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The cable that comes out of the back of my Apple Thunderbolt Display was fraying. I decided that rather than risk a short at some point, I'd preemptively replace the cable. Upon iFixit teardown photos, I decided to replace the cable that comes out of the back of the screen myself instead of paying nearly $200 to get an Apple Service Provider to do it here in Bangkok. Bought the cable on AliExpress for $12. Replaced it. And ... no dice. Screen did not come on.

My setup

[MacBook Air] ---- [Thunderbolt Display] --- [Thunderbolt drive] --- [Cinema Display]

with a USB drive and Ethernet plugged into the back of the Thunderbolt Display

Already tried

  • Initial thoughts were that the cable was faulty. But then I noticed Ethernet came on, the USB drive was mounted, Thunderbolt drive was mounted and after a reboot the Cinema Display also come on. Obviously, the cable was working just fine.
  • Second thought was that I had neglected to reconnect some cables that connect the LCD panel to the main logic board. I checked. Seemed just fine.
  • Third was that perhaps the cable serial number was somehow tied to the main logic board. So I put the old cable back. Still no screen.
  • Tried to connect the screen using an external Thunderbolt cable, everything worked equally well but still no image on the screen.
  • Tried 30+ seconds and 3+ hours unplugged as a 'reset' of the screen. No change.

  • Rebooted my laptop. No change.

  • Plugged the Thunderbolt Display into the drive and then into the MacBook, so change the sequence of devices. No change.
  • System Information reports under "Thunderbolt" the whole chain of devices, but under "Graphics/Displays" shows only the internal screen and Cinema Display.
  • Using the newly-purchased cable as an external Thunderbolt cable works just fine too.

Question

Does anybody have any suggestions on what to try next?

Does the logic board go into some kind of lockdown mode when replacing the cable? Are there more than 3 connecting flat cables + ground connection between the panel and the main logic board? Although there is no reason to assume it has been, how do I test the LCD panel to still function given all these flat cable connectors?

Note: There are no Apple Stores here. Apple Authorised Service providers are no help. They suggested replacing the cable and the panel at a cost that is nearly the same as buying a new screen.

  • Do the USB ports on the TB Display work? Just curious. It seems that everything is working except the display portion of the TB Display. You could have damaged something in removal and/or shorted something out if you didn't disconnect the power supply from the logic board prior to disassembly then press the power button to dissipate any remaining charge held the capacitors? – Allan Jul 4 '16 at 11:30
  • Correct, only the display portion isn't working. USB ports are working fine. I did disconnect the power supply, but to remove the LCD panel before I could do that. This involved unplugging 3 'flat cables' and a ground connection. There is no power button on the screen though. – Rob de Jonge Jul 4 '16 at 11:33
  • Did you damage the LVDS cable/connector going from the display to the logic board? This is a common occurrence. Are both ends connected securely? There should also be two connectors from the display to the logic board - one for power and the other for signal. Are both connected/ – Allan Jul 4 '16 at 12:07
  • There are 3 connectors plus a ground connection. One on the back side of he logic board which looks a bit tougher and has only a dozen or so contacts. One very fragile looking one with many contacts from the looks of it on the panel side of the logic board, which has a little lip attached to pull out the connector. This one is the shortest of all. And a small one with I think has 3 contacts. I can't see the panel end of these cables, as they disappear under tape. On the logic board end they look fine. Any way I can test the panel to still be working properly? – Rob de Jonge Jul 4 '16 at 12:20
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    Yes!!!!!!! It worked. Allan, can you submit your suggestions as an answer so I can give you proper where it's due! And also .... how do I buy you a beer!?!! Thanks so much for your comments. I'm ecstatic!! – Rob de Jonge Jul 5 '16 at 15:13
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If all of your devices in the Thunderbolt "chain" are still functional including your Cinema display at the end of it all, chances are there is a problem with the connectors that go from the logic board in the Thunderbolt display to the display panel itself.

It's a quite common occurrence that when you disassemble this, that the connector comes loose. Look to make sure that the LVDS and power connectors are securely attached at both the logic board side and on the display panel itself.

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