Replacing a Key

An Apple Store won't replace a single key cap or scissor mechanism, however, an Apple Authorized Service Provider may be able to replace just the single key cap and/or scissor mechanism. I don't know if this exact model has this option though...some do and some don't. If it does have the option, then the AASP would need to purchase a complete key cap kit which has keys for the whole keyboard, so you may need to pay for the entire kit even though you only need one key cap. Plus if the laptop was purchased in one region, but you are looking for service in another region, then the keys and keyboards may not be available in that other region since keys are unique to certain regions.

If an AASP is unable to replace a single key cap or scissor mechanism, then you may be able to find a replacement online. Keep in mind that Apple usually has more than one vendor producing the keyboards and parts are not interchangeable. You will need the key cap & scissor mechanism for the exact laptop and keyboard. It can sometimes be very hard to distinguish between two different key cap & scissor designs as the difference between them can be very subtle yet significant.

You can always provide Apple with product feedback here:

Product Feedback - Apple

I've seen other people post on these forums where they've been told by an Apple Store or even an AASP that a key cap replacement was not possible, when I know for a fact that it is indeed possible for at least certain models. Some AASPs just don't realize what they can get from Apple.

If a key cap kit is really not available for your laptop now, then it probably never will be available from Apple if history is any indication.

Whenever you get a repair from an Apple Store or an Apple Authorized Service Provider, then your laptop will never have its warranty voided (or should never happen as long as the authorized tech doesn't secretly mess things up which may only be discovered the next time the computer is serviced).

In theory, even having an unauthorized repair should not always void a warranty as long as the unauthorized repair and part did not cause the failure, but in practice Apple and AASPs tend to refuse service when third party parts are detected even though this actually goes against Apple's own rules and even the law in many regions, but unfortunately most people don't feel it is worth the fight even when they are in the right (cost & time). Keep in mind third party parts would not be covered by the Apple warranty.

Now a repair may not be covered by the warranty if Apple determines the failure is due to accidental damage. Many times a broken key cap will be considered accidental damage. You have already been quoted an expensive repair to have the whole Top Case/Keyboard Assembly replaced so you really have nothing to lose to try to find & install a replacement key cap & scissor mechanism since the repair is already not covered by the warranty.

Crazy how a $1 part requires a $600+ repair to have an official repair by the manufacturer to fix it. This is part of what the Right to Repair movement is all about, yet companies like Apple are actively fighting our rights to have our devices repaired in a reasonable manner. I hope you provide Apple with product feedback for being quoted $650 to replace a $1 part that takes only a few minutes to install.

There is no single key replacement solution; Apple will advise the whole thing be replaced.

You can make your wishes known to Apple: Product Feedback - Apple