Hello.
About the DC300 cassette repair: I have a lot of these cassettes,
original from DEC with standalone backups of software for VAX 730 inside.
Unfortunately all of them suffer of the "sticky" problem, the tension band
attached to the tape, and then broke itself.
A replacement of the bands is surely needed, the plastibands maybe
could be a good source.
The problem of the stickness remains however: how could I detach the
tension tape from the magnetic tape without peel off the magnetic substrate?
Maybe opening the cassette, adding some lubricant without solvent (silicon
oil for example) and leaving it for some days could help?
Andrea