Fix music player's sound management

Zefram

2014-08-14 1d0687556a52891aeadc0e8d9a58e44c53cb826b

 technic/machines/MV/battery_box.lua

@@ -16,5 +16,7 @@
   discharge_rate = 80000,
   charge_step    = 2000,
   discharge_step = 8000,
   upgrade        = 1,
   tube           = 1,
})