Here is some advice from the HP 9830 service manual. It contains
Can't be! The 9830 tape drive and cassette are very different to those
used in the 9825. The 9825, as we all know by now, uses a tape driven by
an endless belt in the cartridge. The 9830 uses tapes with the same form
factor as audio compact cassettes. The 9830 tape drive has 2 motors which
drive the 2 spools, with a pair of solenoids to engage the drive. There
is no capstan or pinch roller.
-tony