This is just a quick one... I don't have any diagram or schemes for the Compact, so i found this out only by coincidence. Vibrato was dead so I unsoldered and re-soldered a few things and - bingo - found the relevant thing:
(click on the pic to enlarge)
Check the circled spot. Is the red wire loose? Re-solder it! If it's not, try unsoldering and then re-soldering.