AR 10006031, Operating And Service Manual

Page: 38 / 62

Model 200T4G8
If significant dust has been noted on the air intake grill, it may be desirable to vacuum the dust and debris
from inside the enclosure. To open the enclosure:
1. Remove the amplifier from the cabinet or rack as follows:
NOTE: Due to the weight of the unit, the removal of the amplifier from the cabinet or rack is a two-
person operation.
Disconnect power, RF and any other interface connectors. On the rear of the unit, remove any screws
used to connect brackets to amplifier (two on each bracket). On the front of the unit, remove the four
screws (two outside screws on each side) mounting the front panel to the cabinet. Carefully slide the
amplifier out of the front of the cabinet.
2. Remove the six screws that secure the lower cover and the six screws that secure the upper cover.
Remove the covers to gain access to the interior of the TWTA.
Vacuum dust and debris from inside the enclosure. Clean dust from the TWTA and its flying leads. Remove
any dirt from around the five high voltage connectors. While the cover is off, check for loose wires,
components or fasteners
Reassemble in reverse order.
4.4 TROUBLESHOOTING
Symptom Possible Cause
TWT or power supply overtemperature Air inlet filter dirty
Collector heat sink dirty
Inadequate clearance behind TWTA
High air inlet temperature
Defective blower or power supply
No response when main power turned on Panel open interlock switch open
Control module display does not come up; unit does not beep when
powered up Shorted or defective control module power supply
Control module failure
Control module does not boot EPROM(s) missing.
Control module datalink failure error appears
HPA interface failure.
Fiberoptic link failure
+15 VDC supply failure
Heater power supply does not come up
Defective low voltage power supply module
Defective heater power supply module
No high voltage
Open external interlock
Keylock switch on
INHIBIT or REMOTE
Defective high voltage power supply.
Voltages normal, but no RF output, helix current low
No RF input
Defective remote control board
Defective SSA
Gain turned down
Open inhibit
28 Rev. F