iMac powers down randomly (27” 2017)
My iMac continues to power down randomly, or my display goes dead/black. I must unplug the AC power cord, and wait several seconds or more before plugging back in - only then will it power back on. When I run the Hardware test, it always passes - code APC0000.
I brought it to my local (in Mexico) Authorized Mac Store before Christmas 2017. They kept it 3 weeks and eventually they replaced both the power supply and the main/logic board. Yet, the power down problem continues. (I bought my iMac in May 2017, but it's essentially got many new innards as of late Dec 2017). I brought it a second time to the local Mac Store, they reinstalled the OS (an older one than what I brought in, 10.13.0, I updated it to the latest when I got it home, 10.13.3). They had it a second 3 weeks and said it stayed on for 4 days - which I don’t belive. It still it powers down and has powered down every day, many times since I have had it back (one week).
Below I have pasted both an EtreCheck report and a Terminal "log show" listing for earlier crashing.
I reinstall the newest OS X (High Sierra). Since the problem existed with my older OS (one before High Sierra) and continues to happen with High Sierra and on this new supply & main board, this means to me that it is NOT A SOFTWARE (OS) PROBLEM. It is certainly a hardware problem. (Correct?) I think the new power supply installed in late December 2017 is either (1) fine and it is something else (2 supplies can’t easily exhibit the same problem); (2) defective (powers down randomly just like the older supply? Which seems unlikely), or (3) the new supply is not physically installed correctly (just like the old supply?). Maybe there is a failing, misplaced or missing heat sensor, AC or ground fault protection cable?
I am not certain if the ”hold down D” hardware test checks for bad heat sensors - my computer does not display an “extended HW test” option. I have tried both a local (D during power up) and an Internet (Option-D during power up) hardware test. Both show zero faults.
I have tried and tried many many times to reproduce the problem, but it is always random. Never consistent. It has powered off during rebooting (while the Apple logo & scroll bar still appears). It has powered down while Mail, or iTunes, or Disk Utility or Finder are in focus (or on top/active). It has even powered down when the screen is asleep (such as if I put it to Sleep and leave it over night - it is powered off in the morning). It has powered down in Safe Mode. It has powered down while it is cold (just turned on after being shut down and unplugged for AC power all night) and warm (after being in use for 10 minutes, or an hour…), so I am sure it is not a heat problem. I can never feel any warmth on the rear. Maybe a bad heat sensor that was not found when the new supply was installed?
When the power turns off, there is no warning. No message appears, No screen flicker, the screen goes black very quickly. The ONLY way to power the iMac ON again, is to unplug the AC power cord. The rear power switch does nothing until the AC power cord is unplugged, then eventually replugged. After I replug the AC power back in, the screen turns back on and the iMac powers back on. I never need to push the rear power switch. (I think this is because I have the Setting to "reboot after a power failure" turned on. This is the expected behavior.) However, once the problem happens, it is strange that the rear switch does not work. This perhaps suggests a power supply protection mode has been turned on?
I have the iMac 120 VAC power cable plugged directly into a professional SurgeX AC power device. This prevents the AC power voltage from exceeding 120 VAC. This product has auto over-voltage protection/turn off and the SurgeX has never tripped or shut down. I know this SurgeX product shuts down with overvoltages, because I tested it with an AC Variac This makes me VERY confident that the iMac power supply has not “seen” an AC over-voltage condition. However, perhaps the iMac is acting like it is experiencing an over-voltage condition? Perhaps the over voltage choke if failing? I think the iMac power supply has an input “clamp” circuit that protects the power supply in various ways? Perhaps this part of the iMac power supply is not working properly. But on two different power supplies? Maybe the supply was installed with a simple error, maybe the new supply is failing also?
I read online that a failing Terabyte hard drive may show a similar symptom. perhaps mt 3 TB drive is to blame?
ETRECHECK [I swap between two different Time Machines, one that has a complete backup, another that recently ran out of room, thus the "backup disk too small red flag - that I'm not worried about since I have a second newer complete Time Machine backup]:
EtreCheck version: 3.4.6 (460)
Report generated 2018-02-06 21:01:46
Download EtreCheck from https://etrecheck.com
Runtime: 1:37
Performance: Excellent
Click the [Lookup] links for more information from Apple Support Communities.
Click the [Details] links for more information about that line.
