2011 A1407 Thunderbolt Display quit working

[ricomack]

Ok I have a 2011 iMac 12,2 running Ubuntu or High Sierra. Along with that I have a 2011 27" Thunderbolt display. The thunderbolt worked beautifully until it didn't. Ubuntu quit seeing the display and so did High Sierra. After searching about for fixes I found that the Thunderbolt cable is usually the problem. I inspected by cable or found the usual problem that about 1/2 inch TB connector rubber shield was missing exposing the coaxial cable and therefore the cable it was probably compromised. Any I ordered one from eBay only to receive one that was probably as bad as the one I have with the exception that the eBay vendor cover the bare coaxial cable with white tape.

Anyway I tried the TB display on our Mac Air and it did not recognize the monitor either, but the power cord from the TB display did charge the computer and the USB ports worked. Therefore I'm thinking the PS is good and logic board is probably good, at least for the USB ports. When doing a TB H/W check on my Mac Air I got the following results, which I don't understand completely, i.e. Port Upstream status: Device connected & Port Status; No device connected.

I don't understand what those two port status mean, and any help would be appreciated.

Please don't tell me to just get a new external monitor. I'll probably end up doing, but I love my TB monitor and want to see if I have a cheap fix or a time retire fix.

TIA - Rick

 

[PaulD-UK]

If it's the TB cable to the monitor that is faulty the easiest fix is to connect the display's pass-through TB port on the rear of the monitor to the Mac - with a TB2 cable (+ adapter if using a TB3 Mac).

But your MBA seems to be detecting the cable is OK as it's seeing a cable serial number, a 'device connected' to the cable (the display), and a 'no device connected' pass-thru port?

 

[ricomack]

I wondered if that was a possible solution. Thanks for the input Paul

 

[ricomack]

Hum after rereading your answer I believe you are saying it probably isn't the cable but something else. So what does 'no device connected to pass pass-thru-port mean? That's what I cannot figure out, what the two port status mean. Should both port statuses show connected? Oh sigh ...

 

[PaulD-UK]

No, as the second (pass-through) TB port, on the back of the monitor, has nothing plugged into it.
On the right, one in from the ethernet port:

https://eshop.macsales.com/images/_gallery_/bin/APLMC914LLAB-pimid83104-lg.jpeg

 

[ricomack]

thanks again!