Model 350S1G6A
Rev C
35
4.3.6
Amplifier Faults (Schematics 10047656 and 10039045)
1.
The fault outputs for the 31 Quadrature-Coupled Amplifiers (Quad Amps) (A2, A8, A10-A13, A15, A24-
A27, A32-A47, A52-A55) are sensed on the A60 Control/Fault Board, J5, Pins 9 through 13 and on the
A64 and A69 Switch Breakout Boards, Pins 9 through 27.
2.
The amplifier’s top cover can be removed to allow access to Quad Amp A2. The side covers can be
removed to allow access to A8, A10-A13, A15, A24-A27, A32-A47, A52-A55 modules.
3.
The Amplifier Fault pin voltage should be logic low, indicating which Quad Amp(s) has failed.
4.
Verify the correct voltages to the Quad Amps. Troubleshoot any incorrect voltages.
C2 = +25.7 ± 0.5V
C1 = -5 ± 0.3V
C3=logic high (no fault)
4.3.7
ALC Fault
Indication –
ALC
As stated previously, the power limit controls could not limit either the forward or reverse power to the preset
threshold. This can be a transient type of problem, if the fault can be cleared. If the fault cannot be cleared
with no RF input drive power, then there is a malfunction in the ALC board or associated circuit.
4.3.8
Low or No Power Output (DC Tests) (Schematic 10047656)
All indicators on the Model 350S1G6A 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 Pin 5
+15.0 V
±
0.5 V
PS1 Pin 8
-15 V
±
0.5 V
PS2
+25.7 V
±
0.5 V
PS3
+25.7 V
±
0.5 V
5.
Check the voltage on the feed thru caps of the A2 Driver Amp. Troubleshoot any incorrect voltage.
C2
+25.7 V
±
0.5 V
C1
-5 V
±
0.3 V
6.
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.
C4
+15 V
±
0.5 V
C3
-5 V
±
0.3 V
C1
+5 V
±
0.3 V
C2
-12 V
±
0.5 V
