will do much beyond making you feel like you have done something to try to fix it :) I'm planning on getting mine reballed I'll post when I have got it back together afterwards. The various youtube reballing videos don't give me enough confidence to try on this chip.
Nice job, I hope you got the SS manual.
That is the chip, the pins are actually made from tiny solder balls.
That is still the chip, I think it is the main silicon part (the bit that gets hottest). It is small compared to the rest of the chip.
I think you are referring to the aluminum part of the chip. There is a thick sheet of aluminum attached to the chip, it needs to stay attached as far as I can tell. I think it only contacts the silicon layer on the chip to draw away the heat towards the larger heat sink.
These (poor quality pics) may help clarify
pixelchimp.net/g5-board/g5-6.jpg
pixelchimp.net/g5-board/g5-7.jpg
I suspect it is grey, but dusty. This is the bit that separates from the chip. If I'm understanding you correctly, then this is the thermal compound that connects the heat sink.
5. The silver (in mine) heat sink.
You seem to have the same style heat sink as in the services source manual (p.145). The big silvery bit with the sprung pins and the cooling pipes is what comes off. Mine was very firmly stuck to the chip, the thermal compound Apple used had dried and stuck very well to the sink. You need to be very careful if you remove this because the heat sink pipes are very soft & flexible, they bend easily. Before you start you need to remove the sprung pins from the pcb board. They need to be gently squeezed from the other side of the board and poked through. There are some other pins that hold the 'pipes' in place too.
The green layer is only spread 1/2way across the space between the heat sink and the white layer. My questions are these: Could that cause the blank screen and lead to the subsequent hair dryer fix? And, what, exactly, is the green stuff and could I add more to see if it will solve the issue?
I'm sorry I can't answer that, I just don't know. The hairdryer fix that I read about was mentioning heating in this area of the board. It would make sense that heating this particular chip could cause any cracked joints to push back together enough to make a connection, but it's merely speculation, I have no evidence this is actually what is happening.
The main area of concern on this particular chip is the ball grid array (BGA), they look like pins, but they are made up of tiny balls of lead solder that are fixed to the board & chip buy a slightly different mix of solder that melts at a lower temperature.
The heat sink is forced into contact of the chip by the little springs on the pins, it keeps pressure on the chip & the ball grid array. I think over time the heating and cooling of the BGA causes it to collapse under the pressure. You can see this in the IBM PDF's mentioned earlier in this thread. It could be that any collapsed balls are shorting out. This chip is the U3 controller, it bridges between the CPU's and memory & other systems as far as I can tell.
I think the green goopy stuff is thermal compound, you can buy it from PC hardware stores. It comes in several types, it can be replaced. You need some isopropyl alcohol to clean the chip & the sink, then let that dry & reapply a thin layer of fresh compound to the chip. Too much is as bad as not enough, so do a little google research.
In another note, one of the springs on the black heat sink pegs was stuck in a squished position and I re-sprung it. Don't know if that will effect anything, bt I thought I'd mention it.
Thats interesting, it could mean less pressure was applied to one side of the chip, or it could have been dislodged when you removed it from the case.
Thanks for your time.
No problem, I hope you manage get it back together :^) .
timporary said:
Droid,
First of all, I'm nearly technically illiterate. If I hadn't already decided I'd either get the board fixed or buy a new machine, I'd never have touched the thing. But, that being said, I have the logic board off of my G5 and can see what looks like 5 layers where the heat sink is (listed board side first):
First of all, I'm nearly technically illiterate. If I hadn't already decided I'd either get the board fixed or buy a new machine, I'd never have touched the thing. But, that being said, I have the logic board off of my G5 and can see what looks like 5 layers where the heat sink is (listed board side first):
Nice job, I hope you got the SS manual.
Quote
1. A white square piece connected by pins to the board.
That is the chip, the pins are actually made from tiny solder balls.
Quote
2. A smaller piece centered over the white layer.
That is still the chip, I think it is the main silicon part (the bit that gets hottest). It is small compared to the rest of the chip.
Quote
3. Another large white layer.
I think you are referring to the aluminum part of the chip. There is a thick sheet of aluminum attached to the chip, it needs to stay attached as far as I can tell. I think it only contacts the silicon layer on the chip to draw away the heat towards the larger heat sink.
These (poor quality pics) may help clarify
pixelchimp.net/g5-board/g5-6.jpg
pixelchimp.net/g5-board/g5-7.jpg
Quote
4. Some green adhesive(?) Very goopy and loose.
I suspect it is grey, but dusty. This is the bit that separates from the chip. If I'm understanding you correctly, then this is the thermal compound that connects the heat sink.
