Hi Darren,
I my experience 9 times out of 10 when this type of problem arises with Ultrasound machines it is not an issue with the machine. It is likely to be one of the following(sorry if you have already tried these!).
Check the network port on the wall where the machine is plugged into, always try another network port, which is on the pacs network or VLAN(unless IT uses port security-please check this first). Use a known good network cable. Check with IT and the Pacs Manager that there are no problems currently with the Pacs and the Worklist servers. Ask them to ping the BK Scanner from their workstations. Happy to help further if you require anymore advise.