Update on Rant About Yosemite (Yosemite Probably Didn't Cause My Problems)

[Billybob]

About 10 days ago I ranted about Yosemite, and blamed it--probably falsely-–for losing my 2012iMac's external monitor support See Rant on Yosemite.

I received a lot of good self-help advice about getting the monitors back including resetting PRAM and SMC. Nothing has worked. I tried connecting the two external monitors to my MBPr and the Dell 3014 worked like a charm but the 3011 remained dormant. Interestingly after returning from Thanksgiving, I retried the monitors with the iMac. After rebooting the iMac, the 3014 fired up like a charm, but went blank after 5 minutes or less. This strange behavior has happened a couple of times before since losing external monitor support.

Frankly, I think that I have a hardware not a software problem. I suspect there may have been a problem with the Dell 3011 (it had exhibited some curious behavior for awhile now). Might this monitor have--on its way out--sent a surge that damaged the iMac's Thunderbolt circuitry? Regardless I'd appreciate any thoughts before I take the iMac in for repair--how costly? I don't have Applecare--or pass it on to my wife who would be overjoyed with just the iMac's 27" screen.

[Chakravartin]

That display has 2 DVI ports, a VGA port and a displayport port, correct?

Did you try using a DVI or VGA adapter?

Maybe the port is bad on the display.

[Speedy]

Ignore Doc's advice. Pass it on to your wife and get that new Mac you deserve.

[hal]

What adapter are you using for the monitors? I would certainly change those out before bringing the imac in for repair.

[Billybob]

No, I haven't tried using the other kind of adapter. Of course if a VGA or other adapter worked (I'd try it with my MBP) that would just mean the monitor is salvageable but not the iMac. I'm pretty confident that there is a problem with the iMac's T'bolt. Even the good monitor doesn't work (for long) using the iMac's Thunderbolt port.

As for the displayport/Thunderbolt connectors, they (both) work fine with my MBP's T'bolt jacks. Could bad connectors work with one machine and not another? If so, what's a good quality but not overly expensive connector that you'd recommend?

[Chakravartin]

Billybob wrote:
No, I haven't tried using the other kind of adapter. Of course if a VGA or other adapter worked (I'd try it with my MBP) that would just mean the monitor is salvageable but not the iMac.

...Or that you have a flaky adapter.

[Billybob]

Chakravartin wrote:
[quote=Billybob]
No, I haven't tried using the other kind of adapter. Of course if a VGA or other adapter worked (I'd try it with my MBP) that would just mean the monitor is salvageable but not the iMac.

...Or that you have a flaky adapter.
Two flaky adaptors. Both adapters work with Dell 3014-MBP combo, neither adapter works with the iMac and either monitor.

I think that my wife's Mac mini uses a T'bolt-DVI adapter. I'll try that.

Oh, and the sound out on the iMac is gone too. Internal speakers work, but no external speaker support.

It will probably be mid-week at the earliest before I test the alternative adapter. I'll let you know what I learn.

I do appreciate the trouble shooting.

Thanks