I have a motherboard with a defective PS/2 port. When the connector is inserted it doesn't grip it correctly and causes the system to beep endlessly. Booting without a keyboard connected does not cause this problem.

I have tried several times to boot by adding various amounts of pressure and only once would it boot without the error beeps. But as soon as I removed the pressure it would sag and started beeping again.

The solder joints on the bottom of the board look fine with the connector itself appearing extremely worn. I don't know what the exact problem is but I would guess that replacing the entire thing might fix it.

I had trouble finding a source for these with prices as high as $10 USD for a single connector. I finally found a source on Aliexpress for about $8 USB for 10 pieces and this seems to be a very good price.

https://www.aliexpress.com/item/32773347439.html