5. The silver (in mine) heat sink.
You seem to have the same style heat sink as in the services source manual (p.145). The big silvery bit with the sprung pins and the cooling pipes is what comes off. Mine was very firmly stuck to the chip, the thermal compound Apple used had dried and stuck very well to the sink. You need to be very careful if you remove this because the heat sink pipes are very soft & flexible, they bend easily. Before you start you need to remove the sprung pins from the pcb board. They need to be gently squeezed from the other side of the board and poked through. There are some other pins that hold the 'pipes' in place too.
The green layer is only spread 1/2way across the space between the heat sink and the white layer. My questions are these: Could that cause the blank screen and lead to the subsequent hair dryer fix? And, what, exactly, is the green stuff and could I add more to see if it will solve the issue?
I'm sorry I can't answer that, I just don't know. The hairdryer fix that I read about was mentioning heating in this area of the board. It would make sense that heating this particular chip could cause any cracked joints to push back together enough to make a connection, but it's merely speculation, I have no evidence this is actually what is happening.
The main area of concern on this particular chip is the ball grid array (BGA), they look like pins, but they are made up of tiny balls of lead solder that are fixed to the board & chip buy a slightly different mix of solder that melts at a lower temperature.
The heat sink is forced into contact of the chip by the little springs on the pins, it keeps pressure on the chip & the ball grid array. I think over time the heating and cooling of the BGA causes it to collapse under the pressure. You can see this in the IBM PDF's mentioned earlier in this thread. It could be that any collapsed balls are shorting out. This chip is the U3 controller, it bridges between the CPU's and memory & other systems as far as I can tell.
I think the green goopy stuff is thermal compound, you can buy it from PC hardware stores. It comes in several types, it can be replaced. You need some isopropyl alcohol to clean the chip & the sink, then let that dry & reapply a thin layer of fresh compound to the chip. Too much is as bad as not enough, so do a little google research.
In another note, one of the springs on the black heat sink pegs was stuck in a squished position and I re-sprung it. Don't know if that will effect anything, bt I thought I'd mention it.
Thats interesting, it could mean less pressure was applied to one side of the chip, or it could have been dislodged when you removed it from the case.
Thanks for your time.
No problem, I hope you manage get it back together :^) .
#481
experiment1776
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Posted 08 March 2009 - 07:26 AM
Replying to myself. I noticed that this is still a hot topic 450+ posts later!!!! I originally posted #11 in Aug last year. Since then I have had a flawlessly running G5. Of course I went over a month without it and it took two attempts. Hopefully I can get another couple years. Still, it is disconcerting b/c we all bought our computers so we would have at least 5 years of headache free computing. Keep making your voices heard, apple would be stupid not to listen.
#482
Droid
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Posted 08 March 2009 - 07:44 AM
experiment1776 said:
Replying to myself. I noticed that this is still a hot topic 450+ posts later!!!!
If only you had a dollar for every post :)
It's good to now a repair can fix it provided you get a good logic board installed, it seems a bit hit & miss with this issue. I have a sneaking suspicion that it is really several different problems.
#483
timporary
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Posted 08 March 2009 - 08:56 AM
First of all, thanks again.
Secondly, are you 90% convinced that the reballing will take care of your problem? 80%? I was going to try First Phase Tech. and see what they could do with it. If it's worth the attempt, I'll do it, because my other option is to buy a whole new machine or spend the $1000 to repair a g5 that, from what I've heard, won't be supported by the next OS.
And, yeah, I don't feel at all comfortable taking the sink off, so I'll leave that on.
In the meantime, is there an easy way to disconnect the shelf that runs across the logic board? I know about the 3 screws in the back, but I'm not sure which if the wiring if any that runs through the structure is okay to take off, especially considering that I need to put it all back together at some point. I'm wondering if it might be easier just to ship it off attached, or if that'll make everything harder on everybody.
Oh, one last thing. The pins aren't actually touching anything as far as I can tell. They're connected to the aluminum, but seem to float while poking slightly into a hole on the board. So, I guess the aluminum is just supposed to press against the chip because of the adhesion of the thermal compound? I've read threads about mac laptops with the same (or similar) problem just needing a shim tha forced the chip/sink down (if I read the threads correctly) and it makes me wonder if that floating sink is the problem. I checked the case itself to see if there was somethign to press the chip down, but there's just a ghosted heat mark in the shape of the sink.
