AR 10036733, Operating And Service Manual

Page: 36 / 44

Model 30S1G6
4.3 TROUBLESHOOTING
CAUTION:
The microwave transistors used in the Model 30S1G6 amplifier are GaN
FETs. These devices are very reliable when installed in a suitable circuit,
but they can be easily damaged by improper troubleshooting or handling
techniques.
The gate junctions of the GaN FETs have a high input impedance and are
susceptible to static damage or damage due to the use of an ungrounded
soldering iron. Do not try to check the GaN FETs with an ohmmeter.
Use caution when troubleshooting the GaN FETs; do not short the gate to
the ground or to the drain.
CAUTION:
Use care when unpacking new GaN FETs. The GaN FET packaging
should only be opened at Electrostatic Discharge (ESD)-approved
workstations, by individuals who are familiar with the handling of
microwave GaN FETs and other ESD-sensitive devices.
Troubleshooting the Model 30S1G6 in a logical manner can speed the solution to a problem. The settings of
potentiometers (pots), capacitors (caps), or other variables should not be disturbed until other problems have
been eliminated. Comparing the measured DC voltages to those shown on the schematics can solve many
problems. Before measuring circuit voltages, first verify that the voltages to the circuits are correct.
Model 30S1G6 troubleshooting symptoms and remedies are described in the sections that follow

4.3.1—Power On Indication Doesn’t Display on Front Panel when POWER Switch is Depressed

4.3.2—The Unit Cannot be Operated Remotely

4.3.3—Thermal Fault

4.3.4—Interlock Fault

4.3.5—PS1 Fault

4.3.6—Amplifier Faults

4.3.7—Low or No Power Output (DC Tests)

4.3.8—Low or No Power Output (RF Test)
20 Rev A