SK-1 lights up, no sound

[Smitty D]

My SK-1 was fine warming up for practice. I switched it off till the band arrived. upon turning it back on, it lit up but i had no sound whatsoever.
I made sure control was on keyboard and did a few factory resets. Still nothing. I hear a pop as soon as I press any note key.
any suggestions?

 

[Stampanator]

Id try and see what midi is coming out of it. Could it be set to local off? Ie its expecting midi externally?