AR 100A400AM20, Operating And Service Manual

Page: 43 / 46

Model 100A400AM20
Rev A 27
4.3.5 PS2 Fault (Schematic 10047796)
The PS2 power supply has DC OK output which is normally low (< 0.1V) to the A4 J13, pin 30. If any of
the PS2 outputs fail, this output will go high (> 4.0V) and inhibit the A1 High Gain Amplifier.
4.3.6 Amplifier Faults (Schematics 10047796 and 10039874)
1. The fault output of the A2 power module is sensed on A4, J13, pin 10.
2. The Amplifier Fault LED (DS2) should be lit, indicating a module failure.
3. Verify the correct voltages to the modules. Troubleshoot any incorrect voltages.
FL1 = +40.0 ± 0.3V
FL5 = –15.0 ± 0.3V
4.3.7 Low or No Power Output (DC Tests) (Schematic 10047796)
All indicators are normal, the front panel display reads Power On , and the cooling fans B1, B2 are operating.
1. Check the position of the RF Gain control—is it set to maximum gain?
2. Check the RF input to the unit—is it the correct amplitude and frequency?
3. Check the RF output connection from the unit—is it correctly connected to the load?
Is the coaxial cable okay?
4. Check the following voltages on the Power Supply. If any of the voltages are out of tolerance, correct
them before further troubleshooting.
PS1 J18 Pin 5
+15 V
±
0.5 V
PS1 J18 Pin 8 -15 V ± 0.5 V
5. Check the voltage on the feed thru caps of the A1 Pre-Amp, with the RF gain control at maximum gain.
Troubleshoot any incorrect voltages.
FL2
+24 V
±
0.5 V
FL3 -15 V ± 0.5 V
FL4 +4.7 V
±
0.5 V
6. Check the voltages on the feed-thru caps of A2.
FL1
+40.0 V
±
0.3 V
FL4 +15 V ± 0.3 V
FL5 –15.0 V
±
0.3 V