AR 10046494, Operating And Service Manual, Page: 50 / 60

Model 60/40S1G18B
30 Rev A
4.3.11 High Band Amplifier Faults (DC Test) (Schematic 10046186)
1. The individual fault outputs for the A1A2 driver amplifier and the A4 and A5 20-watt module are sensed
on the A14A3 Switch Breakout Assy J5/P12, pins 9 & 10 respectively.
2. Verify the correct voltages to the RF stages. Troubleshoot any incorrect voltages.
A1A1 Preamplifier A1A2 Driver A4, A5 20-watt module
P1, pin 2 +12V P2, pin 1, 2 -5V P3, P4 pin 1, 2, 3 +26.3V
P1, pin 3 -12V P2, pin 4 +26.3V P3, P4 pin 6, 7 -5V
P1, pin 4, 5 -5V
P1, pin 6 +10V
4.3.12 Low Band Low or No Power Output (DC Tests) (Schematic
10046186)
All indicators on the Model 60/40S1G18B are normal, the front panel vacuum fluorescent display (VFD)
reads
Power On
, and the cooling fans (B6 and B7) 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.
PS3 C Module
+25.7 V  0.2 V
PS3 DB Module Channel 1 +24.0 V

0.5 V
PS3 DB Module Channel 2 N/A
5. Check the voltage on the feed thru caps of the A8 Driver Amp. Troubleshoot any incorrect voltage.
C4
+25.7 V  0.2 V
C1 -5 V  0.5 V
6. Check the voltage on the feed thru caps of the A7 Pre-Amp, with the RF gain control at maximum gain.
Troubleshoot any incorrect voltages.
A7, pin 3
-12 V

0.3 V
A7, pin 4,5 -5 V

0.3 V
A7, pin 6 +15 V  0.3 V
7. Check the voltages on the A10, A11, A12 and A13 Quad Amp; the voltage should be +25.7 ±0.3V.
A9/A10, pin 4
+25.7 V

0.2 V
A9/A10, pin 1 –5.0 V

0.3 V