Anritsu 37 D Series, Руководство по обслуживанию, Страница: 114 / 190

RF Unleveled
This problem is usually caused by setting the Source power above the
instrument capabilities for the frequency range selected. If the Source
power is set above default value (0 dB) and reducing the source power
causes the message to disappear, the 37XXXD is not malfunctioning.
If the message appears and the Source power is at default power or
lower, the 37XXXD is not operating correctly. Performing the Source
ALC Calibrations (Chapter 6) may solve the problem. If the problem
persists, the difficult nature of this problem means the best solution is
to return the VNA to an Anritsu Service Center for repair.
IF Cal Failures (during self-test or measurement)
If only “Test A” is noted on the front panel error message(s) or <OVL>
is present in the Service Log only in the “A” voltages section, the prob-
lem is most likely a fault of the A3 PCB.
If only “Test B” is noted on the front panel error message(s) or <OVL>
is present in the Service Log only in the “B” voltages section, the prob-
lem is most likely a fault of the A6 PCB.
If only “Ref ” is noted on the front panel error message(s) or <OVL> is
present in the Service Log only in the “R” voltages section, the problem
is most likely a fault of the A4 PCB.
If there are multiple (usually 3) “IF Cal Failure” error messages on the
37XXXD front panel or <OVL> appears in the “A,” “B,” and “R” volt-
ages sections of the Service Log, the problem is most likely a failure of
the 10 MHz internal time base. Replace the A7 PCB.
ERROR MESSAGES DURING MEASUREMENTS TROUBLESHOOTING
7-10 37XXXD MM