Agilent Technologies 8564EC Service Manual page 250

YTO Loop Error (331)
This error rarely occurs but is usually indicative of a
digital hardware failure.
331 FREQ ACC Invalid YTO frequency. Firmware attempted to set the
YTO to a frequency outside the range of the YTO
(2.95 to 6.8107 GHz). Suspect a digital hardware
problem, such as a bad RAM on the A2 controller
assembly. Contact the factory.
600 MHz Reference Loop (333)
This error requires troubleshooting the A15 RF board
assembly (synthesizer section) or the ADC circuits.
333 600 UNLK The 600 MHz reference oscillator PLL is unlocked. If
error codes 302, 303, 304, 327 or 499 are also present,
suspect the 10 MHz reference, the A21 OCXO, or the
TCXO (Option 103), or the A15 RF assembly. ERR 333
is set if LO3ERR is outside of its prescribed limits.
Sampling Oscillator (335)
This error indicates an unlocked sampling oscillator
(also known as the offset lock loop).
335 SMP UNLK Sampling oscillator PLL is unlocked. ERR 335 is set if
OFL_ERR is outside its prescribed limits.
10 MHz Reference (336)
This message occurs during the internal IF calibration
routines. The routine locks the cal oscillator to the
internal 10 MHz reference, regardless of the setting of
INT/EXT REF.
336 10 MHz Ref Calibration oscillator failed to lock within 5 seconds
after going to internal 10 MHz reference. ERR 336 will
not be cleared until a successful full calibration "LO
Re-Align" is executed.
Fractional N PLL (337)
This error indicates an unlocked fractional N phase
locked loop. This error only applies to the hardware in
an 8560 E-series or EC-series spectrum analyzer.
337 FN UNLK Fractional N circuitry is unable to lock.
Chapter 7
General Troubleshooting
Error Messages
331