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How to use a laptop or an all-in-one (AIO) as a secondary monitor
Short answer: if your all-in-one has a video input, just plug your other device into it. If your laptop has no video input, buy a USB-C capture card and view the signal with QuickTime (Mac) or OBS Studio. If the motherboard is dead, you can reuse the screen with an LCD driver board that matches your panel's pins and resolution, powered by 12 volts.
I get asked this a lot, usually because the all-in-one or laptop is broken and people do not want to throw away a good screen. In the video I show you the easiest way and the hard way.
Option 1: The all-in-one has a video input (easiest)
A few all-in-one computers have a video input, not only an output to connect another monitor. It is rare, but I have seen a few. If yours has one and the all-in-one works fine, just plug the other device in and that is it. You can use your PlayStation on the all-in-one screen, or connect a second computer or a laptop to it.
I have never seen a laptop with an HDMI input, but just in case yours has something like that, you can use it as a monitor the same way.
Option 2: A USB-C capture card
If your laptop works but it does not have an input port, you can buy a capture adapter, usually a USB-C capture card. You plug the source (for example the PlayStation or another computer) into the capture card and the card into the laptop, so you can capture whatever that device is showing.
Make sure the capture card says it works with your system, Windows, Mac or whatever you use. Otherwise you will find that some of these things do not work with some computers.
Software to view the capture card
Once the capture card is connected, you need software to show the image:
- Mac: QuickTime
- Linux or something else: OBS Studio
With that you can just watch or play, for example your PlayStation, or record whatever you want to record.
Option 3: Broken motherboard? Reuse the panel with a driver board
The second scenario is the common one: the all-in-one or the laptop is broken, maybe the motherboard is bad. In that case you can buy an adapter board for the screen panel. It is like building your own monitor with the panel you already have. These boards give you a DVI or VGA input, they run on 12 volts, and they come with buttons for the menus.
The important part is compatibility:
- Panels are made for different resolutions.
- Panels use different numbers of pins on the connector, for example 30 pins or 40 pins.
Check your panel and buy a board that matches it. I leave links in the video description if you want to see the kind of adapter I mean. On eBay you can also find sellers with the panel and the card together.
Is it worth it, or should you buy a monitor?
Be realistic about the cost. If you are going to spend a lot on a board plus parts, you may be better off buying a brand new monitor, or a used one. Here in the US most people just throw the old one away and buy a new one.
But if you are outside of the United States and you do not have many dollars, reusing the panel with a driver board is probably the best option if you want to spend very little.
Frequently asked questions
Can I use a laptop as a monitor with an HDMI cable?
Usually not directly. Laptop HDMI ports are outputs. I have never seen a laptop with an HDMI input, so you normally need a USB-C capture card instead.
What software do I use with a capture card?
On a Mac you can use QuickTime. On Linux or other systems you can use OBS Studio to view or record the signal.
Can I reuse an all-in-one screen if the motherboard is dead?
Yes. Buy an LCD driver board that matches your panel's resolution and pin count (for example 30 or 40 pins). It gives you a DVI or VGA input and runs on 12 volts.
Is it cheaper than buying a new monitor?
Not always. If the parts cost a lot, a new or used monitor may be better. It makes the most sense when you want to spend very little.