[edit: see last post below, this is now fixed]
The mixer console on the shelf above the stim computer has a malfunctioning knob (see picture below) that can cause the right channel volume to drop by a lot or completely. I’ll look into fixing this, but for now, if it happens, you can turn the knob up-down a few times to “clean” the contact and restore the volume. These gain knobs are usually set to point directly up, at the middle of their range.
