Keysight N9038A, Service Manual

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284 Keysight N9038A MXE Service Guide
Front End Control
A15 Front End Control Assembly Troubleshooting
A11 RF Switch / High Band Preamp Control -
(Option 503, 508, & 526 only)
A problem with the A11 RF Switch / High Band Preamp assembly could be
caused by either a failure of the assembly itself, the control logic sent to it, or
damage to the cable between the two. This section will verify the functionality
of the control logic coming from the A15 Front End Control assembly. If after
verifying that the control logic in working properly refer to Chapter 6, “RF
Downconverter Section.” for further troubleshooting information on the A11
RF Switch / High Band Preamp assembly itself.
This section will verify the control signals from the A15 Front End Control
assembly to the A11 RF Switch / High Band Preamp assembly. As can be seen
in Figure 8-9 , in addition to the bias and control signals there are also two
controls for the A11 RF Switch / High Band Preamp assembly:
1. Supply Voltages
2. Serial Communication for Assembly Identification
3. Band Switch Control
4. High Band Preamp Switch Control
The status of these controls can be measured on the Front End Control Test
board assembly with the use of four test points, In1A, In2A, In1B, and In2B, as
can be seen in Figure 8-10 .
Figure 8-9 A11 RF Switch / High Band Preamp Diagram