Lo And Rf Hardware/Firmware Failures (300 To 399); Yto Loop Errors (300 To 301); Roller Pll Errors (302 To 316) - HP 8560A Service Manual

LO and RF Hardware/Firmware Failures (300 to 399)

YTO Loop Errors (300 to 301)

300 YTO UNLK
301 YTO UNLK

Roller PLL Errors (302 to 316)

302 OFF UNLK
sweep and, if the voltage is outside certain limits, the offset oscillator
pretuned DAC is adjusted to bring OFFSENSE within the proper
range. ERR 302 is set if this cannot be accomplished.
303 XFR UNLK
Transfer roller oscillator PLL is unlocked. May indicate loss of
than -7 dBm at A155303. The ADC measures XFRSENSE at
the beginning of each sweep and, if the voltage is outside certain
limits, the transfer oscillator pretuned DAC is adjusted to bring
XFRSENSE within the proper range. ERR 303 is set if this cannot be
accomplished.
304 ROL UNLK Main roller oscillator PLL is unlocked. May indicate loss of 10 MHz
reference. The 10 MHz reference should measure greater than -7 dBm
at A15J303. The ADC measures MAINSENSE at the beginning of
each sweep and, if the voltage is outside certain limits, the main roller
pretune DAC is adjusted to bring OFFSENSE within the proper
range. ERR 304 is set if this cannot be accomplished.
305 FREQ ACC Unable to adjust MAINSENSE close to 0 volts using the coarse adjust
DAC. The coarse adjust and fine adjust DAC are used together to set
MAINSENSE to 0 volts with the loop opened. ERR 305 is set if the
coarse adjust DAC cannot bring MAINSENSE close enough to 0 volts
for the fine adjust DAC to bring MAINSENSE to exactly 0 volts.
306 FREQ ACC Unable to adjust MAINSENSE to 0 volts using the fine adjust DAC.
The coarse adjust and fine adjust DAC are used together to set
MAINSENSE to 0 volts with the loop opened. ERR 306 is set if the
fine adjust DAC cannot bring MAINSENSE to 0 volts.
6-18 General Troubleshooting
These errors often require troubleshooting the Al4 Frequency Control
assembly (Synthesizer Section) or the ADC circuits.
YTO (1st LO) L oo is unlocked. The ADC measures YTO-ERR p
voltage under phase-lock condition.
YTO Loop is unlocked. Same as ERR 300 except ERR 301 is set if
the voltage is outside certain limits.
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 present,
suspect the 10 MHz Reference, the A21 OCXO, or on the Al5
assembly (Option 103).
Offset roller oscillator PLL is unlocked. May indicate loss of 10 MHz
reference. The 10 MHz reference should measure greater than -7 dBm
at A15J303. The ADC measures OFFSENSE at the beginning of each
10 MHz reference. The 10 MHz reference should measure greater