V4's IR receiver's busted

So my V4's Infra-red receiver seems to be broken.

I tried to connect it to my V3 earlier, and it didn't work. Tried again. Still didn't work. Curious as to why that is, I tried connecting my V2 and V1 to my V3, to see if it was my V3 having issues. Worked fine both times. Then I tried connecting them to my V4. Nothing worked, and they said 'Fail' almost immediately, while my V4 still said 'Standby'. Now, the way I was trying to connect them, I selected 'Others' on both Tamas, and then used the lower version Tama to initiate the connection. I usually do it this way because it tends to eliminate a lot of random connection bugs. However, when I tried it backwards, and used the V4 to initiate it, it would first say 'Connect', and then 'Fail' on both Tamas.

So I think what's happening is that my V4 can send IR signals fine, but can't receive any. Does anyone know how to fix this? Looking through the red plastic, the thingy looks fine. I think the problem's on the inside. Should I open it up, see if I can fix it? Or just leave it be?

Bandai's advice for fixing IR connection problems: press the reset button on the back, then from the download / reset menu on the screen, select download.

Same with my pink v4. I tried readying it but it didnt work.

Resetting*

It's possible that it's permanently busted but my stubborn V4 usually "gives in" after a couple resets. Sometimes it takes more than one reset and sometimes you gotta accept that you'll be unable to connect. You could try to replace it but I'm not knowledgeable about replacing IRs, let alone if it's possible to even replace one.