I recently upgraded the RAM and a hard drive on an old 2012 iMac. While this process generally went well I must have committed a fatal flaw at some point that ruined the iMac’s ability to use WiFi.
Although it appears nothing can salvage the WiFi I thought this was a meaningful exercise overall. The RAM upgrade worked, the hard drive upgrade worked, and I was able to buy a compatible USB WiFi card replacement. Still a bummer though. My working theory is I somehow accidentally damaged a very specific lead or connection on the mainboard that is critical for WiFi. No idea how, but I have no other explanation.
After upgrading the RAM and booting to macOS I saw that the wireless card was not detected. Interestingly, Bluetooth worked, but no hardware was detected at all for WiFi.
The hardware report listed no wireless cards of any sort. The wireless card was not touched during the RAM upgrade aside from disconnecting (and later reconnecting) the antenna cables as prescribed.
- Downgrading the RAM to the original OEM installed sticks
- Buying and installing another replacement Airport/Bluetooth board from iFixit
- Re-installing macOS
- Downgrading to the original macOS that came with this iMac (OS X Mountain Lion)
- Resetting the SMC and PRAM
Booting to a Linux distro to see if it could detect any wireless
hardware (no wireless devices from
+to see if I could add any wireless NICs (none available)
- memtest86+ memory diagnostics/tests (no issues)
Nothing seems to explain the WiFi failure, which is disappointing.
I do find it very odd that the Bluetooth on both Airport cards works fine, but WiFi fails for both.
I’m assuming something hardware related must have gone wrong during the upgrade. Maybe I didn’t exercise proper anti-static precautions or accidentally scraped a critical path on the mainboard with a tool I was using. Or perhaps the iMac already had an issue prior to this hardware upgrade that I simply overlooked.
Good reminder to exercise caution and better evaluate the state of things before, during, and after hardware work.