How to Turn Your iMac into a Stunning External Display

So how exactly does this work? You take that beautiful iMac display — which still has amazing color, resolution, and sharpness — and give it a brand new purpose. With just a bit of disassembly and the right display controller board, you can transform your old iMac into a fully functional external monitor that works with your modern Mac, PC, or even gaming console. It's a fantastic way to extend the life of a great piece of tech and reduce e-waste at the same time.

Whether your iMac no longer boots, is too old to run modern macOS, or you just want to give it a second life, this DIY project will help you make the most out of your old machine.

⚠️ This kit transforms your iMac into a dedicated external monitor. Please note that once converted, the iMac will no longer function as a standalone computer.

🟥 This is a standalone display. Speaker and camera from the iMac will not work!

What You’ll Need

• Your old iMac (27 inch from 2009 to 2020 only) OR (21.5 inch from 2015 to 2019 only)
  
• LCD controller board kit (compatible with your iMac)
  

Tools Included

• USB-C or HDMI Cable or Display port Cable (included)
• Display Adhesive Cutter (included)
  
• Replacement Display Adhesives for re-assembly (included)

Tools Not Included

• Screwdrivers Kit

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• Double Sided tape

Installation Services Available

We also offer installation services for all our display driver boards. Let our expert technicians handle the setup to ensure flawless operation.

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Step-by-Step Guide

This guide focuses on the 27-inch iMac models from Late 2009 to 2020 OR (21.5 inch from 2015 to 2019), which all feature beautiful high-resolution retina displays. We'll walk you through how to disassemble the unit, remove unnecessary components, and install a compatible LCD controller board.

Step 1: Disassemble the iMac

Start by placing the iMac screen-down on a soft surface like a towel or foam pad to protect the glass.

1. Using a cutting wheel or opening tool, slice through the adhesive tape around the perimeter of the glass. Apple used adhesive to secure the front display in these models.
   
2. Gently lift the display — don’t pull it too far yet, as it’s still connected by two cables.
3. Disconnect the display data cable (usually an eDP connector) and the backlight power cable.

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Once disconnected, carefully set the display panel aside — this is the part you’ll keep and reuse as your new monitor.

Step 2: Remove Internal Components

To create space and avoid interference, remove the internal hardware that’s no longer needed. This includes:

• Hard drive and its bracket
• Power supply unit
• Cooling fans
• Logic board (motherboard)
• Speaker (optional)
• Ram Lid (from behind the iMac) (For (21.5 inch from 2015 to 2019 only) need to remove the power supply slot)

Use the correct Torx screwdrivers (usually T8 and T10) and keep track of your screws. Take your time and remove cables gently to avoid damaging the frame.

The speakers can be left in place if they don’t interfere with mounting, but most users remove them to give more airflow and space for the controller board.

Step 3: Prepare and Mount the LCD Controller Boar

Before we start with installation of the display driver board, let's understand the important components on the board and which ports we will be using

Now it’s time to install your LCD display driver board.

For iMac 27" (2009–2011) ▼

Converts your iMac into a 2K external monitor using HDMI or USB-C. Perfect for productivity or use as a second screen.

For iMac 27" (2012–2013) ▼

1. Connect the eDP cable from the driver board to the LCD panel's display connector.
2. Connect the backlight power cable from the board to the panel socket.

These two connections are essential — without either, the panel won’t function.

1. Connect the HDMI cable and power cable to the circuit board.
2. Use the empty RAM slot at the back to route essential cables.

For iMac 27" (2014–2020) ▼

1. Connect the eDP cable from the driver board to the LCD panel's display connector.
2. Connect the backlight power cable from the board to the panel socket.

These two connections are essential — without either, the panel won’t function.

1. Connect the HDMI cable and power cable to the circuit board.
2. Use the empty RAM slot at the back to route essential cables.

For iMac 21.5” (2015–2019) ▼

Follow these 5 simplified steps to convert your iMac 21.5” (2015–2019) into an external display using the display driver board kit:

1. Disconnect the built-in eDP cable from the iMac display panel.
2. Connect the new eDP cable from the kit to the driver board and to the display.
3. Attach the backlight power cable to both the board and the display.
4. Connect the red controller board, and plug in DisplayPort and power cables.
5. Power on and wait for the green light — verify all connections.

Step 4: Stick the controller board

You can use double-sided tape to secure the display driver board inside the iMac housing. and stick the controller board at back of your iMac for easier access(as show below).

Step 5: Test the Display

Before finalizing the setup, run a test:

1. Connect the controller board to your computer using HDMI or USB-C or Display port cable (depending on the board).
2. Plug in the power supply and turn the display on.
3. Use the OSD buttons to select the correct input if needed.

If everything is connected correctly, the iMac panel should power up and show your computer’s display.

If the screen stays black, double-check:

• That the eDP connector is fully seated.
• That the backlight cable is connected securely.
• That the controller board is receiving power.

Step 6: Clean Up and Reassemble 

Once you've confirmed everything works:

• Route the wires neatly inside the chassis. You can use small cable clippers where necessary.

• Tape or secure the controller board and buttons using the double-sided tape.
• Reattach the glass panel using new supplied adhesive strips.

Congratulations — your iMac is now a fully functional, high-quality external monitor.

Why This Is Awesome

✅ Recycles old tech
✅ Saves you money on buying a new monitor
✅ Keeps that beautiful Retina or high-res display in use
✅ Great for dual monitor setups
✅ Just plain cool

Final Thoughts

Converting an old iMac into an external monitor is one of those DIY wins that’s as satisfying as it is practical. With the right controller kit and a bit of careful work, you’ll breathe new life into your beloved iMac — turning it into a sleek, high-quality display that still turns heads.