NORTHROP GRUMMAN Sperry Marine NAVIGAT X MK 2, Assembly Instructions Manual

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NAVIGAT X Mk 2 056341 Rev. AA
4: Preventive Maintenance Page 4-9
4.3 Maintenance by Service Personnel
4.3.1 Gyrosphere Installation and Service
Gyrosphere installation and service are described in Chapter 8 of this manual.
4.3.2 Updating the System Software
A system software update is installed by exchanging the pre-programmed
flash-memory chip, IC 35, on the main PCB.
Parts and tools required
– a flash-memory chip, stock no. 20669, pre-programmed with the latest sys-
tem software release
– a 5 mm Allen key
– a suitable IC extractor tool (the flash-memory package is a 32-pin PLCC)
Procedure
1) Retrieve the standard manual settings, system configuration and magnetic
compass calibration tables and verify that the recorded parameters corre-
spond to the actual settings as stored in the compass' memory.
If no records have been kept, make copies of the blank forms at the back of
this manual and fill out the tables completely.
In particular, verify that the shaft encoder correction value corresponds to
the value marked on the baseplate and make sure to record the shaft en-
coder and alignment error correction values.
2) Access the Technical Pages and make notes of the temperature correction
and gyrosphere current gain values.
Warning Caution
The flash-memory chip is a static-sensitive device.
Precautions must be taken to prevent electrostatic discharge.
Caution
When the system software is updated, all parameters in the Manual Settings,
User Setup, Service Setup 1 and Technical Pages menus will be reset to their
factory defaults.
All parameters must be recorded before the old flash-memory chip is removed
and re-entered manually when the new chip has been installed.