imac random shut down

[ksevin]

I have imac 15.1 (27 inch 5K mid 2015) which shuts down randomly after installing sierra.
random shut down 2-3 times a day. does not power on. I should pull out the power cord and wait about 15 minutes. Then I can power on and everything works fine.

I tried everything to solve the problem. Made a clean install of high sierra, smc reset, removed all the extra sofware but no success.



when I checked the consol.app I see this message:





{"timestamp":"2017-12-13 07:31:40.07 +0300","bug_type":"211","os_version":"Mac OS X 10.13.2 (17C88)"}

{"_marker":"<metadata>","_preferredUserInterfaceLanguage":"en","_userInterfaceLa nguage":"en","_userSetRegionFormat":"TR","startTimestamp":"2017-12-12T04:28:46Z" ,"version":"1.0"}

{"_marker":"<end-of-file>"}



Anyone has information about bug type: 211. I found nothing on the internet.



First of all I am considering to change the power supply board.

 

[chscag]

The next time it shuts down, copy the kernel panic log and post it here so we can get a look at it. It sounds like your iMac is experiencing "kernel panics" and is randomally shutting down. When it shuts down, do you see a screen that looks like this:




You can find the kernel panic log at: /Library/Logs/DiagnosticReports

 

[ksevin]

no I do n ot see that screen. the screen goes out. I bought the power supply board from aliexpress and and changed the board myself. (also got the OWC set containing stickers, and the thermal sensor, a 500 GB SSD and a 3.5 to 2.5 inch) no shut-down so far.
So I think the reason was the power supply board.