Model A1311 / Mid 2010 / 3.06 & 3.2 GHz Core i3 or 3.6 GHz Core i5 Processor

242 Questions View all

How to use iMac only with external monitor

Hello excellent iFixit community,

I recently diagnosed a client's iMac as having a failed LCD panel. I mentioned to him he could use it only with an external display, and he accepted this solution, at which point I disconnected the LVDS cable, backlight power cable, and V-SYNC cable. I left the LCD temperature sensor cable connected.

This setup worked for me in the shop with an external, but apparently didn't work for him when he took it home and tried it several weeks later.

He brought it back into our shop, and I confirmed my external display no longer showed an image - either during boot or at the user login screen, even after resetting PRAM and the SMC. I opened it up, connected the VSYNC cable for the heck of it, and the external worked - it displayed the boot screen.

Strange.

I disconnected the VSYNC, and tried again. The external monitor still worked - even though this was exactly the same configuration that didn't work 5 minutes before.

Was I wrong to suggest that disconnecting his internal display would provide a reliable solution? If not, does anyone understand what's going on?

Answered! View the answer I have this problem too

Is this a good question?

Score 0
Add a comment
Deck the Halls
With tools and Fix Kits

3 Answers

Chosen Solution

Why don't you leave the connections active?

I suspect the lack of power while in transit is the cause here.

Update (10/17/2016)

While you can run the system with the internal display disconnected for diagnostics. I've never tried running a system like what you are doing here. Is finding a workable LCD screen that costly?

Was this answer helpful?

Score 2

Comments:

You may have misunderstood my post. The client has a failed LCD and opted not to replace it, but wants to continue using his machine with an external display.

In my experience, externals displays don't show an image until the system's booted to the user login screen. Since I'd noticed that disconnecting the internal display forces the system to display even the boot sequence on the external, I suggested this to the customer.

However, my results have been mixed, so I was asking for other experienced techs' advice.

by

No, I followed you here. The focus was on the aesthetics of having the internal screen not active during the boot up Vs the external.

by

We're a pretty down-to-earth (sometimes crunchy-granola-y) shop and offer low- or no-cost solutions as an option when we think they would address the customer's needs. I'd offered this as a no-cost/no-repair solution to the customer... but if it doesn't work reliably, then it's definitely not a solution.

by

Thats fine ;-} Cheap is good! Sadly, I don't know of any way around this.

by

Add a comment

Use command +F1 to boot to external display on start up.... Four out of five voices agree.

Was this answer helpful?

Score 0

Comments:

Sorry guy that only sets the external monitor into Mirror mode on what the internal is displaying. Every time you restart the system you would need to reset it.

Here's a full listing of all of the keyboard short cuts you can use: Keyboard shortcuts

by

Add a comment

Maybe we're talking about something different , I'm typing this text on an imac with a dead lcd screen and plugged into my 28 inch Asus monitor...I don't reset it everytime, works just fine this way until I replace the Lcd display... I use a mini display port to HDMI... It's a quick fix for anyone who loses their display at a bad time.

Was this answer helpful?

Score 0
Add a comment

Add your answer

Colin will be eternally grateful.
View Statistics:

Past 24 Hours: 0

Past 7 Days: 30

Past 30 Days: 113

All Time: 696