HP 8560A

315 FREQ ACC
316 FREQ ACC
Indicates problems in the span calibration. Troubleshoot any unlocks
before attempting to troubleshoot span calibration problems, because
the loops must all lock in order to perform the calibration. If LO
spans greater than 1 MHz are correct, check A14U114B , A14U115A,
A14U116, or A14QlOl. This error message appears when the roller
Span Attenuator DAC is out of range. This DAC value is recalculated
each time there are changes to the span or start frequency. ERR 315
is set if this value is less than 10 or greater than 245.
Sensitivity of main roller pretune DAC is 0. Once the main roller is
locked, the MAINSENSE voltage is measured and the pretune DAC
value is incremented by two. ERR 316 is set if the difference between
the new MAINSENSE voltage and the previous MAINSENSE voltage
is 0.
YTO Loop Errors (317 to 318)
317 FREQ ACC
These messages indicate that the YTO Main Coil Coarse DAC (ERR
317) or fine DAC (ERR 318) is at its limit. If error codes 300 or 301
are not present, a hardware problem exists in the YTO loop but the
loop can still acquire lock. Refer to Chapter 10 to troubleshoot the
YTO PLL. The ADC circuit on the A3 Interface assembly may also
cause this error.
Main coil coarse DAC at limit. The main coil coarse DAC is set to
bring YTO ERR close enough to 0 volts for the main coil fine DAC to
bring YTO ERR to exactly 0 volts. ERR 317 is set if the main coil
coarse DAC is set to one of its limits before bringing YTO ERR close
enough to 0 volts.
318 FREQ ACC Main coil fine DAC at limit. The main coil fine DAC is set to bring
YTO ERR to 0 volts after the main coil coarse DAC has brought
YTO ERR close to 0 volts. ERR 318 is set if the main coil fine DAC
is set to one of its limits before bringing YTO ERR to 0 volts.
Roller Oscillator Errors (321 to 329)
321 FREQ ACC
322 FREQ ACC
These errors indicate a faulty roller oscillator on the Al4 Frequency
Control assembly. Refer to Chapter 10. The A3 Interface ADC
circuits may also be faulty. If error codes 333 and 499 are also present,
suspect the 10 MHz Reference, the A21 OCXO, or the Al5 assembly
(Option 103).
Main roller tuning sensitivity is not greater than 0. The MAINSENSE
voltage is noted in a locked condition and the main roller is
programmed to a frequency 400 kHz higher. ERR 321 is set if the new
MAINSENSE voltage is not greater than the previous MAINSENSE
voltage.
Main roller pretune DAC value set greater than 255. During the LO
adjust sequence, the main roller is locked and then programmed to a
frequency 1.6 MHz higher. A new pretune DAC value is calculated
based upon the main roller tuning sensitivity. ERR 322 is set if this
calculated value is greater than 255.
8-20 General Troubleshooting