Boss RV-2 debugging help needed

[Rockmusikeren]

I have this RV-2 not working, the polarity has been reversed and the diode D2 was blown.
There is clean sound passing trough so the buffers seems to be fine and and when engaged the red led lights up just fine, but the sound is still clean with no effect whats so ever.
Could it be the switching? I hope someone can help me with this one...

Link to Schematic: http://elektrotanya.com/boss_rv-2_digital_reverb_pedal.pdf/download.html