I haven't run into anything like this before. It appears to be a huge non-polarized capacitor, but the rating is strange. 3VNP 1.0 ohm 60 Hz. Would that be 3 volts non-polarized with an impedance of 1 ohm @ 60 Hz ?
I plugged 60 Hz and 1 ohm impedance into
this site and came up with 2.65258 mF (about 2,650 uF)

:
Any thoughts on what to use for a replacement ?
Mouser has some
2,200uF non-polarized caps. Maybe that's close enough ?
It's C4 in the schematic.