I've had this happen umpteen times and it was always down to me having moved my dish and not checking the configuration correctly....but I would try what urie has suggested first of all...I dont believe it's possible to change the tuners on these boxes....
QuoteDoes anyone know whether I can confirm that the DVB-S2 tuners have broken, rather than being misconfigured?
I've just taken the STB apart and it looks like the Tuners are soldered to the mainboard :( so a DIY repair is out of the question.
Have you double checked you tuner selection in case they are set to wrong one. Also machine may still be under warranty.
I've tried everything under tuner selection, many, many times. The box was under warranty when this first started happening but I didn't report it in time.