Speedometer problem

[NevadaDVX]

It appears that my cable is spinning inside the back of the speedometer where it mounts inside. I assumed the cable was broke, went to Napa and got another one (about two feet longer!) and have the same results. I can disconnect the cable and spin where it mounts by hand and the needle moves, so I know the gauge itself works.

Any fix to this, or do I need another speedo? This is a white face gauge setup I bought from that guy on ebay and it has been NOTHING but a headache. So, if I change speedos, I will have to also get a set of white face stickers and pull the assembly all apart again.