| br>First I'd say if you have a factory build, just contact Mutable Instruments and they would likely repair or replace it.
But, if you wanted to try to fix it:
This is the schematic for Links
Attached is an image of the relevant part of the schematic, as well as red circles on images of the PCB front and back of where to test. I would start with the leg of the jack and work backwards from there (Jack, both sides of resistor R2, pins 8 or 9 of the OpAmp (which are connected).