Korg DW8000, Mono/Poly, MS-20...

must have died over the weekend, might be in a coma

it boots up correctly but at maximum volume on instrument & amp I get
a lot of percussive white noise on the keys  and very soft correct
sounds on some (higher frequency) but not all patches

Are there any internal fuses or on the board fuses?

Or can I assume that the internal amp &/or some low voltage filters
got fried?  

Is there a schematic of the circuit board available?   one printed on
an inside panel?

Circuit Boards available?

My amp fixing guy is pretty good.

thanks JD