i have zvs flyback driver and taking up to 2000 voltage on secondary side with around 100 turns on secondary coil . no any problem
but something strange happening , if i add more turn ( in order to get higher voltage ) on secondary winding ( above 100 turns , ie 300 turn ) there is absolutely no voltage on secondary side although good oscillation and good voltage on primary .

core is ferrite from old CRT tv and i rewinded , i also have tested on sendust toroidal core , but same

pls advise , what is going wrongly

 

Schematics and pictures please.

 

Schematics and pictures please.

pls see pictures , it is chinese ZVS driver , Schematics is exactly Mazilli driver , 2 chokes 130 uh, 0.66 uf capacitor , 2 pieces 470 ohm , other 2 pieces of resistor 5.2 kohm . irfp260 mosfets
oscilloscope shows Pi ( 3.14 ) x Vin on primary and frequency

but no any voltage on secondary while voltage oscillates on primary
wires are ok , shown 15 om resistance
no idea whats wrong ,

 

It may be that when you add more tuns you connect to the secondary with the wrong polarity. Flyback supplies are polarity sensitive.