Problem: Other problem
Description:
iMac powers down randomly (or display goes black/dead?). I must unplug the power cord before it will restart.
iMac (Retina 5K, 27-inch, 2017)
[Technical Specifications] - [User Guide] - [Warranty & Service]
iMac - model: iMac18,3
1 4.2 GHz Intel Core i7 (i7-7700K) CPU: 4-core
16 GB RAM Upgradeable - [Instructions]
BANK 0/DIMM0
8 GB DDR4 2400 MHz ok
BANK 0/DIMM1
Empty
BANK 1/DIMM0
8 GB DDR4 2400 MHz ok
BANK 1/DIMM1
Empty
Handoff/Airdrop2: supported
Wireless: en1: 802.11 a/b/g/n/ac
iCloud Quota: 140.32 GB available
Radeon Pro 580 - VRAM: 8 GB
iMac 5120 x 2880
APPLE HDD ST3000DM001 disk0: (3 TB) (Rotational)
EFI (disk0s1 - MS-DOS FAT32) <not mounted> [EFI]: 210 MB
(disk0s2) <not mounted> [CoreStorage Container]: 3.00 TB
(disk0s3) <not mounted> [Recovery]: 650 MB
APPLE SSD SM0128L disk1: (121.33 GB) (Solid State - TRIM: Yes)
(disk1s1) <not mounted> [EFI]: 315 MB
(disk1s2) <not mounted> [CoreStorage Container]: 120.88 GB
(disk1s3) <not mounted> [Boot]: 134 MB
USB30Bus
Broadcom Corp. Bluetooth USB Host Controller
Apple Inc. FaceTime HD Camera (Built-in)
Logitech Trackball
USB31Bus
Apple Inc. thunderbolt_bus
Macintosh HD (disk2 - Journaled HFS+) / [Startup]: 3.11 TB (1.53 TB free)
Physical disk: disk1s2 120.88 GB Online
Physical disk: disk0s2 3.00 TB Online
macOS High Sierra 10.13.3 (17D47) - Time since boot: less than an hour
Mac App Store and identified developers
/Library/Extensions
[loaded] com.AmbrosiaSW.AudioSupport (4.1.4 - SDK 10.11) [Lookup]
/System/Library/Extensions
[not loaded] com.Belcarra.iokit.USBLAN_netpart (2.0.2) [Lookup]
[not loaded] com.Belcarra.iokit.USBLAN_usbpart (2.0.2) [Lookup]
[not loaded] com.RemoteControl.USBLAN.usbpart (2.0.6) [Lookup]
[not loaded] com.palm.ClassicNotSeizeDriver (3.2.1) [Lookup]
[not loaded] com.sounddevices.driver.USBPreAudio (4.0) [Lookup]
/System/Library/Extensions/Belcarra.USBLAN_netpart.kext/Contents/PlugIns
[not loaded] com.belcarra.iokit.netpart.panther (1.6.1) [Lookup]
/System/Library/Extensions/Belcarra.USBLAN_usbpart.kext/Contents/PlugIns
[not loaded] com.belcarra.iokit.usbpart.panther (1.6.1) [Lookup]
/System/Library/Extensions/RemoteControl.USBLAN_usbpart.kext/Contents/PlugIns
[not loaded] com.RemoteControl.USBLAN.panther (1.6.1) [Lookup]
[not loaded] 8 Apple tasks
[loaded] 173 Apple tasks
[running] 109 Apple tasks
[not loaded] 37 Apple tasks
[loaded] 181 Apple tasks
[running] 112 Apple tasks
[loaded] com.google.keystone.agent.plist (Google, Inc. - installed 2017-09-27) [Lookup]
[loaded] com.adobe.fpsaud.plist (Adobe Systems, Inc. - installed 2017-12-14) [Lookup]
[loaded] com.ambrosiasw.ambrosiaaudiosupporthelper.daemon.plist (Ambrosia Software, Inc. - installed 2016-09-03) [Lookup]
[loaded] com.google.keystone.daemon.plist (Google, Inc. - installed 2017-10-14) [Lookup]
[loaded] com.microsoft.autoupdate.helper.plist (Microsoft Corporation - installed 2017-04-28) [Lookup]
[loaded] com.rogueamoeba.instanton-agent.plist (Rogue Amoeba Software, LLC - installed 2017-08-14) [Lookup]
[loaded] com.apple.SafariBookmarksSyncer.plist (? ? ? - installed 2009-03-16)
[loaded] com.dropbox.DropboxMacUpdate.agent.plist (Dropbox, Inc. - installed 2017-08-11) [Lookup]
iTunesHelper Application (Apple, Inc. - installed 2018-01-24)
(/Applications/iTunes.app/Contents/MacOS/iTunesHelper.app)
