Checking the Motor Speed on a 390/391

Users may encounter reading errors that could be caused by a motor speed that is too high or too low.  Sometimes the motor can go bad and either cause read errors or, in some cases, fail to pull that strips thru at all. 

If an X-Rite 390/391 scanning densitometer is failing to successfully read an acceptable film control strip or calibration strip, the motor speed should be checked.  A motor that is running too slow, fast, or inconsistently can cause read errors. 

The motor speed on a 390/391 densitometer should be between 1.0 - 1.4.  The numbers should be the same or consecutive (+/- .01) to ensure that the motor speed is consistent.  If the number doesn't fall within that tolerance on an 390 series unit you can use the POT keys (two middle buttons) to try to adjust the motor speed.  The user can also run the "mot" test 3 to 4 times to force motor calibration.  If the motor speed is not able to run within tolerances, the unit would need service.

Please use the following steps to check the motor speed on these densitometers:

  1. Go to the "MAIN MENU" by selecting the two [MENU] keys (the two buttons on the right).
  2. Press [p1] and then select [p2] to go to "p3".
  3. While in "p3", tap the two middle buttons to access the "BIT MENU" and then select [mot].
  4. The motor speed will display two values (i.e., 1.1 > 1.1).  Select [exit] to return to the "BIT MENU".  Repeating this step three or four times can sometimes correct a motor speed that is not within the +/- .01 tolerance. 
  5. If the motor speed is lower than 1.0 or higher than 1.4, the user can use the [POT] keys (two middle keys) to increase or decrease the motor speed and then [exit].  Select [mot] once again to check the new motor speed.  If there is no [POT] option in the display, the densitometer will need to be returned to X-Rite to adjust motor speed.
  6. Press the [exit] button to exit to the "BIT MENU" and then tap both [MENU] buttons to return to the "MAIN MENU".

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