5-4 MALFUNCTIONS NOT
DISPLAYING AN ERROR
MESSAGE
The 682XXB/683XXB must be operating to run self-test. Therefore,
malfunctions that cause the instrument to be non-operational do not
produce error messages. These problems generally are a failure of the
682XXB/683XXB to power up properly.Table 5-4, beginning on page
5-12, provides troubleshooting procedures for these malfunctions.
Malfunctions related to pulse modulating the RF output do not pro-
duce error messages. In those 682XXB/683XXB models that produce
RF outputs of >40 GHz, malfunctions related to quadrupling the
source signal do not generate error messages. Troubleshootingproce-
dures for these malfunctions are included in Table5-4.
5-5 TROUBLESHOOTING
TABLES Tables5-4 through 5-27, beginning on page 5-12, provide procedures
for isolating malfunctions to a replaceable subassembly or RF compo-
nent. In those cases where any of several subassemblies or RF compo-
nents could have caused the problem, subassembly/RF component re-
placement is indicated. The recommended replacement order is to
replace first the subassemblies/RF components that are most likely to
have failed.
Figure 5-1, on the following page, shows the location of the 682XXB/
683XXB connectors and test points that are called out in the trouble-
shooting procedures of Tables5-4 through 5-27.
CAUTION
Never remove or replace a subassembly or RF component
with power applied. Serious damage to the instrument may
occur.

5-10 682XXB/683XXB MM

MALFUNCTIONS NOT DISPLAYING

TROUBLESHOOTING AN ERROR MESSAGE