Some keyboard keys work and stop randomly

Hello,

I have a newer model on Dell Inspiron 3520 (purchased in 2023), and several keys stopped working:

• keys: Z, X, C, V, M, , , ., Enter, 5, 6
• Sometimes they worked if I start continuously pressing that key hard or didn’t move the laptop, but now they almost never work.
• There has never been any water damage on the laptop.
• In the BIOS diagnostic test, these keys also fail (so I believe it’s definitely not a Windows/Linux driver issue).
• If the keys stop responding completely, I sometimes have to do a kind of “ritual”: pressing Z, X, C, etc. (that whole line) hard, several times in a row. After that, they may start working again for a while , but not properly.
• After a restart, they occasionally come back for a short time, but the problem always returns.

I’ve never seen a keyboard problem behave like this. If the keyboard trace was physically broken, I would expect the keys to stop working completely but here they randomly start and stop working.

Before I replace the entire keyboard, I’d like to pinpoint the exact cause and be sure I’ve tried everything (I also want to avoid adding unnecessary e-waste).