Secondly, are you 90% convinced that the reballing will take care of your problem? 80%? I was going to try First Phase Tech. and see what they could do with it. If it's worth the attempt, I'll do it, because my other option is to buy a whole new machine or spend the $1000 to repair a g5 that, from what I've heard, won't be supported by the next OS.
And, yeah, I don't feel at all comfortable taking the sink off, so I'll leave that on.
In the meantime, is there an easy way to disconnect the shelf that runs across the logic board? I know about the 3 screws in the back, but I'm not sure which if the wiring if any that runs through the structure is okay to take off, especially considering that I need to put it all back together at some point. I'm wondering if it might be easier just to ship it off attached, or if that'll make everything harder on everybody.
Oh, one last thing. The pins aren't actually touching anything as far as I can tell. They're connected to the aluminum, but seem to float while poking slightly into a hole on the board. So, I guess the aluminum is just supposed to press against the chip because of the adhesion of the thermal compound? I've read threads about mac laptops with the same (or similar) problem just needing a shim tha forced the chip/sink down (if I read the threads correctly) and it makes me wonder if that floating sink is the problem. I checked the case itself to see if there was somethign to press the chip down, but there's just a ghosted heat mark in the shape of the sink.
#484
benjikant
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Posted 08 March 2009 - 09:09 AM
This is my second post. I am still running on only one of my two processors i.e. a dual processor 2.3 GHz G5. It just cacked out on me several months ago, yet still running on the one, albight a lot slower. Is Apple acknowledging this problem? After only three to four years, you would expect it to still run. I never had these problems with my Mac G4.
Any suggestions?
Thx
Ben
Any suggestions?
Thx
Ben
#485
Droid
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Posted 08 March 2009 - 10:17 AM
timporary said:
First of all, thanks again.
Secondly, are you 90% convinced that the reballing will take care of your problem? 80%? I was going to try First Phase Tech. and see what they could do with it. If it's worth the attempt, I'll do it, because my other option is to buy a whole new machine or spend the $1000 to repair a g5 that, from what I've heard, won't be supported by the next OS.
Secondly, are you 90% convinced that the reballing will take care of your problem? 80%? I was going to try First Phase Tech. and see what they could do with it. If it's worth the attempt, I'll do it, because my other option is to buy a whole new machine or spend the $1000 to repair a g5 that, from what I've heard, won't be supported by the next OS.
>
I'm probably about 60% sure! I have no way of testing to find out and there doesn't seem to be any UK companies that will test the board to find component failures - it would also be cheaper to get a new or reconditioned logic board. It's just a hunch really, but the cost #80 is something I think I can risk. There is another chip (U4) that is mounted in the curve of the 'heat pipe', Mine is an AMD chip, this could be suffering a similar issue, since it is a BGA chip that has the heat sink tensioned onto it.
pixelchimp.net/g5-board/g5-3.jpg
It is my gut feeling that the larger one with the major heat sink is the most likely to go. I think the U3 fits in with the booting on 2 CPU's when cold and 1 CPU when hot flakyness I experienced. The temp effects infer that expansion is opening up bad joints.
Quote
In the meantime, is there an easy way to disconnect the shelf that runs across the logic board? I know about the 3 screws in the back, but I'm not sure which if the wiring if any that runs through the structure is okay to take off, especially considering that I need to put it all back together at some point. I'm wondering if it might be easier just to ship it off attached, or if that'll make everything harder on everybody.
Removing it is easy, the fan socket disconnects from the board, and the cables slide out of the clips. Google 'Service source G5' it is worth its weight in gold. The tech's that do any repair will charge more to remove & refit the sink. I was told the board will need baking for a day to remove moisture before the removing begins, so whatever you can get off should help them. Take a lot of photos of cable routing before you remove it.
Quote
Oh, one last thing. The pins aren't actually touching anything as far as I can tell. They're connected to the aluminum, but seem to float while poking slightly into a hole on the board. So, I guess the aluminum is just supposed to press against the chip because of the adhesion of the thermal compound? I've read threads about mac laptops with the same (or similar) problem just needing a shim tha forced the chip/sink down (if I read the threads correctly) and it makes me wonder if that floating sink is the problem.
Do you mean the black plastic pegs with the springs, or the actual 'pins' (balls) on the chip?
There should be no gap between the balls & chip, but the pegs just apply the spring tension to the heat sink. The pegs can move to accommodate any movement on the chip. I'd expect that adding extra pressure via a shim could cause the BGA to breakdown eventually anyway. You could achieve the same effect, by using stronger springs but the IBM docs suggest they did enough research to get it 'just about right'.
