AR 10009284, Operating And Service Manual

Page: 39 / 62

Rev A 25
4. MAINTENANCE
The Model 40T26G40A TWTA does not require routine scheduled maintenance . The unit’s only moving
parts are the switches, the relays, and the blower. Preventive maintenance is recommended in section 4.3.
It is recommended that, whenever possible, the TWTA should be returned to the factory for repair . However ,
since limited logic schematics and partial parts information are supplied in this manual (see Section 5), some
user service organizations may choose to perform their own corrective maintenance
. Warnings and
Cautions should be observed.
4.1 SAFETY WARNING
WARNING:
Service work must be performed only by technicians thoroughly familiar
with the high voltages present in microwave tube amplifiers in general,
and with this equipment in particular.
Never handle the TWT leads or the high-voltage connectors unless the
unit is unplugged and it has been positively established that the high-
voltage filter capacitors have been discharged to a
known safe level.
CAUTION:
A malfunctioning power supply can cause damage to the TWT. If you are
troubleshooting the TWTA, remove the TWT and substitute suitable
loads to prevent damage to the TWT.
4.2 UNAUTHORIZED REPAIRS
CAUTION:
Unauthorized repairs or modification of this product during the warranty
period may void the warranty. In the event that the TWTA malfunctions
while it is still under warranty, always contact an authorized service
representative.
4.3 PREVENTIVE MAINTENANCE
The RF characteristics and power supply voltages and currents of the TWTA should be logged on a regular
basis. Maintenance should be performed if significant deviations from the logged values appear. If the unit is
under warranty, contact an authorized service representative if impaired performance is suspected.
If there is accumulated dust on the air intake grill, clean it with dry compressed air. 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.