so i found a manual for a small HV device, using a flyback, powered by DC supply. here's the link for the http://tacashi.tripod.com/elctrncs/555sstc/555sstc.htm" [Broken] i built a small platform giving the primary coil 8V in frequency which in theory should be around 20 KHz(i do not have an osciloscope, but i have a resistor trimmer, so i can scan the frequencies). but for some reason, the secondary coil produces very little voltage, it vibrates, and it make a spark at about a milimiter gap, so i know that there is induction going on, but very little. i have a suspition that it has to do with the flyback itself, because its of an old screen from 1988 5 inch, monocrome. so please do tell me what could be wrong?