Can a 285 hv vivitar be used on a nikon d70?
It depends upon he trigger voltage of the flash unit.
Check with the manufacturer for the specs to be sure; older units may be different from the newer ones. CYA!
There is an ever growing database of flash voltage information at
Voltages can be safely dropped with the Wein SafeSync, though I have not personally tried it. It has a good reputation, but I rarely use flash.