User`s guide

Chapter 3 3-17
Theory of Operation and Troubleshooting
Troubleshooting
Port 1 Test
Figure 3-7 Good Port 1 A Channel Response
With the analyzer connected as shown in Figure 3-2, press Preset, Start,
300, k/m, Meas, INPUT PORTS, A, TESTPORT 2
.
If there is a power hole or roll off in the response, check the RF cables.
Refer to Figure 3-14, Figure 3-15, or Figure 3-16 for cable locations.
If no response is seen for channel A, check the bias connection to switch
S3 (see Figure 3-13) and the J4 connections (see Figure 3-17) on the test
set interface board. If the bias connector is loose, reconnect it. If the bias
connector is firmly in place in the J4 connector, check the bias voltages
(+0.62 Vdc and +16.3 Vdc) on switch S3. The center bias pin on S3 should
be approximately +22 V.
1. Use the tab on the side of one of the switches (S0, S1, S2) as the
ground connection point.
2. The red wire is the common drive pin and should measure
approximately +22 Vdc.