When disconnected the needle reads 0. When I spin the cable input the needle goes up and returns to 0.
Sounds like your head is sticking. I used some WD 40 to get it to spin freely.

1954 Chevy Half-Ton
In the Stovebolt Gallery
More pix on Shutterfly
More pix on Photobucket

1958 Chevy 1/2-Ton Stepside
In the Stovebolt Gallery
More pix on Photobucket

<> + <> + <> + <> + <>
"Time's fun when you're having flies." ~~ OLD FROG