The Sunpak 555 is a thryristor unit can be adapted to the electronics of film slrs on those machines that have those capabilities. I would not have considered using an old Strobonar or Metz potato masher on that circuitry. As of this morning (ca 14 hours after the shoot) the Nikdon D50 dighithell camera is still working. Thanks, again, to the advice I have received.