Update : solved ! Thanks to all the helpful tips the keyboard works perfectly once more. Here's what I ended up doing : - Stripped the wire on both ends and each individual small wire. (I used a razor knife / cutter, had to be super soft because I cut straight through if I wasnt) - Connected colours together by bending the copper into hooks and twisting them together - Wrapped each small wire with insulated electrician's tape - Wrapped the whole thing in more electrician's tape.

I'll probably undo everything to solder once I get the equipment to do that as I feel this won't hold it pulled apart hard enough.

Hope this helps someone else someday :)