Getting an incorrect RPM readout on a Turbo T-60S Lathe? This can be caused by a few different things related to the RPM sensor located inside the unit behind the switch plate.
Here is a link to a video that explains the cause of the RPM indicator not registering the correct RPM and instead is displaying a 0 or possibly a 1 if it is occasionally activating the sensor rather than for each revolution.
Depending on the current state of the spindle's magnet and sensor location, you may have to make an adjustment to the bracket, or the sensor and in some cases, the magnet, to get the magnet on the spindle to line up with the sensor and register each revolution correctly.
If you have confirmed that the sensor is activating on each rotation and the bracket is installed properly in alignment with the magnet on the spindle, and the problem persists, check the wiring that runs from the sensor to the screen. If the wiring is loose, the screen will not register the sensor and this problem could be fixed by ensuring the wiring is connected to the back of the screen or replacing the screen if necessary.