Dropbox Application
(/Applications/Dropbox.app)
Audio Hijack 3 Schedule Helper Application
(/Library/Application Support/Audio Hijack/Audio Hijack 3 Schedule Helper.app)
FlashPlayer-10.6: 28.0.0.137 (installed 2018-01-10) [Lookup]
QuickTime Plugin: 7.7.3 (installed 2018-01-19)
Flash Player: 28.0.0.137 (installed 2018-01-10) Outdated! Update
iPhotoPhotocast: 7.0 (installed 2013-04-28)
JavaAppletPlugin: 15.0.1 (installed 2013-12-07) Check version
SharePointBrowserPlugin: 14.7.2 (installed 2017-03-14) [Lookup]
CitrixOnlineWebDeploymentPlugin: 1.0.105 (installed 2013-04-25) [Lookup]
WebEx64: 1.0 (installed 2016-04-07) [Lookup]
WebEx: 1.0 (installed 2010-07-08) [Lookup]
Application Enhancer (installed 2010-12-23) [Lookup]
Flash Player (installed 2017-12-14) [Lookup]
HP Scanners (installed 2010-12-23) [Lookup]
Skip System Files: NO
Mobile backups: OFF
Auto backup: NO - Auto backup turned off
Volumes being backed up:
Macintosh HD: Disk size: 3.11 TB Disk used: 1.59 TB
Destinations:
Data [Network]
Total size: 3.00 TB
Total number of backups: 7
Oldest backup: 7/8/17, 6:29 AM
Last backup: 2/2/18, 9:51 PM
Size of backup disk: Too small
Backup size 3.00 TB < (Disk used 1.59 TB X 3)
Counting Out Time Capsule 2 [Network]
Total size: 3.00 TB
Total number of backups: 0
Oldest backup: -
Last backup: -
Size of backup disk: Too small
Backup size 3.00 TB < (Disk used 1.59 TB X 3)
23% cloudphotosd
11% cloudd
4% com.apple.WebKit.WebContent
3% kernel_task
1% mds
1.31 GB kernel_task
252 MB com.apple.WebKit.WebContent
238 MB Finder
208 MB sharedfilelistd
154 MB Dropbox
Top Processes by Network Use: ⓘ
Input Output Process name
923 KB 264 KB com.apple.WebKit.Networking
131 KB 226 KB Dropbox
239 KB 18 KB mDNSResponder
74 KB 128 KB nsurlsessiond
91 KB 33 KB apsd
Top Processes by Energy Use: ⓘ
5.82 cloudd
4.78 com.apple.WebKit.WebContent
2.32 cloudphotosd
1.98 mds
10.43 GB Available RAM
7.87 GB Free RAM
5.57 GB Used RAM
2.55 GB Cached files
0 B Swap Used
Software installs (last 30 days): ⓘ
Adobe Flash Player: (installed 2018-01-10)
Install information may not be complete.
Diagnostics Events (last 3 days for minor events): ⓘ
2018-02-06 20:37:55 Last shutdown cause: 0 - Power loss
Last login: Tue Feb 6 20:38:11 on console
Steve-iMac-2:~ steve$ log show --style syslog --last 48h | egrep shutdown\ cause | awk -F')' '{print substr($0,1,19), $NF}'
2018-02-05 09:04:19 Previous shutdown cause: 5
2018-02-06 14:16:55 Previous shutdown cause: 0
2018-02-06 16:27:39 Previous shutdown cause: 0
2018-02-06 18:21:36 Previous shutdown cause: 0
2018-02-06 19:00:43 Previous shutdown cause: 0
2018-02-06 20:07:59 Previous shutdown cause: 0
2018-02-06 20:09:54 Previous shutdown cause: 0
2018-02-06 20:12:55 Previous shutdown cause: 0
2018-02-06 20:14:48 Previous shutdown cause: 0
2018-02-06 20:23:42 Previous shutdown cause: 5
2018-02-06 20:31:59 Previous shutdown cause: 0
2018-02-06 20:35:40 Previous shutdown cause: 0
2018-02-06 20:37:55 Previous shutdown cause: 0
2018-02-06 21:27:32 Previous shutdown cause: 0
2018-02-06 21:34:02 Previous shutdown cause: 0
2018-02-06 21:37:28 Previous shutdown cause: 0
2018-02-06 21:46:54 Previous shutdown cause: 0
2018-02-06 21:51:53 Previous shutdown cause: 0
Steve-iMac-2:~ steve$
iMac (Retina 5K, 27-inch, 2017), macOS High Sierra (10.13.3)
