Vaisala GMW90 - Manual (Page 71)

Chapter 5 _______________________________________________________________ Maintenance
VAISALA ________________________________________________________________________ 69
Repair Maintenance
If you cannot restore the measurement accuracy of the transmitter by
calibration and adjustment, you can replace the measurement modules
inside the transmitter. Measurement modules are the small component
boards that are connected to the main transmitter component board. See
Figure 4 on page 17.
NOTE User calibration settings (adjustment by trimmers or service port) are
stored in the module. If you replace the module, you do not need to undo
the previously applied correction.