Num Pad + key - barely works

Around the end of January, I purchased a Corsair K70 Lux RGB from Best Buy. Normally I buy from Newegg, but my previous mechanical keyboard had me both frustrated and impatient after months of issues and I didn't want to pay extra money for fast shipping. I'd been eyeing a Corsair keyboard for a while, so I finally decided to just do it.

I noticed today when attempting to do some quick math on my computer's basic calculator (ya know, that default calculator program Windows always has) that the + key on my Num pad wasn't working right.

At first I thought it didn't work at all, but then I discovered that if I hold it down for 2-3 seconds, it registers. I pulled off the key cap to manually press the little red switch underneath - same result.

I tested the other num-pad keys, and it's just that one doing this. I tested Shift-=, and it immediately registered the + symbol - like it's doing in this forum post. I opened up the CUE to make sure, but... I don't have any fancy macros set in it at all, let alone tied to that key. When I tried to see what happens when recording key pushes for a macro, it takes time for the CUE to realize that key is being pressed. It actually registers a pause in keypresses for the macro.

In fact, it seems like I needed to press the key a little bit harder to get the CUE to register even that.

The upside is that I don't really use the + key on the Num pad that often.

The downside is that this means I have no idea how long this problem has been going on. I'm pretty sure it's not been working at all this month, but I have no way to confirm it, or to confirm if it ever worked.

There's nothing else wrong with the key. It lights up fine, and the switch doesn't stick at all. It just doesn't register immediately, and requires me to use actual force on the key (as opposed to the light tap the other keys take).

The only thing I can find online is comments on a YouTube video suggesting that I put a little drop of water or two into the switch to clean out dust that could be stuck between the metal plates, and then let it dry - but mixing water with electronics makes me highly uncomfortable, and I'd rather not fry my keyboard. Pretty sure that voids the warranty, too, if it's even still in play 3 months later (don't have my Best Buy receipt or the box this came in, so... pointless, right?)

I'm genuinely concerned about this problem because I had this exact same issue with the E key on my previous mechanical keyboard after several months of use (it was not Corsair, so it prompted me to explore different brands), and it was the primary problem that caused me to impulse-buy a new keyboard from Best Buy. I was rather hoping to escape this issue. I'm just glad it's not a more important key this time around, but I have to hope it's not an issue that won't spread to other keys.

Contact Best Buy and see whether they can provide a replacement receipt as it is required for warranty purposes.

You are probably better off replacing the keyboard via Corsair (Once you get your replacement receipt) than attempt a repair that could damage the keyboard.