I bought a prebuilt stereo VPM-1 about a year ago. It’s been great. I’ve recently changed my pedalboard and hooked up the Tuner output. I’m not getting any signal. I’ve tried plugging directly out of the tuner and into an amp and wiggling the cable, nothing. I pulled the unit out of the chassis and double-checked that the jumper is in place. It is, but still no signal. Any ideas?