Well I’d start by turning it off, and unplugging it! which I imagine you did. I would then disconnect everything connected to it. Then take it out of what ever it’s in or on, put it on a kitchen table so you can inspect etc then following your owners manual check the fuses. If they are good put them back in and reinstall the SN2, connect everything back up and test. if the left channel is still acting up. Turn it off and send it or take it for service.
How old is the unit? is it under warranty? sounds like the left channel pooped the bed… sorry sounds like the left channel has failed. any storms in your area last night?Any burning smells from the unit? If not much else I can think of to check… Good luck
When you say that neither the balance or volume work, do you mean you get no sound? If a full power off, rest and then on again, doesn’t clear it then it does sound like it probably needs to be seen by a Naim technician. I would give your dealer or distributor a call this morning.
Yes, there is definitely something wrong in the gain stage of the preamp or the power amp stage.
I would suggest not connecting speakers to it until it can be rectified.
It sounds like a transistor fault, but could also be a polystyrene capacitor.