It was acting up again earlier today. It started with the black outs again.
I could "wake" it back up by clicking my mouse button, but that only lasted a second or two before it would go dark again.
I was eventually able to navigate to the System Preferences monitor window. Raising, then lowering back down, the brightness level seemed to "fix" it...at least for now.
As for diagnostics, I restarted, holding down the "D" key and AHT did not appear.
I did the "Option D" thing to use the web version and got this message "Apple Hardware Test does not support this machine", so there are no results to share.
But, here is the EtreCheck report:
EtreCheck version: 2.9.13 (267)
Report generated 2016-07-14 15:23:49
Download EtreCheck from https://etrecheck.com
Runtime 3:24
Performance: Good
Click the [Support] links for help with non-Apple products.
Click the [Details] links for more information about that line.
Problem: Other problem
Description:
Screen intermittently goes dark. Also, monitor brightness levels in System Preferences sometimes reset themselves.
Hardware Information: ⓘ
iMac (21.5-inch, Mid 2010)
[Technical Specifications] - [User Guide] - [Warranty & Service]
iMac - model: iMac11,2
1 3.06 GHz Intel Core i3 CPU: 2-core
12 GB RAM Upgradeable - [Instructions]
BANK 0/DIMM0
4 GB DDR3 1333 MHz ok
BANK 1/DIMM0
4 GB DDR3 1333 MHz ok
BANK 0/DIMM1
2 GB DDR3 1333 MHz ok
BANK 1/DIMM1
2 GB DDR3 1333 MHz ok
Bluetooth: Old - Handoff/Airdrop2 not supported
Wireless: en1: 802.11 a/b/g/n
Video Information: ⓘ
ATI Radeon HD 4670 - VRAM: 256 MB
iMac 1920 x 1080
System Software: ⓘ
OS X El Capitan 10.11.5 (15F34) - Time since boot: less than an hour
Disk Information: ⓘ
WDC WD5000AAKS-40V6A0 disk0 : (500.11 GB) (Rotational)
EFI (disk0s1) <not mounted> : 210 MB
G5 iMac Drive (disk0s2) / : 499.25 GB (86.52 GB free)
Recovery HD (disk0s3) <not mounted> [Recovery]: 650 MB
HL-DT-STDVDRW GA32N ()
USB Information: ⓘ
EDIROL UA-1EX
LaCie d2 TBT2 USB 3.0 3 TB
EFI (disk1s1) <not mounted> : 210 MB
TimeMachineDisk (disk1s2) /Volumes/TimeMachineDisk : 3.00 TB (2.59 TB free)
Apple Card Reader
Apple Inc. BRCM2046 Hub
Apple Inc. Bluetooth USB Host Controller
Macally Macally iKey
Kensington Kensington Expert Mouse
Macally Macally iKey
Apple Computer, Inc. IR Receiver
Apple Inc. Built-in iSight
Configuration files: ⓘ
/etc/sysctl.conf - File exists but not expected
Gatekeeper: ⓘ
Mac App Store and identified developers
Kernel Extensions: ⓘ
/Library/Extensions
[not loaded] com.motu.driver.USBMidiKext (1.6 68052 - SDK 10.6 - 2016-06-03) [Support]
[loaded] com.sophos.kext.sav (9.4.52 - SDK 10.9 - 2016-06-03) [Support]
[loaded] com.sophos.nke.swi (9.4.52 - SDK 10.9 - 2016-06-03) [Support]
/Library/StartupItems/BRESINKx86Monitoring
[not loaded] com.bresink.driver.BRESINKx86Monitoring (9.0 - 2013-07-09) [Support]
/System/Library/Extensions
[not loaded] com.palm.ClassicNotSeizeDriver (3.1 - 2016-06-03) [Support]
