Agilent Technologies 856290216 Automatic Fault Isolation References, Synthesizer Section

Table 11-2. Automatic Fault Isolation References

Suspected Circuit Indicated by Automatic Fault Isolation

Check the YTO loop

Check first LO

Check first LO pretune frequency and amplitude Check the fractional N oscillator

Check 3rd LO drive

Check 10 MHz reference to phase/frequency detector

Check for 10 MHz signal at other input to phase/frequency detector

Check A3 ADC MUX function block

Check Al4 frequency control assembly

Check A14J301 10 MHz REF input

Check Al5 RF assembly

Check current source U307

Check FM loop sense

Check YTF gain and offset DACs

Check level at amplifier Input

Check levels into mixer U400

Check loop references

Check main coil tune DAC

Check main coil coarse and fine DACs

Manual Procedure to Perform

Confirming a Faulty Synthesizer Section

(steps 12-33)

Confirming a Faulty Synthesizer Section

(steps 9-11)

Unlocked YTO PLL (steps 9-12)Unlocked YTO PLL (steps 13-17)Third LO Driver Amplifier (steps l-6)Unlocked Reference PLL (steps d-13)

Unlocked Reference PLL (steps 12 and 13)

Confirming a Faulty Synthesizer Section

(steps 1-d)

Confirming a Faulty Synthesizer Section

(steps 12-18)

Confirming a Faulty Synthesizer Section

(steps 5-8)

Confirming a Faulty Synthesizer Section

(steps 18-25)

First LO Span Problems (All Spans) (steps 14-21)Unlocked YTO PLL (steps 27-34)

YTF Driver Circuit (steps 10-23)Third LO Driver Amplifier (steps l-6)Unlocked Offset PLL (steps 3-13)Unlocked Offset PLL (steps 1 and 2) Unlocked YTO PLL (steps 45-49)Unlocked YTO PLL (steps 41-44)

1 l-4 Synthesizer Section