My son messed with the settings and the unit now has audio only, no
picture. Does anyone know the factory reset procedure? When I plug it
in while holding STOP and PLAY on the device, it shows N3320U in the
display. Pressing menu repeatedly brings up various codes, then all
the LED elements on, then CHCK but nothing about reset.

I tried leaving it unplugged for several days now, but no change.

Thank you for reading.

Regards,

Yimin