Chosen Solution
I have a bluetooth problem on my iMac 2010 27”. Tried SMC, PRAM and even replaced the whole Bluetooth card, antenna and cable. Reinstalled MacOS high Sierra (erased and then fresh install), also tried removing the plist files. Under Bluetooth explorer, I get the following in event log when I try to open Bluetooth set up assistant. Anyone seen this and been able to resolve it? Process: Bluetooth Explorer 4.4.0 Operating System: Version 10.13.6 (Build 17G66) Date: 2021-01-03 14:06:08 +0000 Initializing Bluetooth… Bluetooth Support Initialization complete. updateChainPower error: -3900 2021-01-03 14:06:49 +0000 Apple80211Get(APPLE80211_IOC_BTCOEX_MODE) returned error -3903 updateChainPower error: -3900 Jan 3 14:12:24 imacs-iMac com.apple.xpc.launchd[1] (com.apple.xpc.launchd.domain.user.501): Service “com.apple.xpc.launchd.oneshot.0x10000003.Bluetooth Setup Assistant” tried to register for endpoint “com.apple.btsa” already registered by owner: com.apple.btsa Jan 3 14:12:24 imacs-iMac com.apple.xpc.launchd[1] (com.apple.updateEFIDesktopPicture-apfs[536]): Service exited with abnormal code: 1
Sounds like the feed to the Bluetooth board from the logic board is having issues! I would first trace out the continuity of the cable from the logic board connector to the BT board connector to make sure its not a simple connection issue.
If you’ve already done that then that starts to get into repairing the logic board. So here’s a snippet of the area we are working on. I would check external USB Ports to see if they are working as that could offer a clue if the issue is the hub chip or the feed to it.
And here’s the full breakdown of the logic
You’ll need to probe the voltages to see what failed
