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5-48
690XXB/691XXB MM
TROUBLESHOOTING
TROUBLESHOOTING
TABLES
Output Power Related Problems
(>40 GHz)
690XXB/691XXB Models with SQM
Error 136 SQM Unit or Driver Failed
Description: Error 136 indicates a failure of the SQM or a failure of
the SQM bias regulator or frequency band selection circuitry on the
A14 YIG, SDM, SQM Driver PCB. The 690XXB/691XXB will not pro-
duce an RF output above 40 GHz.
Step 1.
Set up the 690XXB/691XXB as follows:
a. 690XXB Setup:
CW/SWEEP SELECT: Step
F1: 40.0 GHz
F2: 50.0, 60.0, or 65.0 GHz (Model dependent)
Number of Steps: 400
L1: –2.0 dBm
691XXB Setup:
CW/SWEEP SELECT: Analog
F1: 40.0 GHz
F2: 50.0, 60.0, or 65.0 GHz (Model dependent)
Sweep Time: 0.100 Sec
L1: –2.0 dBm
Step 2.
Connect the X input of an oscilloscope to the 690XXB/
691XXB rear panel
HORIZ OUT
connector.
Step 3.
Using the oscilloscope, check the following voltages:
a. For models having a high end frequency of 50 GHz,
check the SQM bias voltages at A14TP8 and A14TP9.
The bias voltage at A14TP8 should be +10 volts; the bias
voltage at A14TP9 should be –5 volts.
For models having a high end frequency of 60 or 65 GHz,
check for a +11 volts SQM bias voltage at A14TP8.
b. For all models, check for a –2 volt PIN switch drive volt-
age at A9TP22.
q
If the SQM bias and the PIN switch drive voltages are
correct, go to step 4.
q
If the SQM bias voltage(s) is not correct, replace the
A14 PCB.
q
If the PIN switch drive voltage is not correct, replace
the A9 PCB.
Table 5-24.
Error Message 136 (1 of 2)
NOTE
When replacing the A14 PCB,
refer to Table 6-1, page 6-12, for
the correct part number and
switch S1 setting for the re-
placement PCB.
Summary of Contents for 680 C Series
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