[R-390] Small cables

[Gordon]

Where can I buy the little cables inside the 390A that have ends that 
look like miniature BNC connectors ?
I need the one that goes from the IF board J514 to the port on the back 
panel J116.
Also, is it normal for some of the tubes to be missing their shields?
I noticed the Ballast tube on the IF board and V509 on the IF board are 
both missing the shields.
I just purchased my first R-390A and want to be sure I have all the 
right pieces before I start to restore it.

thanks,
Gordon
N6WK