Agilent Technologies 85032B/E 50 Specifiche Scaricare il pdf (Pagina 164)

Troubleshooting and Block Diagrams 8712ET/ES and 8714ET/ES

Category 2 Failures: No Error Messages but One or More Measurements Are Nonfunctional RF Network Analyzers

4-22 Service Guide

Symptom 4: R and R* Traces Are Always Below −10 dBm or Noisy

If other traces are normal, something in the R signal path could be damaged.

1. Check the power out of the coupled port on the R coupler.

a. If the power level is below −20 dBm, replace the R coupler (refer to “Removing the

Coupler” on page 3-15).

b. If the power level is above −20 dBm, replace the receiver PC board from the receiver

assembly (A5). (Refer to “Removing the Receiver PC Board” on page 3-14.)

Symptom 5: If the R and R* Traces Are Normal, while A, B and B* Traces Are Always Below −10 dBm

This failure indicates that there is a power interruption after the R coupler.

1. Replace the A coupler (refer to “Removing the Coupler” on page 3-15).

2. If the problem persists and the analyzer is an Option 1E1, replace the attenuator (refer

to “Removing the Attenuator (ES and Option 1E1 Analyzers)” on page 3-16).

Symptom 6: B and B* Traces Are Always Below −10 dBm and/or Are Always Noisy

This failure indicates a problem after the A coupler.

1. First check that the thru cable is not damaged and that it is transferring the signal.

2. If the cable is good, replace the B limiter (refer to “Removing the Limiter (ET

Analyzers)” on page 3-18).

3. If the problem persists, replace the receiver PC board from the receiver assembly (A5).

(Refer to “Removing the Receiver PC Board” on page 3-14.)

Symptom 7: A Trace Is Always Below −10 dBm and/or Is Always Noisy

If other inputs are normal, something in the A signal path could be damaged.

1. The most likely failure is the coupled port in the A coupler. Measure the signal output

level at the coupled port with the RF OUT port open. The signal level should be above

−20 dBm. If the signal level is below −20 dBm, replace the A coupler (refer to “Removing

the Coupler” on page 3-15).

2. If the problem persists, replace the receiver PC board from the receiver assembly (A5).

(Refer to “Removing the Receiver PC Board” on page 3-14.)

Symptom 8: R Trace Is Normal and R* Trace is Noisy OR the R Trace Is Noisy and the R* Trace Is Normal

This failure can be isolated to the R or R* detectors and points to the receiver PC board in

receiver assembly (A5).

1. Replace the receiver PC board from the receiver assembly (A5). (Refer to “Removing the

Receiver PC Board” on page 3-14.)

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Agilent Technologies 85032B/E 50 Specifiche Pagina 164