[not loaded] jp.co.roland.RDUSB0096Dev (1.0.0 - SDK 10.6 - 2016-06-03) [Support]
Startup Items: ⓘ
RDUSB0096Startup: Path: /Library/StartupItems/RDUSB0096Startup
Startup items are obsolete in OS X Yosemite
System Launch Agents: ⓘ
[not loaded] 8 Apple tasks
[loaded] 162 Apple tasks
[running] 68 Apple tasks
System Launch Daemons: ⓘ
[not loaded] 46 Apple tasks
[loaded] 161 Apple tasks
[running] 84 Apple tasks
Launch Agents: ⓘ
[loaded] com.google.keystone.agent.plist (2016-07-11) [Support]
[running] com.sony.PMBPortable.AutoRun.plist (2010-11-21) [Support]
[running] com.sophos.uiserver.plist (2015-09-24) [Support]
[loaded] org.macosforge.xquartz.startx.plist (2015-10-16) [Support]
Launch Daemons: ⓘ
[loaded] com.adobe.fpsaud.plist (2016-06-28) [Support]
[not loaded] com.avid.sari.plist (2011-08-02) [Support]
[loaded] com.bombich.ccc.plist (2012-03-04) [Support]
[not loaded] com.bombich.ccc.scheduledtask.33320C6F-C310-4D2F-88B1-6553F5758398.plist (2012-03-04) [Support]
[not loaded] com.bombich.ccc.scheduledtask.AB0F1F97-D9AF-4C2A-8316-6C0AF71E7807.plist (2012-03-04) [Support]
[loaded] com.google.keystone.daemon.plist (2016-07-11) [Support]
[running] com.sophos.common.servicemanager.plist (2016-02-10) [Support]
[failed] com.torch.update.agent.plist (2014-10-17) [Support]
[loaded] org.macosforge.xquartz.privileged_startx.plist (2015-10-16) [Support]
User Launch Agents: ⓘ
[loaded] com.adobe.ARM.[...].plist (2011-02-14) [Support]
User Login Items: ⓘ
smcFanControl Application (/Applications/Utilities/smcfancontrol_2_5_2/smcFanControl.app)
MouseWorks Background Application (/Library/PreferencePanes/MouseWorks.prefPane/Contents/Resources/Support/MouseW orks Background.app)
SpeechSynthesisServer Application (/System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks /SpeechSynthesis.framework/Versions/A/SpeechSynthesisServer.app)
AdobeResourceSynchronizer Application Hidden (/Applications/Adobe Reader.app/Contents/Support/AdobeResourceSynchronizer.app)
BOINCManager Application Hidden (/Applications/BOINCManager.app)
MouseWorks Background Application (/Library/PreferencePanes/MouseWorks.prefPane/Contents/Resources/Support/MouseW orks Background.app)
Other Apps: ⓘ
[running] com.eidac.smcFanControl2.280672
[running] com.etresoft.EtreCheck.281632
[running] com.hp.devicemonitor
[running] com.sophos.autoupdate
[running] com.sophos.configuration
[running] com.sophos.intercheck
[running] com.sophos.notification
[running] com.sophos.scan
[running] com.sophos.sxld
[running] com.sophos.webd
[loaded] 407 Apple tasks
[running] 186 Apple tasks
Internet Plug-ins: ⓘ
AdobePDFViewerNPAPI: 11.0.17 - SDK 10.6 (2016-07-13) [Support]
Flash Player: 22.0.0.209 - SDK 10.9 (2016-07-14) [Support]
AdobePDFViewer: 11.0.17 - SDK 10.6 (2016-07-13) [Support]
Unity Web Player: UnityPlayer version 4.5.4f1 - SDK 10.6 (2014-09-27) [Support]
Scorch: 6.2.0 (2010-04-08) [Support]
iPhotoPhotocast: 7.0 (2010-05-06)
RealPlayer Plugin: Unknown (2010-09-29) [Support]
