Erroneous Results; Blank Display (8560E Only); Automatic Fault Isolation - HP 8560E Service Manual

General Troubleshooting
Using the TAM

Erroneous Results

If the TAM manual probe troubleshooting seems to be giving erroneous
results, its performance can be checked by placing the probe on the
TAM test connector (A2J11) located on the A2 controller assembly and
executing the manual probe diagnostics. If either of the tests fail, the
TAM is malfunctioning and should be serviced.

Blank Display (8560E only)

It is possible to use TAM manual probe troubleshooting without a
display, if an HP-IB printer is available. Refer to Chapter 12 for more
information.

Automatic Fault Isolation

Automatic fault isolation (AFI) is designed to isolate most faults to one
or two assemblies. AFI can be run with the spectrum analyzer cover in
place, and requires only the CAL OUTPUT signal as a stimulus. The
entire procedure takes less than 2 minutes to complete if no failures are
found.
AFI performs checks of five functional areas in a pre-defined sequence.
The sequence minimizes the chance of making false assumptions. The
TAM checks the spectrum analyzer "from the inside out." For example,
the ADC is checked before the IF is checked. This ensures that if no
signal is detected through the IF, the fault is in the IF section and not a
faulty ADC. (The ADC measures the video signal from the IF section.)
The sequence of checks is as follows:
1. Controller check
2. ADC/interface check
3. IF/LOG check
4. LO control check
5. RF low band check
Display/Power Supply
AFI cannot check the display/power-supply section because this section
powers the TAM and provides the display of AFI results.
(8560E only)
Controller Check
The TAM performs a checksum of all ROMs, RAMs, and the EEROM.
The CPU is also checked, since parts of the CPU could be nonfunctional
while the TAM still operates. These checks are very similar to those
done by the spectrum analyzer at power-on.
294 Chapter 6