14-18
Block Diagram Theory of Operation

Block Diagram 5

Block Diagram 5
This block diagram illustrates the busses that interconnect the instrument controllers (A7
Controller, A32 GSM Controller, A34 GSM RTI, and A37 Sequence Controller) with the
other assemblies. Chapter 5 “Troubleshooting the Controller/Display” contains
informationabout troubleshooting and an explanation of the serial and parallel busses that
interconnect the assemblies.
A19 Measurement
The A19 Measurement assembly contains the circuits necessary to measure voltage and
countfrequency. These circuits are interconnected throughout the instrument with a series
of multiplexers. The measurement board also synchronizes the measurements for the
spectrumanalyzer and the oscilloscope display. The block diagram shows the pin numbers
and signal names of most voltage and counter inputs to this assembly.
While there are no specific diagnostics for the A19 Measurement assembly, it is used
extensively to diagnose other parts of the instrument. If the diagnostics incorrectly
indicate a faulty assembly, the measurement board may be a likely cause. Use the pin
number information to verify that the voltages and frequencies are properly transferred
from the modules to the A19 Measurement assembly.
A33 Hop Controller
TheA33 Hop Controller assembly controls the I/O to most analog and RF hardware in the
instrument. Problems with this assembly will usually appear as multiple failures during
the power up diagnostics (as indicated on the A7 LED’s). The A33 Hop Controller
assembly communicates to the main controller (A7 Controller) with a parallel bus, and
through a serial bus to the other analog hardware. This illustration is included with pin
numbers to allow troubleshooting the serial busses and communication failures to the
modules. Again, no specific memory card diagnostics exist for this module. It is unlikely
that memory card programs could be executed if the A33 Hop Controller assembly is
defective.
To understand more about the serial and parallel busses connected to the A33 Hop
Controller assembly, refer to the chapter 5 discussion.