Setup the new system and terminal (I've already go a VT420 but a VT520 came with it) and booted the new system and checked that I could get into the OS.
The guy I bought it from had kindly provided the login details so I had a poke around to see that everything was ok. Apart from the network not being connected everything seems to boot and start up fine.
Next stop is to install a clean OS.
Backing Up System
Started off looking to backup both the new and other VAX box using one of the tape drives that are installed on my other VAX.
And the newer TLZ06...
Ordered some CompacTape cartridges but have managed to get the CompacTape III ones instead of the earlier version, these don't fit into the TZ30 drive so I instead ordered some new DDS-90 tapes for use in the TLZ06.
Now waiting for them from eBay.