DOD FX25B troubleshooting

Howdy!

I picked up a decent looking Envelope Filter yesterday at a flea market for $5. The guy didn't know if it worked so I thought for that cheap what the heck.

Got it and home and it powered up, though no effect. Signal passes through when on or bypassed, and there's a slight tonal change when turning the blend to full wet. The other controls have no effect on the sound.

I've attached a picture of the only thing I noticed: the R34 resistor is toast. Would replacing this solve the mystery?