Apple iMac G5 repair session

September 13th, 2012 @ // No Comments

We have just completed a comprehensive repair of an old iMac G5. Here is a short list of the problems it had.

– could not start every time
– when it starts it usually crashes couple of minutes later

and some problems we have discovered later

– SuperDrive is not working. Since no boot from USB is available this is a major issue if you don’t have a spare one.
– Airport disappeared
– software errors regarding boot process

The symptoms lead us to thinking what the problem turned out to be. Faulty capacitors on the motherboard, also known as “capacitor plague”. Poor quality, aging and high temperatures lead to catastrophic failure of the capacitors thus preventing them from adequately filtering the direct current voltages on the motherboard resulting in system instability. Visual symptoms like cracks on top with electrolyte spillage over them can be spotted.

Some symptoms:

The problem with this is that there are more then 25 capacitors all over the iMac G5 motherboard …and you have to change all of them to do the job properly. You need nerves of steel, steady hands, nice docking station and soldering equipment. Otherwise you can damage the motherboard, which is made from several different layers. This is why in many places you get the whole motherboard changed, which is expensive and not justified on old Macs because of its price.

So couple of hours and 29 capacitors later …. on a board not meant to be repaired

Voila …. we have lift off …. but as you have probably guessed we are far from over…. a PRAM reset is needed because of the massive dissemblance and the removal of all power sources and batteries …. it would also probably solve the boot problem it had (they were different from the capacitor plague issues).

We have successfully loaded the ages ago installed MAC OS Tiger

Can you spot the antics in the distance? We at just love history.

Anyway back to reality. We have added some memory to the G5 and decided to put the newest operating system it can handle, 10.5.8 Leopard.

Some of problems associated with that…

– the SuperDrive is not working, as on almost every old Mac …. and even if it was working …it was a single layer drive opposed to the Tiger’s double layer installation DVD.
– this old Mac does not have the “boot from USB” option….

There are couple of solutions to install the OS …. new drive being the easiest one.
If you don’t have one, here is a tip for free …. you can use standard non SATA slim DVD that support double layer. You will need to remove its front plastic cover bar and will have to lock the disk inside forced by the Mac’s chassis since the drive is not slot loading type. This solution seems a little bit extreme but it will do the job for the instillation, which is pretty straight forward.

So after a lot of work we have some progress. Finally.

By coincident after installing the new OS, the Airport disappeared. This is a common issue. It might be software or hardware issue. Since it is a full OS install and not an upgrade we had to check for mechanical failure at first. And it was indeed a hardware issue. Although not removed from the motherboard during the repair the huge dissemblance of everything around it may have resulted in loss of contact with the motherboard. Due to poor design, the socket mechanism of the wireless adapter is prone to poor contact, so be careful.

The fixed machine is fully stress tested and working for over a month now. And we are very proud of it.

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