Agilent Technologies 856290216 MHz Reference Loop, YTO Leveling Loop, Sampling Oscillator

600 MHz Reference Loop (333)

This error requires troubleshooting the Al5 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 Al5 RF assembly. ERR 333 is set if LOSERR is outside of its prescribed limits.

YTO Leveling Loop (334)

This error often requires troubleshooting the Al4 frequency control assembly (synthesizer section), the A7 LO distribution amplifier, or the ADC circuits.

334 LO AMPL First LO distribution amplifier is unleveled. Error 334 may be displayed if the front-panel LO OUTPUT is not terminated in 50 0. This error is usually accompanied by error codes 300 or 301. ERR

301 YTO UNLK is cleared once ERR 334 has been cleared. Check the output of the All YTO with the jumper on A14J23 in the TEST position. The YTO power output should be between +9 and +13 dBm. If the YTO is working properly, refer to “LODA Drive” under “Al4 Frequency Control Assembly,” in Chapter 12, “RF Section.” The LODA AGC voltage is monitored by the ADC. ERR 334 is set if LODA AGC is outside of its prescribed limits. Refer to “LODA Drive” under “Al4 Frequency Control Assembly,” in Chapter 12, “RF Section.”

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 cal “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 HP 8560 E-Series spectrum analyzer.

337 FN UNLK Fractional N circuitry is unable to lock.

7-26 General Troubleshooting