I've just measured the voltage at the nova-s budget cards. The voltmeter says 13.03 V so I assume this is ok. What can I check now?All the channels you have listed as not working are on vertically polarized transponders. Vertical polarization requires "low" LNB voltage (13 Volts). If your DVB card provides a voltage that's too high in that case, the switch won't deliver the vertical, but rather the horizontal signal.