Preventative Maintenance Guide For Mt3300 Mt3400 Twta
Preventative Maintenance Guide For Mt3300 Mt3400 Twta
Preventative Maintenance Guide For Mt3300 Mt3400 Twta
Technical Note
August 1, 2002
TABLE OF CONTENTS
WARNING AND CAUTION statements have been strategically placed in the text to emphasize
certain steps or procedures for the protection of personnel (WARNING) or equipment
(CAUTION). A WARNING or CAUTION once provided will apply each time the related step
is repeated, regardless of the number of times the WARNING or CAUTION is repeated
throughout the text. Prior to starting any task, THE WARNINGS or CAUTIONS included in
the text for that task should be reviewed and understood.
WARNING
CAUTION
NOTE
The following are general safety precautions and instructions that personnel must understand
and apply during many phases of operation and maintenance to ensure personnel safety and
health and the protection of property. Portions of this information may be repeated in certain
chapters of this publication for emphasis.
WARNING AND CAUTION statements have been strategically placed in the text to emphasize
certain steps or procedures for the protection of personnel (WARNING) or equipment
(CAUTION). A WARNING or CAUTION once provided should apply each time the related
step is repeated, regardless of the number of times the WARNING or CAUTION is repeated
throughout the text. Prior to starting any task, The WARNINGS or CAUTIONS included in
the text for that task should be reviewed and understood.
Operating personnel must at all times observe safety regulations. Do not replace components or
make adjustments inside the equipment with the voltage supply turned on. Under certain
conditions, dangerous potentials may exist when the power control is in the off position, due to
charges retained by capacitors. To avoid injuries, always remove power from, discharge, and
ground a circuit before touching it. Adhere to all lock out/tag out requirements.
Do not attempt internal service or adjustment unless another person capable of rendering aid and
resuscitation is present.
RESUSCITATION
Personnel working with or near dangerous voltage shall be trained in modern methods of
resuscitation.
COMPRESSED AIR
Use of compressed air for cleaning can create an environment of propelled foreign particles. Air
pressure shall be reduced to less than 30 psi and used with effective chip guarding and personnel
protective equipment.
The operation of this amplifier may involve some of the following hazards; any of them could
result in serious harm to personnel if proper safety precautions are not taken.
WARNING
HIGH VOLTAGE
WARNING
RF RADIATION
WARNING
BERYLLIUM OXIDE
WARNING
IMPLOSION HAZARD
WARNING
X-RAY RADIATION
WARNING
HOT SURFACES
Surface temperature of tubes and other air cooled parts can reach
several hundred degrees centigrade.
CAUTION
RF OVERDRIVE
Drive levels as low as –17 dBm may damage the unit for the Model
MT3300/MT3400 depending upon the settings of the system attenuator.
Please apply RF with caution. Always terminate RF input and output
ports properly when AC power is supplied to the TWTA.
2.0 SCOPE
This document contains a preventative maintenance schedule for normal operating conditions
and instructions for simple maintenance tasks, which should be performed regularly. This
document also explains why it is important to keep your amplifier system well maintained and
follow basic safety precautions. This document assumes a familiarity and working experience
with high power microwave RF amplifiers.
The following table is showing the maintenance schedule for the MT3300/MT3400. There are
three maintenance intervals broken down into separate tables. The MT3300/MT3400 should be
inspected to permit early detection of wear or damage, which if properly corrected will prevent
equipment malfunction or failure. Examinations for wear, breaks, deterioration, excessive
moisture, mounting integrity and other defects should be made. If the equipment has been
subjected to severe environmental conditions, such as dust input ambient air, temperature
extremes, or excessive shock or vibration, inspections should be more frequently performed.
ITEM PROCEDURE
Verify air is flowing freely through the
HPA Heatsink. The HPA uses a
variable speed fan, when the tube
temperature drops below 50 degrees C
the fan will begin to cut back. Take this
into consideration when inspecting
airflow. Tube temp minus ambient may
HPA Cooling
be used as a service indicator. If this
delta increases cleaning may be
required. This can be accomplished by
using compressed air to clean fans
heatsink fins. If water is used HPA
must be off and cooled to minimize
thermal shock.
See the Downloading Status &
Downloading Settings paragraph of
Download HPA Configuration
TN3300/TN3400-3 Technical Note
Operation of MT3300/MT3400 TWTA.
ITEM PROCEDURE
Inspect the blower and the air channel
for any potential obstruction. Use
Blower compressed air or a vacuum to clean
the blower and the TWT heat sink
assembly.
WARNING
Although care has been taken in the design of the system to provide such features as an interlock
switch, high voltage points which are clearly marked, and warning labels affixed to the system, it
will be necessary to defeat the interlock switch when performing certain tests outlined in Table
4
There are two hardware configurations under the HPA cover. Refer to the diskette that was
provided with your amplifier (each diskette is unique to each amplifier). Compare the settings
on the diskette with the current values on the amplifier display; if there is significant difference,
then a re-calibration may be necessary. If you are equipped and able to perform High Voltage
measurements, then follow Table 4, if not contact MCL Customer Service for assistance.
FILAMENT FILAMENT
CATHODE CATHODE
HELIX HELIX
APPENDIX A – 46A0009