How can I remove offsets on a Instanel® Series III monitor?


To fix an offset problem on the Instanel® Blastmate III™ or Minimate Plus™, please follow the instructions below:

  1. Ensure you are in a quiet area with low vibrations.
  2. Turn on the Instantel Minimate Plus or Blastmate III.
  3. Connect the Geophone and Microphone (Linear only).
  4. Press the Test key.
  5. Wait until the results of the Sensor Check appear.
  6. Simultaneously press the Start Monitor and Option keys.
  7. The message, "Performing Autozero" will appear on the display.
  8. Press the Enter key.
  9. Ensure that the sensors are properly connected, and press the Enter key.
  10. Wait for unit to perform the Autozero function. 
  11. Press the Enter ​key twice.

You will now be at the Main Menu, Ready To Monitor state with the offset problem corrected. 


When you perform an Autozero on any Series III units, the list of numbers in the X1 and X8 gains should all be between 2027 and 2069. If not, you will need to repeat the Autozero process. If the numbers are extremely out of the specified range, then the unit should be sent in for repair.
If this process does not remove the offset problem, then you will need to return the unit and sensors back to Instantel for repair