TM 11-6625-2781-14&P-2
mode the-10 volt dc level is applied through CR 2 in the
SERVICE SHEET 11
bandwidth switch assembly and disable the bandwidth
selection circuits and insure that the 30 kHz bandwidth is
Normally malfunctions which occur in the switching circuits will
used.
be detected and corrected while troubleshooting crystal and
LC filter circuit in the IF section.
TEST PROCEDURE. See 2
TROUBLESHOOTING PROCEDURE
2
P/O BANDWIDTH SWITCH ASSEMBLY
Since these switches function for voltage switching only, all
This portion of the bandwidth switch assembly provides
components and wiring can be checked by monitoring voltage
positive or negative voltages to various IF section diodes and
levels at the input connector to the IF section 3 MHz IF
relays to add. bypass, or remove bandwidth shaping
AMplifier. LC Filter assembly, and the Crystal Filter assembly.
elements in the signal path.
EQUIPMENT REQUIRED
TEST PROCEDURE
Service Kit ............................................................. HP 11592A
Digital Voltmeter ............................................HP 3440/3443A
Use the HP 3440/34-13A Digital Voltmeter to verify switching
voltages at pins of XA1 and XA1 of the IF section for
CONTROL SETTINGS
operation of SCAN WIDTH switch, and BANDWIDTH
As required to check dc levels
switches. The voltages shown in the chart below are typical.
1
P/O SCAN WIDTH SWITCH
If all voltages are correct the portions of the SCAN WIDTH
and BANDWIDTH switches shown on Service Sheet 11 are
The switch section shown provides -10 volts to the bandwidth
functioning properly.
switch assembly for use in selecting desired bandwidths when
the analyzer is operated in the ZERO or PER DIVISION
If negative dc levels are missing check the SCAN WIDTH
modes. When the analyzer is operated ill the 0 to 100 .MHz
switch contacts, diodes, and the power supply. If positive dc
levels are missing check the bandwidth circuit and the power
supply.
Bandwidth Switch Settings (kHz)
Pin of XA1
0.1/0.5
0.3/0.5
.1
.3
1
3
10
30
100
300
6*
+1
+1
+1
+1
+.46
+.46
-9.4
-8.7
8.6
7.9
6**
-8.7
-8.7
-8.7
-8.7
-8.7
'-8.7
-8.7
-8.7
-8.7
8.7
8**
+5
+5
+5
+5
+5
+5
+5
+5
5
10
8**
-9.2
-92
-9.2
-9.2
-9.2
-9.2
-9.2
-9.2
9.2
9.2
10*
+20
+20
+20
+20
+20
+20
+20
+20
9.2
+20
10**
+20
+20
+20
+20
+20
+20
+20
+20
0
+20
12*
+20
+20
+20
+20
+20
+20
+20
-9.2
+20
+20
12**
+20
] +20
+20
+20
+20
+20
+20
0
+20
+20
Pin of XA4
7*
-8.4
-9.2
+20
+20
+20
+20
+20
+20
+20
+20
7**
+1.2
0
+20
+20
+20
+20
+20
+20
+20
t20
8*
+20
+20
-9.2
+20
+20
+20
+20
+20
+20
+20
8**
+20
+20
0
+20
+20
+20
+20
20O
+20
+20
10*
+20
+20
+20
-9.2
+20
+20
+20
+20
+20
+20
10**
+20
+20
+20
0
+20
+20
+20
+20
+20
+20
11*
+20
+20
+20
+20
-9.2
+20
+20
+20
+20
+20
11**
+20
+20
+20
+20
+20
+20
+20
+20
+20
+20
13*
+.47
+.47
+.47
+.47
+.47
+.47
-9.4
-8.7
-8.6
-7.6
13**
-'10
-10
-10
-10
-10
-10
-10
-10 .
-10
-10
*PER DIVISION
**0-100 MHz or ZERO
8-44
