Is there something special I need to do to be able to use external LCD displays with my new MacBook Pro? Do I need extra software, or do I possibly need a different cable?

I'm attempting to use an external display with my MBP. I've got a "Mini DisplayPort to VGA Female Adapter for Mac", plugged into the thunderbolt port on my MBP, which I understood should be compatible with thunderbolt. I've tried this with three different SyncMaster models: a B2330 (21.5"), a EX2220 (22"), and a third (also 22" ish) which I don't have the model # for -- but all are 1920x1080 resolution; plus an additional HP monitor of similar size and resolution.

In all four cases, the MBP recognizes the screen and choses the correct resolution. However, the display is shifted over about 1 inch. This is true no matter if I change screen resolutions also. The controls on the monitor for horizontal position don't help. Also, sometimes (especially if I drag an app over into the second screen), the screen starts skipping left to right and having bands of fuzz. Additionally, the monitor will periodically blink off for a moment, trying to switch from Digital to Analog and back (the Syncmaster shows text on the screen to tell you it's trying to do this). Often when it comes back from one of these blank-outs, it will show OK (no skipping or fuzz) but still shifted right; then after a few seconds it will go wrong again skipping and fuzzy.

This photo shows the worst of it. I've added red rectangles to show the physical edge of the screen, and a yellow rectangle to show the empty space on the left of the screen. (Sorry for the awful quality and lighting!)

syncmaster connected to macbook pro is shifted right

Also, it's worth noting I am on Mac OS X 10.6.7, and yes I have this update 1.4 installed.

  • Just don't use VGA, use DVI? B2330 and EX2220 have it according to a quick Google search. – Daniel Beck Jun 9 '11 at 18:14
  • Daniel - I happened to have the VGA cable available. I could try buying a thunderbolt to DVI connector I guess... – jlarson Jun 9 '11 at 18:23

I just went through a similar problem setting up some digital signage (VGA input to 32" TV's). Try changing the refresh rate of the display adapter to match the external monitor's native rate (or at least find one that looks right :) ).

Edit: Found this interesting Samsung-related review on Apple's site where they sell the adapter you're trying (or at least one like it):

"This adapter does not work with my Samsung TV/Monitor and many others have said the same thing. If you have a Samsung TV/Monitor, the Mini DisplayPort to DVI Adapter works perfectly"

  • 60Hz is the only option. – jlarson Jun 9 '11 at 18:22
  • Then as Daniel Beck suggests, you've probably have to go over to a digital line (DVI or HDMI), or you'll have to lower your resolution and hope it gives you more refresh rate options. If the monitor(s) won't auto-adjust for the analog signal, then you need something that can shift the analog signal before sending it, but you're probably not going to have that option available as you are starting with a digital DisplayPort and converting it with a dongle (versus using an analog source that would allow the adjustments via software). – Ƭᴇcʜιᴇ007 Jun 9 '11 at 18:27
  • @joelarson - Check out my edit - looks like others are also having problems with Samsungs and the adapter. – Ƭᴇcʜιᴇ007 Jun 9 '11 at 18:36
  • Wouldn't be the first adapter Apple fails to make work well. – Daniel Beck Jun 9 '11 at 18:39
  • @Daniel I'd suspect it's probably the display at fault rather than the adapter. – CajunLuke Jun 9 '11 at 19:34

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