Its all about trigger voltage Andy.
My Nikon SB80-DX trigger voltage is 4.89volts, Metz 45CL3 15.5volts, and the ancient Vivitar 283 a whopping 275volts
.
So with any older kit it is worth measuring that with a multimeter before attaching to a modern camera. Different manufacturers give different max voltages for this, but as a general rule 6volt is about max for a modern camera.
To measure the trigger voltage, power the flash up and measure the volts across the centre terminal, and the ground terminal which is to the side of the hotshoe mounting.
Don