Source Group Troubleshooting Appendix - Agilent Technologies 8753ET Service Manual

Source Troubleshooting

Source Group Troubleshooting Appendix

Source Group Troubleshooting Appendix
Troubleshooting Source Problems with the Analog Bus
The analog bus can perform a variety of fast checks. However, it too is subject to failure
and thus should be tested prior to use. You should have done this in
To use the analog bus to check any one of the nodes, press
SERVICE MENU ANALOG BUS IN
enter the analog bus node number followed by
for additional information.
Phase Lock Diagnostic Tools
• error messages
• diagnostic routines
Phase Lock Error Messages
All phase lock error messages can result from improper front panel connections.
NO IF FOUND: CHECK R INPUT LEVEL means no IF was detected during pretune: a source
problem. Perform the
NO PHASE LOCK: CHECK R INPUT LEVEL means the IF was not acquired after pretune: a
source problem. Perform the
PHASE LOCK CAL FAILED means that a calculation of pretune values was not successful: a
source or receiver failure. Perform
page 3-10. If the analyzer fails that routine, perform the
page 7-8.
PHASE LOCK LOST means that phase lock was lost or interrupted before the band sweep
ended: a source problem. Refer to
phase lock loop diagnostic service routine. Then troubleshoot the problem by following the
procedures in this chapter.
Phase Lock Diagnostic Routines
Perform the following steps to determine at what frequencies and bands the phase lock
problem occurs.
1. Press
Preset System
switch off the automatic phase-locked loop. Normally, when the phase-locked loop
detects lock problems, it automatically aborts the sweep and attempts to recalibrate the
pretune cycle. Switching off PLL AUTO defeats this routine.
2. Press
PLL DIAG ON
this mode, the phase lock cycle and subsweep number are displayed on the analyzer
display. (See "Service Modes Menu" on page 10-16
7-30
. Then press
"A4 Sampler/Mixer Check" on page
"A4 Sampler/Mixer Check" on page
"Source Pretune Correction Constants (Test 48)" on
"Phase Lock Diagnostic Routines,"
SERVICE MENU
to switch on the phase-locked loop diagnostic service mode. In
Chapter 4
Preset
ANALOG IN Aux Input
Meas
. Refer to "Analog Bus" on page 10-20
x1
7-8.
7-8.
"A4 Sampler/Mixer Check" on
SERVICE MODES
for more information.)
.
System
and
next, to access the
to
PLL AUTO OFF
Chapter 7