AR 10052412, Operating And Service Manual

Page: 72 / 80

Model 5000A225C
48 Rev A
4.3.8 Low or No Power Output (DC Tests) (Schematic 10052498 LV,
10052499 HV)
All indicators on the Model 5000A225C are normal, the front panel display reads RF On, and the cooling fans
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 Pins 1 and 2
+5V ± 0.3 V
Pin 5 +15.0V
±
0.3 V
Pin 8
-15.0V ± 0.3 V
PS2 +V
+28V ± 0.3 V
PS3 +V +34V
±
0.3 V
PS4 through PS12 +V
+48 V ± 0.3 V
5. Check the voltage on the feed thru caps of the A1 pre-amplifier, with the RF gain control at maximum gain.
Troubleshoot any incorrect voltages.
FL1 = +4.2V ± 0.3V
FL2 = +28V ± 0.3V
FL3 = -15V ± 0.3V
6. Check the voltages on the feed-thru caps of Driver Module A2.
FL1 = +34 ± 0.3V
FL5= –15 ± 0.3V
FL4 = +15 ± 0.3V
7. Check the voltages on the feed-thru caps of Final Modules A14 through A29 and A30 through A45.
C2A, C2B = +48 ± 0.3V
C3= –15 ± 0.3V
C4 = +15 ± 0.3V