iMac G5 20" Mid 2005 (Maybe)

MacGuyFrom1831 said:

So you're saying that I need to buy a 100 or 130 watt solder iron? My current one is 48 watt and blasts out 450c.

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No, I'm not saying that, an iron of that range would probably be too large.

The tip needs to be clean and the right shape, as well as the correct temperature.

Maybe try adding some flux, and it may flow better when desoldering.

If need be, do some googling on tips and techniques if you need and check to have the correct soldering iron:
https://www.instructables.com/id/How-to-Pick-the-Best-Soldering-Iron/

PS: If you have a set of small jewelers screwdrivers, You can often use the smaller blade ones as a drill, and use them to drill through the remaining solder.

Just a thought... as you said you didn't have the proper size drills. But the set of small hand operated thumb twist drills is not that expensive usually.





- Patrick
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I still have to ask how you removed the caps. Normally one would heat them from the bottom, where the solder is and then when it is melted, pull that leg of the cap out by tilting the cap a little, then heat the other leg, pull it out and then dispose of the cap. Then you go back and clean up the solder pads with a wick or vacuum sucker. The body of the cap provides the grip and leverage to pull the legs out. When you are done, the board should look almost like nothing had ever been there.

And like Patrick, I still see a LOT of solder around the legs in the upper picture. With a good wick and a clean iron, almost all of the solder should have been pulled up from those pads. It's not a hotter iron, just melting is all you need, but the wick needs to be clean and the iron needs to be clean to get the heat on the solder.

Update

I was able to replace all the damaged capacitors and remove the old pins. I was having problems removing one last leg and I in my frustration damaged the hole One damaged hole with a wide hole and one hole stuck with a pin leg in it. However, there was a spare hole where I just placed the new capacitor in. Boots up, Apple logo, startup sound.... But, the screen still flickers and it freezes during boot up. I checked the motherboard service LEDS and all of them lights up (all 3, not the 4th one).

I am starting to think it is the powersupply or the graphics card. Most likely the PSU and I've read that you can use an ATX PSU on it? Has anyone tried one? Which model works? It works better than ever as in it is so smooth now and so silent... I also took a long time to clean it up properly

Well now I'm trying to look into the PSU as I suspect it being defect. I've opened it and apart from being filthy and nasty it does look alright. What are your thoughts on it?

I've just cleaned and refurbished the PSU. The iMac loads perfectly in Safe Mode. So the problem is the GPU! I now need to reflow or reball the GPU properly. This is the next step!

Well praise the LORD!!! It is working flawlessly!

Well done!

MacGuyFrom1831 said:

Well praise the LORD!!! It is working flawlessly!

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Good going! Thanks for sharing. Again way to go.

Well praise the LORD!!! It is working flawlessly!

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Congratulations and Well done. And welcome to the World of restoration!!!



- Patrick
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UPDATE

Just did a fresh install of OSX Leopard and upgraded the machine to 2 GB of RAM. Running flawless! Tiger was faster, but Leopard works better with newer hardware. I shall install a SSD in it as well and do a carbon copy of the HD, which it uses now to the SSD

Now I'm browsing the internet with the iMac G5 and it is working perfectly! I'm also updating the OSX with Apple updates from 2011! Monitor Applications are running greatly as well

Starting on the newer iMac

I've dissembled the newer iMac and to my undesirable surprise someone had opened it prior to me. Fixing something someone else messed up is never fun, but fixing things only touched by the factory is always preferable. This is not the worst issue at this stage. I dissembled the whole unit and took off the motherboard. From my inspection it looked like that I had to exchange 9 capacitors, which were located at some troublesome locations. I took the heatsink off and could see huge amount of excessive thermal paste! Like crazy amount! The backplate was more or less covered in thermal paste! This could not be a factory job (I certainly hope not!)! The CPU was covered in paste and even had some burnt spots on it (maybe from the heat of the paste?). First, I tried to remove and clean the CPU with the plastic protectives on (bad idea), then I took it off and cleaned the areas and it looked like there was a missing pin or connect on a pin. It is placed on the CPU top and is very small and had to inspect – even with a microscope. I tried my best to inspect it and I am very unsure. However, it does seem like there is contact and I really hope this will not make problems later on and resulting in the machine not working.


I have enclosed pictures from my progress. Let me know what you guys think. Thanks for listening and your feedback ?

Picture limit from prior post.

The problem on the CPU is on the write area.... Chip number 2 from the bottom to the left.... Pin number 1 (maybe 2) from the top from the right. I don't know if it has enough contact. Any thoughts?

Any thoughts?

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Good luck.

I'm too old to get into such Mac repairs these days and any such enthusiasm I used to have waned many years ago.

It definitely looks like you may be be fixing a fix. Not the best situation at all.

PS: There was a period many years ago where the factory applied thermal paste had been applied as thought was done by a five-year-old, and just smeared all over the place. I can't remember what years or period that was. But it might have been close to the bad caps era.

https://en.wikipedia.org/wiki/Capacitor_plague

That G5 is probably from that era as you no doubt know.

At least caps are usually cheap enough and made better these days.



- Patrick
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Hi Patrick,

here you have two pictures from the opposite angle of the small chip on the CPU. Number 2 from the right and the bottom pin all the way to the left. Is there enough contact on the pin? What are your thoughts (and the rest) on this please?

What are your thoughts (and the rest) on this please?

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Sorry MacGuy, I just don't have the necessary experience to advise you correctly.


- Patrick
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pm-r said:

Sorry MacGuy, I just don't have the necessary experience to advise you correctly.


- Patrick
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No problem and thank you for being honest. I've tried to look at it again, but the chip and legs are so small I need some professional magnifyer to be sure. But, I hope and think there is contact

Looks like you have quite a few swollen caps to replace. And whoever did that thermal paste job obviously didn't know what they were doing. And no, it didn't come that way from the factory.