1961 Apache speedo inop...ideas?

[Old-Soul]

Good afternoon gents,

My recently acquired '61 has something wrong with the speedo. The cable spins freely, and when hooked up to an aftermarket speedo works as it should - however, when it's hooked up to the cluster I have no speedo movement whatsoever.

I had a similar issue with my '49, however it was totally froze and hooking it up meant twisting the cable off.

Anyone else come across this?

thanks!