Hi, I have the same problem with a 35s. The funny thing is that last week while testing, it started working normally for about an hour and then stopped. I think that it could either be a bad contact or something is obstructing the needle movement. I also tried it with a mercury cell to see if something would change but no, same thing.
I've searched the net but I didn't find anything useful.
Let me know if you find something.
Khaled