AR 10037990, Operating And Service Manual, Page: 31 / 54

Model 250T6G18
Rev A 11
6. Gasket must be seated completely in waveguide groove. NOTE: If the gasket is not seated fully, it will pinch
between the two parts and impair the connection. See below:
Not seated fully
CORRECT INCORRECT
7. Align waveguide with receptacle. Loosely install all hardware. If the waveguide does not align properly, do
not proceed.
8. Tighten hardware in a crisscross pattern to assure even torque distribution. Double check that all hardware has
been tightened fully to ensure no leakage.
9. The open ends of all waveguide must be covered with either Kapton tape or plastic waveguide covers.
3.2.7 External Interlock Connector
The TWTA is provided with external interlock capability via a 15-pin female D-sub connector, J3. To enable the
high voltage power supply, it is necessary to provide continuity between J3 pins 3 and 4. If the amplifier shuts
down because the interlock was opened, it will be necessary to reset the system to return to standby (see
System
shutdown screen in Section 3.4). In addition, there is an external inhibit capability via the same connector, J3. To
enable RF ON (beam on), continuity must be provided between J3 pins 10 and 11. If continuity is broken, the
TWT beam will shut off until continuity is restored. No reset is required to return to RF ON. Users may adopt the
interlock and inhibit features to disable the HPA for either equipment protection or as a backup for personnel
protection.
CAUTION:
Do not rely on the external interlock for personnel protection. The intent
of the external interlock feature is to disable the RF output for equipment
protection. Use proper operating and safety procedures to insure that
power is removed for personnel safety.
The amplifier has an internal jumper between J3 pins 1 and 2 that may be used by the customer to verify
installation of the HPA in the overall system by means of a continuity string.