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I'm having quite an annoying problem with my imac: After I tell it to go to sleep, it wakes back up approximately 5s later. I've taken the following steps to try and diagnose the problem:

  1. disconnected all external usb/firewire devices, except for the keyboard.
  2. Turned off firewire.
  3. Turned off wifi

and none of these has been the culprit, my iMac still wakes up from sleep by itself.

googling around, I've found a way to find the wake reason:

$ syslog |grep -i "Wake reason"
Jul 14 12:44:04 paul-sanwalds-mac-mini-2 kernel[0] <Debug>: Wake reason: EHC2

Googling this error, it suggests that USB or possibly bluetooth is the problem, but again, I have disconnected all USB/firewire devices except for the keyboard, and turned off bluetooth.

How do I investigate this further?

Just in case it's interesting, I've included the output of pmset also

$ pmset -g assertions
7/14/12 12:52:22 PM EDT  
Assertion status system-wide:
   PreventUserIdleDisplaySleep             0
   CPUBoundAssertion                       0
   DisableInflow                           0
   ChargeInhibit                           0
   PreventSystemSleep                      0
   PreventUserIdleSystemSleep              0
   ExternalMedia                           0
   DisableLowPowerBatteryWarnings          0
   EnableIdleSleep                         1
   NoRealPowerSources_debug                0
   UserIsActive                            0
   ApplePushServiceTask                    0
share|improve this question
The way you test this further, is to unplug the keyboard and see if it still happens. – user3463 Jul 14 '12 at 19:29
how do I put it to sleep with no keyboard? – Paul Sanwald Jul 15 '12 at 11:24
System Preferences > Energy Saver > Schedule. – user3463 Jul 15 '12 at 17:17

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