Quote
I checked the case itself to see if there was somethign to press the chip down, but there's just a ghosted heat mark in the shape of the sink.
I have that same heat shadow on the inside of the case too.
Don't forget to look at all the components to see if there is any burned ones or expanded capacitors etc. I opened up the PSU to clean that & give it a look over, it could give you clues.
I plan to take my board in some time this week, I don't know if you want to wait until it's done, I don't have a firm date but it may stop you spending money if mine fails to do anything.
#486
Droid
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Posted 08 March 2009 - 10:37 AM
benjikant said:
This is my second post. I am still running on only one of my two processors i.e. a dual processor 2.3 GHz G5. It just cacked out on me several months ago, yet still running on the one, albight a lot slower. Is Apple acknowledging this problem?
Some people have managed to hassle Applecare or Customer Relations (1-800-767-2775) and get repairs or even a new Mac Pro. I think it is the luck of who you speak to, and if you have previous issues in the G5's history. I'm surprised you are still running on 1 CPU after a couple of months, my dual 2.3GHz didn't last long booting with only 1. My 2001 G4 Dual 450 is still working (had to replace the power supply unit).
#487
VladimerePain
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Posted 08 March 2009 - 09:23 PM
Thanks to the picture links that Droid posted; I found myself doing the proverbial "Doh" when I saw that there is an AMD processor inside these units. I do believe the problem has been located. LOL. The used power supply has the system running. Unfortunately shortly after the installation of the power supply the secondary processor went out. I purchased a pulled processor from eBay. It has the system up and running, but only on one processor. The system I have is early 2005 and shipped with the 970FX processors and the one I purchased was from mid 2003 and is one of the 970 processors and presumably of the primary class. I'll probably just see how long this lasts and end up getting a new Mac Mini when I can afford it. Maybe in about three to fours years if this machine is still running and the replacement parts are cheap I'll see about finding a replacement for the secondary processor.
Serial Number G85323FPRTY
Serial Number G85323FPRTY
#488
alvaro_dw
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Posted 18 March 2009 - 11:29 PM
Yep same story with me. I have a G5 2GHZ, bought it in early 2005. 4yrs later, wont boot up, gets stuck on grey apple screen, fans sound like jet engines, can't even boot up from disc. tried everything metioned in this thread nothing seems to work. I took it in the store and they told me it was a bad HD, replaced the HD and it only worked for 10min and it crashed again. I called apple and they told since they gave me the wrong advice at the apple store they were going to open a case for me and told me to take it back to the store and show them my case number, I guess I'll see how that goes.
#490
californiak
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Posted 22 March 2009 - 02:08 PM
Same here, G5, 1.8DP (june '04 edition), Tiger . I am working on it right now, got the whole thing out, power supply, logic board. Will eventually try reballing the logic board and will post detailed step by step process with pix.
However right now I am doing the power supply and need help, if anyone has hi-rez pix of back of the power supply board I would appreciate you let me know, the area I need to look at are the solder points where all the wires are attached - I need the back side photo to check what is supposed to be soldered where. It seams there are some areas I am not sure if they must cross over to next pin or not.
Better yet if anyone in Los Angeles area has power supply board that is out or spare that I could look at, even bad PS board would do, so I can compare the two. Old not functioning G5, 1.8 DP for sale?
If anyone in LA area wants to get together and compare notes I would like that also. Once I find out for sure that the problem is not the power supply I will move on to reballing/reflowing the logic board. If I can fix my logic board, I may set up website to guide some of you that need the same fix.
Email me with pix or comments at: morho1 at charter dot com or post here, I'll be monitoring this thread
Thanks, MG
However right now I am doing the power supply and need help, if anyone has hi-rez pix of back of the power supply board I would appreciate you let me know, the area I need to look at are the solder points where all the wires are attached - I need the back side photo to check what is supposed to be soldered where. It seams there are some areas I am not sure if they must cross over to next pin or not.
Better yet if anyone in Los Angeles area has power supply board that is out or spare that I could look at, even bad PS board would do, so I can compare the two. Old not functioning G5, 1.8 DP for sale?
If anyone in LA area wants to get together and compare notes I would like that also. Once I find out for sure that the problem is not the power supply I will move on to reballing/reflowing the logic board. If I can fix my logic board, I may set up website to guide some of you that need the same fix.
Email me with pix or comments at: morho1 at charter dot com or post here, I'll be monitoring this thread
Thanks, MG
