Originally Posted by
Eldon_Joh
did you burn out the 50 watt transformer?
if you can verify the 100 watt flyback has the same turns ratio, you may be able to change the air gap of the core so that they both have the same inductance. but if the 50 watt is burned out then you can't measure its inductance.
it would take some signficant reverse engineering to subsitute a different transformer into a flyback converter, it may not be worth your time to do so. you risk messing up the control loop of the power supply as well as burning out the switch (which is likely a 500 +volt mosfet but it could be a 500-900 volt transistor or a high voltage igbt)
the flyback control loop in your case probably works by waiting until the current exceeds a given value and then it turns off the switch. subsituting a larger transformer (which may have much lower inductance) will require a higher current capacity in the switch, and in order to make it work you may have to change the current sense resistor for a lower value.