currently using 3b2 version 7 very successfully, but need to upgrade hardware and have
to change the old dongle to a usb version, anybody got any ideas
I suspect you don't have active maintenance with PTC, so you're probably going to need to buy a USB-to-parallel port adapter for the new machine.
I would suspect driver issues, either with the USB device drivers, or with the Sentinel drivers. You may have to install a newer version of the Sentinel drivers than what shipped with 3B2 v7.
To our understanding PTC are now again offering parallel to USB dongle exchange, if you wanted me to send you the form for that please let me know.
If you don't want to pay the charges for this, i know of a customer who successfully used dongle emulator software or if not there have been links and comments about dongle adapters on the 3B2users yahoo group over the years so might be worth a search there.