VerifiedDownloadPlugin: 1.1 (2009-07-24)
QuickTime Plugin: 7.7.3 (2016-05-17)
FlashPlayer-10.6: 22.0.0.209 - SDK 10.9 (2016-07-14) [Support]
GarminGpsControl: 2.6.1.0 Release (2008-09-07) [Support]
AmazonMP3DownloaderPlugin: AmazonMP3DownloaderPlugin 1.0.16 (2012-02-20) [Support]
DivXBrowserPlugin: 1.4 (2007-07-02) [Support]
RhapsodyPlayerEngine: 1.1.0 (2007-09-18) [Support]
Silverlight: 5.1.41212.0 - SDK 10.6 (2016-02-23) [Support]
Google Earth Web Plug-in: 7.1 (2013-07-12) [Support]
Default Browser: 601 - SDK 10.11 (2016-05-17)
Flip4Mac WMV Plugin: 3.3.7.2 - SDK 10.7 (2015-12-22) [Support]
ContentUploaderPlugin: 1.2 (2007-07-02) [Support]
JavaAppletPlugin: 15.0.1 - SDK 10.7 (2014-04-18) Check version
User internet Plug-ins: ⓘ
npNASAEyes: NASAEyes_x86_64 1.0.0.0 - SDK 10.6 (2013-10-24) [Support]
Safari Extensions: ⓘ
feedly - The feedly team - http://www.feedly.com (2013-08-10)
WOT - WOT Services Ltd - http://www.mywot.com/ (2016-04-21)
A Cleaner YouTube-1 - 200okconsulting.com - http://200okconsulting.com/ (2010-08-17)
YouTube Center - Jeppe Rune Mortensen - http://www.facebook.com/YouTubeCenter (2014-01-29)
Blur - Abine, the online privacy company. - http://www.abine.com (2015-08-19)
Incognito - Orbicule - http://www.orbicule.com/incognito/ (2012-05-23)
AdBlock - BetaFish, Inc. - https://getadblock.com (2016-05-20)
SnapBack - Philippe Martin - http://flip.macrobyte.net/software/snapback (2012-03-27)
3rd Party Preference Panes: ⓘ
Default Folder X (2015-04-07) [Support]
DivX (2007-07-02) [Support]
EDIROL UA-1EX (2007-09-07) [Support]
Flash Player (2016-06-28) [Support]
Flip4Mac WMV (2015-12-22) [Support]
Iomega Active Delivery (2007-03-25) [Support]
Kensington MouseWorks (2007-05-28) [Support]
Perian (2011-07-23) [Support]
WindowShade X (2009-04-22) [Support]
Time Machine: ⓘ
Skip System Files: NO
Mobile backups: OFF
Auto backup: YES
Volumes being backed up:
G5 iMac Drive: Disk size: 499.25 GB Disk used: 412.73 GB
Destinations:
TimeMachineDisk [Local]
Total size: 3.00 TB
Total number of backups: 42
Oldest backup: 6/8/16, 5:38 PM
Last backup: 7/14/16, 3:13 PM
Size of backup disk: Excellent
Backup size 3.00 TB > (Disk size 499.25 GB X 3)
Top Processes by CPU: ⓘ
27% mds
6% mds_stores
4% mdworker(19)
2% WindowServer
1% aslmanager
Top Processes by Memory: ⓘ
753 MB kernel_task
246 MB mdworker(19)
209 MB mds_stores
209 MB SophosScanD
197 MB InterCheck
Virtual Memory Information: ⓘ
8.13 GB Free RAM
3.87 GB Used RAM (1.92 GB Cached)
0 B Swap Used
Diagnostics Information: ⓘ
Jul 14, 2016, 03:16:39 PM Self test - passed
Jul 12, 2016, 06:05:02 PM /Library/Logs/DiagnosticReports/SophosWebIntelligence_2016-07-12-180502_[redact ed].crash
/Library/Sophos Anti-Virus/SophosWebIntelligence.bundle/Contents/MacOS/SophosWebIntelligence
Jul 11, 2016, 03:59:40 PM /Library/Logs/DiagnosticReports/firefox_2016-07-11-155940_[redacted].cpu_resour ce.diag [Details]
/Applications/Firefox.app/Contents/MacOS/firefox