if your master output or other outputs dont work, congratulation one "IC" is defect...
i run in this failure on the day as i sold this device on ebay, but i repaired it by unsolder/solder the very small SOIC format IC...
i dont documented it here due to the high risk, that a DIY beginner try to desolder the part..
the part can only be swapped by a professional SMD technican - otherwise you destroy the mainboard
Extend a Supernova2 from 24 to 48voices.
Disconnect power and all other cables (midi, audio etc.)
on the left and right sides of the chassis disconnect the screws ( every side 1 screw)
now you can lift up from the keyboard side .
you can find the main pcb on the left side, find the 2 pcb plastic holder.
yet you have to push the voicecard downwards (voice card pcb holes in the mainboard pcb stands)
Attached Voicecard 2-3cm on the left from the ribbon cable
At the left side , you can see the attached voice card