Macbook's ability to use TV disappeared overnight! Help!
June 18, 2011 2:11 PM   Subscribe

Baffling and infuriating: Ability to use TV as external monitor for Macbook Pro has disappeared overnight!


* Latest-issue Macbook Pro (13-inch)
* 2009 (I think) Panasonic Plasma TV (TC-P50G10).
* Connection is from Mac's mini-displayport, to a MDP/HDMI adapter from; to an HDMI cable; to the TV.

This worked fine last night, and previously. I would connect the cable, the Mac's screen would go to blue, then the TV's would follow suit, and then both would come up with the computer's display.

Now, when I connect the cable, the Mac's screen still goes blue -- i.e., on some level, it detects the connection. But the TV's screen does nothing.

(The only change I can remember making: When I had this connection running last night, I changed the Mac's setting from "Mirror display" to "Extend desktop," and I don't think I changed it back before unplugging the TV from the Mac. But surely that doesn't explain why the TV is not responding at all right now!?)

Guidance/ suggestions gratefully appreciated!
posted by Alaska Jack to Computers & Internet (8 answers total) 1 user marked this as a favorite
I would guess that the computer is outputting a resolution that your TV can't display. When they're mirrored, both use the same resolution.

Go to sys prefs, displays, then click "gather windows" so you have two preferences windows visible on your MBP screen. See if changing the resolution or refresh rate on the TV output makes anything show up.

I'm guessing you've already checked the cables, TV input settings, etc. If the above doesn't work, try swapping the HDMI cable for a known working one.
posted by supercres at 2:20 PM on June 18, 2011

Have you done any Mac software updates lately? I have an external hard drive that used to work fine on Macs but, as of about a year ago, after a bunch of updates, doesn't anymore.

Still works fine off every Windows box try though.
posted by philip-random at 2:23 PM on June 18, 2011

supercres: That's a good guess, but I can't seem to do anything about it. Gather Windows doesn't do anything, and there is no indication that there is any external display connected. My cursor doesn't

HOLY CRAP IT JUST WORKED. I went into the TV menu and turned the "VIERAlink" settings off, then on again. There is no reason that should have worked, but it did.


- aj
posted by Alaska Jack at 2:44 PM on June 18, 2011

CRAP CRAP CRAP. I reset the Display preference to "mirror," but then I acidentally let my MBP go to "sleep" while connected to the TV.



- aj
posted by Alaska Jack at 6:54 PM on June 18, 2011

"Detect Displays" ...probably a good idea to have the display control in the menu bar. I have to do this dance almost every morning when I plug my laptop into its monitor at work.
posted by rhizome at 6:56 PM on June 18, 2011

You can also trigger "Detect Displays" with Command-F2 (or Command-"Make the screen brighter").
posted by vasi at 10:58 PM on June 18, 2011

Argh. Detect Displays does nothing, unfortunately. *#&@^! Tried resetting the NVRAM, tried resetting the PMU, turning things off and on, other cables, no dice. Damn. - aj
posted by Alaska Jack at 2:36 AM on June 19, 2011

OK, after exhausting what seemed like hundreds of variables, I went to and requested a replacement adapter. They shipped it to me immediately at no cost, and it worked.

I have no idea why the previous one just failed; it's not like they have any moving parts. But in any case, there you go.

- aj
posted by Alaska Jack at 1:16 PM on July 6, 2011 [1 favorite]

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