What you need is a "schematic" diagram- that shows how the components and wiring connect. A service manual (not owners manual) will also have that. Googling "Auriol HG07890B-MSF-RX" brought up one site which seems to have just owner's manuals, but looking through that you can find info on their repair centers (phone-website-street address). The host offering manuals on that website is connected to "repair cafe" which seems to be an independent repair service. I cannot vouch for any on these sites, companies, or people as I've heard nothing of them before just now.
Alternately you may find a phone or computer repair shop who can try to find where the wire went and fix it; there should be some evidence of the old connection which their magnifiers and experience might show them. Or you could do this yourself. You do need to be quite certain of where the wire was doing it this way, because a wrong connection might destroy the unit.
Hope this helps,
Phil
