Troubleshooting R&S SMB
1407.0806.82 3.26 E-6
Perform the following settings at the R&S SMB:
• Preset
• RF on
• Unlock Protection Level 2: 147946
•
SETUP - Test Point Select Test Point DIAG_SMB_RF_LCON
• SETUP - Test Point State on
Preset the R&S SMB and control the following signals with an Oscilloscope.
Oscilloscope settings:
• Voltage: 1V / Div
• Timespan: 1 µs/ Div
• Trigger: Normal
Measure these signals
Test point Function Signal at normal operation Defective
P23, P25, P27, P28 Logic Control Signals Basis Board
P26 Logic Control Signal
Check the serial number of the RF
Board displayed in the GUI:
SETUP - Hardware-Config – RF
Board - More… If the number is
correct these signals are OK.
If not measure these Test-Points with
an Oscilloscope: They should toggle
between 0 V and 3.3 V
RF Board
P29, P31 Reset 3.3 V Basis Board
P30 Interrupt Signal normal Operation: 3.3 V
Switch R&S to Reference extern
without applying 10 MHz Reference
signal: 0 V
RF Board
P32 Blank Signal normal Operation: 0 V
during Frequency switching: + 3,3 V
Basis Board
P38 Diagnosis Voltage Voltage toggles on every update of the
diagnosis between 0 V and about 1/5
of the Diagnosis voltage reading in the
Display
RF Board
P20, P21, P22 Logic Control Signals Basis Board
P24 Logic Control Signal
Check the serial number of the
MOD-FPGA displayed in the GUI:
SETUP - Hardware-Config –
MOD-FPGA - More If the number is
not 0.0 these signals are OK.
If not measure these Test-Points with
an Oscilloscope: They toggle between
0 V and 3.3 V during the first seconds
after switching on the instrument
RF Board
If one of these Signals is not as described change the connector cable and test again. If the signals still
not match their description change the defective board according to the table.
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