DL360 G5 RBSU keys

[KevB8376]

I have a pair of DL360 G5's that I'm having a mare with. When entering the RBSU, neither will let me scroll or select anything. I have tried multiple keyboards of both PS/2 and USB but no joy. The keyboards do work however as I can press F9 to select RBSU and Ctrl Alt Del to reboot but besides that, nothing. They work on other machines, so I'm inclined to say they aren't at fault. 

Am I missing something really obvious?

[Jimmy Vance]

You might try resetting NVRAM using switch 6 on the system board.

Power off
Switch 6 ON
Power on,  (I don't recall if a G5 displays a message that system has been reset or not, if not leave powered on for a few minutes)

Power off
Switch 6 off
Power on and see if your keboard works

[KevB8376]

Unfortunately no, doesn't resolve it. It's really strange, it's as if it's freezing. Only keyboard input that it accepts on entering RBSU is Ctrl Alt Del. 

Further and possibly connected, booting from any media (optical or USB) they detect whatever is on but then go no further. 

I'm beginning to doubt the assurances of being "tested working ok"