Mach3 Lathe Threading Struggles

[mondrota]

Okay I think I found the problem (or a symptom) but I still need the cure :)
So I noticed that on the turn diagnostics screen the "Locked RPM" and "current RPM Variation" read 0 and "Highest Variation during thread" reads 1% when the Spindle Feedback is disabled. This is when the program will run the threading but with poor results.
However, when the Spindle feedback is enabled, all of the above fields on the diagnostic screen read " 1.#INF "
Please have a look at the attached picture.
For some reason I can't attach the other one with the fields reading the " 1.#INF "

I have a feeling that for some reason mach3 cant syncthe threading to the spindle speed.
I found a thread describing the same problem here:
http://www.machsupport.com/forum/ind...79.0/wap2.html
The person having this problem managed to sort it out just by fiddling with the sensor wiring. I've tried rerouting the wires but to no avail. Is there anything else that would cause the syncinc to fail?

Many thanks!