Harmonic Technology Magic Link soldering issues

Thinking I wanted to upgrade my HT Pro Silway IIs, I purchased two sets of used HT Magic Link IIs from two separate sellers. I put them into service and could immediately hear the difference.  After a while I started having problems with hum.  After searching hi and low, I found the problems to be detached solder connections that had been holding the negative connections to the terminals casings.  Both sets had the same problems.  As with other HT cables, there is no lug for the ground wires, they are just soldered to the casing.  My Pro Siway IIs seem to be better made as they have not detached after years of use.  I re-soldered them the best I could, but know they will probably come undone again.

I was just wondering if anyone else had had this problem with their HT cables?  I’m thinking re-termination is the best solution.  I have done it before, but it was messy as I am not a great solderer.  Any suggestions?  Thanks.