Mac Classic

Recently I wanted to reapply thermal paste to the CPU on my Power Mac G4 Quicksilver. This is a relatively simple task and only involves removing the CPU fan and heat sink. Before doing this I unplugged the machine and made sure I was wearing an anti-static wrist strap to prevent any electrostatic discharge (ESD) damage. I reapplied a small amount of thermal paste, put everything back together and powered on the computer. It turned on but there was no boot chime and nothing displayed on the screen. The power LED indicator faded off as soon as it was powered on, then it briefly lit up again if I pressed the power button.

I removed all devices from the computer (video cards, drives etc.) and it still wouldn't boot. I removed all of the RAM and turned the computer on again expecting to hear the beeping tone indicating no memory present/RAM issues. I didn't hear this which led me to believe there was an issue with the CPU since the machine wasn't making it to the boot diagnostics.

I installed a replacement logic board into the Quicksilver and got the same results which narrowed it down to the CPU even more. After removing the CPU and closely inspecting it I noticed a tiny amount of discoloration on several of the CPU pins. It looked like they had oxidised slightly which was strange considering it wouldn't have been removed since the machine was bought. Next I got a toothbrush and very carefully brushed the affected pins. I couldn't remove all of it but I thought I'd put the CPU back to see if it made a difference.

After reinstalling the CPU the Quicksilver chimed and booted as normal! For now it's working fine but I need to find a way of removing the oxidisation without damaging the CPU.

Barely noticeable, at a quick glance the pins look fine.

Barely noticeable, at a quick glance the pins look fine.

Upon closer inspection there is a small amount of green oxidisation on several pins.

Upon closer inspection there is a small amount of green oxidisation on several pins.

Comments

Bolkonskij

09 July 2022

Wow, that's a nasty surprise. And one I frankly haven't heard before. I thought the connectors fit well into the CPU. It's odd how oxidation could occur on that spot, though it's visible from the photos. Is the room the Quicksilver lives in rather humid?

Greystash - Admin

09 July 2022

It is very strange! When the CPU is connected it's a tight fit and I don't understand how those pins could have become more exposed than the rest of the machine. I couldn't see evidence elsewhere so maybe dirt or grime got in when it was originally installed.

Humidity may have contributed to this, the climate here is cold but it's a reasonably dry house. Hopefully it holds out until I can find a backup/replacement

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