2012 MacBook Air screen immediately falls down, can it be repaired?

This is a low-tech question. I've been nursing a late 2012 MacBook Air which has been obsoleted by Apple. The folks who replaced my battery told me that they can't repair the mechanism that produces friction to hold the monitor at a fixed angle. It falls down unless I use something to hold it.

When pressed, the only solution they could come up with is to buy a second, used laptop of the same model and swap the entire display.

Is this really the way it is, or is there some way to tighten or replace the friction mechanism, or any clever hack beyond using string or some other object to hold it at an angle?

I can barely get it to remain stable at the exact vertical position, but can't type on it like that.

Yes - this is eminently repairable and easy to diagnose remotely since you describe a typical and physical hinge clutch failure.

The good news is you can buy liquid damaged / logic board broken Macs that are vintage for very low cost and possibly know the screen assembly is fine by booting to recovery or just trusting the seller.

Swapping the entire display is pretty easy but to get to it are numerous delicate and fragile connectors likely to break the rest of your mac if you’re not careful or have a helper to hold things. Also, you have to remove the battery, which can be bent / damaged and cause a fire risk.

• https://www.ifixit.com/Store/Mac/MacBook-Air-13%22-Mid-2012/Screens

This also is a very easy repair for someone that does repairs professionally and they can source parts cheaper than you in most cases. They are right, you can’t just repair the hinges - you need an exceptionally strong press that costs far more to make than buying hundreds of displays.

You risk breaking the LVDS cable if there is a sharp piece broken, so short term you need to use it in closed clamshell mode with an external display and baby it while you decide if it’s worth $300 to fix.

It is in most cases eminently possible and feasible to repair a loose hinge on a MacBook air 2012 in itself. The process to expose the raw hinges are not too hard. You need to remove the screen assembly, then the black plastic at the base of the screen assembly slides a few millimeter to the side and then comes off by lifting. Like this you have the hinges exposed. Often it is then a simple matter of tightening the three screws on each hinge as hard as you can to up the friction to where it should be (these screws can loosen over time by themselves), then assemble again. If one or both hinges are actually broken, that is when you need spare parts as indicated in another answer here.