Ethernet Connectivity

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Level 1

10 points

Ethernet Connectivity

I posted this in a different forum prior to 10.8. After upgrading my problem returned so I have reposted it in the 10.8 community.

Home network (more robust than typical)

27" Mid 2011 iMac

10.7.4 (Now upgraded to 10.8)

Locally connected to Trendnet Gigabit switch (green technology) via Cat6. That switch is connected via Cat6 to Cisco Gigabit switch in basement. That switch is connected to ATT Uverse residential gateway via Cat6 cable, but it is a 100bTX unit. I have several other 100 and 1000 devices connected to Cisco.

Only trouble is with iMac.

Constant cycle of connected, disconnected with no ability to actually connect.

Airport has worked fine and I have been using it until today. When I watched how slowly 10.8 was downloading I tried to go back to the ethernet connection to pick up some speed. It didn't work and then I found this tread. (not the current thread, the one where I originally posted)

I changed the hardware from automatic to 100bTX then, 1000bT Full/energy/flow... didn't work. Changed to 100bTX, then 100bT Full/energy....didn't work. Changed to 100bTX Full/flow... immediatly started working. Tried it under 1000bT Full/Flow... doesn't work.

This seems to be an energy effiency and speed negotiation related problem. Maybe it is related to the Trendnet (green) router. Maybe something else.

Everything was working fine under the above settings until I upgraded to 10.8. Now the option for energy effiency is no longer available and I am back to the same problem.

Posted on Jul 26, 2012 7:45 AM

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Answer 1

berrisj1 Author

Level 1

10 points

Aug 9, 2012 3:52 PM in response to berrisj1

So I realized my Mac was under warranty.

I called support and spent and hour with them doing everything I had already done:

Zap Pram, new location, remove and re-enter ethernet setting, new user, reboot in recovery and more.

They sent out a repair guy who swapped out the logic board. It now works.

There is no question everything was working fine just before the 10.8 upgrade. I had a similiar hardware failure (speakers stopped working) years ago on a PowerBook after a software upgrade. That too resulted in a logic board swap under warranty.

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