Agilent Technologies E8285A Manual page 74

Troubleshooting
Manual Troubleshooting Procedures
Swapping Known-Good Assemblies
Most swapped assemblies which use calibration data will operate well enough with
the original assembly's calibration data to troubleshoot and to run the diagnostics;
do not expect the Test Set to meet its specifications. Some assemblies may appear
to fail because of incorrect calibration data. It is also important to keep track of the
original assemblies in the Test Set. If calibration data is lost, the assembly will
have to be sent back to the factory.
Calibration data is generally stored in a daughter board's socketed EEPROM on
the digital controller assembly. If the controller is replaced or swapped, the original
EEPROM must be put in the new Test Set's controller. Should the EEPROM lose
its data, the entire instrument will require factory restoration.
The assemblies that require downloaded calibration data from a memory card are:
• Spectrum Analyzer (optional)
• Measurement
Swapping these assemblies may cause some performance specification failures if
the swapped in assembly's calibration data cannot be downloaded.
The assemblies that require on-board calibration loaded at the factory are:
• Downconverter
• Upconverter
• RF I/O
• Output Section
• Receiver
• Signal Generator Synthesizer
• Receiver Synthesizer
• Reference
Swapping these assemblies should not cause a performance problem, as their
calibration data resides with the assembly.
The assemblies that require a periodic calibration procedure are:
• CDMA Reference
• RF Input/Output
• LO IF/IQ Modulator
• Audio Analyzer 1
• Audio Analyzer 2
• Measurement
• Modulation Distribution
Generally, these assemblies can be swapped without an immediate need of
recalibration. In some cases though, a recalibration may be necessary to properly
troubleshoot the instrument.
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