Nie musi szukać elektronika, ktoś to już pomierzył.

I just took a voltage check on my Vivitar. It's scary. Anywhere from 155 vdc to 165 vdc. Anybody with an electronic type camera is looking for trouble if they don't know what there camera can stand. I had it working with my old Yashica FX-3.
Źródło: What is the voltage on old Vivitar 2800 auto thyristor flash? Will it work with Canon Rebel? - Photo.net Accessories - Filters, Bags, Tripods Forum

Tu inny model z jeszcze bardziej hardcore'owym napięciem:

Taming the high trigger voltage of the Vivitar 283

Dlatego katara3 lepiej nie używaj tego Vivitara 2800 ze swoim EOS 1000D.