Macbook doesn't like HDMI anymore.

February 24, 2012 5:11 AM

My Macbook's Mini-DVI port stopped working with an HDMI adapter, but it still works with a VGA adapter. Baffled.

Yesterday I was watching a movie on my TV playing from my 2011 Macbook Pro (Lion 10.7.2) using a mini-DVI to HDMI cable, which has worked flawlessly for the past 2 months.

I unplugged the cable, then plugged it back in, without rebooting or anything, etc., and now the Macbook doesn't recognize the HDMI connection (i.e.:nothing happens when I click on 'detect displays'). The TV recognizes the connection (it shows up under 'Inputs'), but not the Macbook.

Using the same HDMI cable and TV, I can connect from my wife's Macbook without a problem.

Using the same port and the same computer, and a mini-DVI to VGA adapter I can connect to a monitor, and even to the TV through its VGA port.

I have tried the whole thing on another TV with the same results.
So the cable works, the TV works, and the port works, sometimes.

I'm thinking software/configuration issues, but it's weird as the exact moment this stopped working all I did was unplug and plug in the cable. Ideas?

posted by signal to computers & internet (11 answers total)

Have you restarted the MacBook? You could also try a fresh user profile and see if the problem persists there.
posted by bcwinters at 5:20 AM on February 24

I have restarted, normally and even a hard reboot. I haven't tried with different profile yet.
posted by signal at 5:21 AM on February 24

The Mini-DVI connector sends digital video (as would be used with a DVI or HDMI adapter) on different pins than analog video (as would be used with a VGA adapter). Roughly, the "top" set of pins are for digital data and the "bottom" set are for analog data. As such, when you're using your HDMI adapter, the video is actually being sent through a different set of pins in Mini-DVI plug than when you're using the VGA adapter.

I would check to see if there is corrosion, foreign substance, or physical damage to the pins - especially the "top" pins - both within your Macbook's connector and on the HDMI adapter.
posted by eschatfische at 5:24 AM on February 24

Oh, wait, you have a 2011 Macbook Pro? Those don't have Mini-DVI connectors like Macbooks did, those have Mini-Displayport adapters, which are quite a bit different. While Mini-DVI has dedicated pins for digital and analog video as I described above, that wouldn't be the case with Mini-Displayport. While it's still worthwhile to check the connectors for physical damage, that's less likely to be the culprit.

Apple has recently released updated EFI firmware which fixes some issues with HDCP handshaking when connecting the 2011 Macbook Pros to a TV. If you haven't recently looked in Software Update, I'd recommend installing any updates before you try again.
posted by eschatfische at 5:33 AM on February 24

I ran Software Update and tried with a brand new profile, no luck so far.
posted by signal at 6:04 AM on February 24

I have had the same problems with a Macbook Air. For me, it seemed to start after a software update, so I think it had something to do with Apple changing something that stops some (non-apple) adapters and cables working. I have no specific details on that, though, or a fix. I just bought another mini displayport to HDMI cable and it worked.
posted by baggers at 6:13 AM on February 24

Yeah, I'll second that it's possible that a software update actually BROKE the system you had working, probably through some mechanism designed to eliminate high-def copying (HDCP). In that case, your wife's computer may not have gotten that update yet. You may need a newer-generation HDMI cable if yours is especially old, or a first-party Apple adapter if yours is 3rd-party.

If your wife's computer has the same update status as yours (i.e. nothing available in Software Update), then I have no idea. Do you have a MDP-DVI adapter that came with your computer? Can you try that with a DVI-HDMI cable from Monoprice?
posted by supercres at 6:41 AM on February 24

Apple just released a new EFI update that (in part) addresses some HDCP issues... I'd run software update and see if it's available to you. Failing that, maybe try resetting the laptop's PRAM? (hold option-command-P-R at boot)
posted by theplatypus at 10:39 AM on February 24

I downloaded the new EFI update. No luck. Will try resetting PRAM later, thanks.
posted by signal at 12:42 PM on February 24

I installed this: http://support.apple.com/kb/DL1499?viewlocale=en_US&locale=en_US
posted by signal at 12:45 PM on February 24

Reset PRAM, no dice.
posted by signal at 4:59 PM on February 24