I have a vivitar 1900 but it doesn´t trigger, I buy it from second hand market so I don´t really know what could happen to it, any help will be nice, thanks to all.

 

Those things contains high voltage circuitry. If you dunno what you are doing, you should trash it or return it.

 

I do not suggest trashing it just because you cant make it work. FIRST get the instruction book, THEN READ the instruction book and know how to make it work.
I have a very nice lab power supply given away to me because it did not work. I read the book, and saw how to set the knobs to make it work. It works well if I set the over-voltage limit above zero. THAT was the only thing wrong with it.

 

Have a look at some of these camera flash circuits with explanations.

https://www.physicsforums.com/threads/camera-flash-circuit-explanation.622676/