Is there a cable that's compatible with the old Vivitar 283 strobe?
The connector on the BP-960 is the same as on the Quantum Turbo's (the larger Quantum batteries). I see the Vivitar HPV-1 battery was 510V. I thought I read somewhere that the Quantum Turbo's and BP-960 were something like 300V or 360V. I just measured 322V at the end of the Canon connector with 3 out of 4 "fuel" lights illuminated my the BP-960.
Maybe a Lumidyne or Quantum cable works from a fit standpoint, like one of these (search under "flash / batteries", but be careful on which battery they are for: