CHPA SERIES
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6-1
6-1
Chapter 6
Maintenance
6.1 Overview
This chapter provides instructions for routine maintenance of the compact high power
Traveling Wave Tube Amplifier (CHPA) and performance testing. It covers procedures and test
equipment for scheduled maintenance tasks, electrical calibration, and performance testing. It
also explains how to diagnose and repair common problems to the circuit-card assembly level
(PCB).
Note: Improper maintenance of the CHPA may void the warranty. For
details, see Appendix D, “Warranty and Support Information.”
WARNING! THE PERSON PERFORMING MAINTENANCE OF THIS EQUIPMENT
MUST HAVE TRAINING AND KNOWLEDGE OF BOTH THE PRODUCT AND SAFETY
REQUIREMENTS AND SAFETY ISSUES RELATED TO THE EQUIPEMENT. READ
AND PRACTICE THE SAFETY GUIDELINES IN CHAPTER S AT THE FRONT OF
THIS MANUAL.
WARNING! IN SOME CASES IT MAY BE REQUIRED TO WORK ON THE
EQUIPMENT WITH EXPOSED LIVE VOLTAGES EXCEEDING 50 V. ACCESS INTO
THE CHPA AND WORKING CIRCUITRY WITH LIVE VOLTAGES EXCEEDING 50 V IS
RESTRICTED TO AUTHORIZED PERSONNEL SKILLED IN RF AMPLIFIERS AND
HIGH-VOLTAGE EQUIPMENT. THE PERSON EXPOSED TO LIVE VOLTAGES MUST
BE OBSERVED BY AT LEAST ONE OTHER PERSON ABLE TO SWITCH OFF THE
VOLTAGE WITHOUT DELAY. ALSO, THE OBSERVER SHOULD BE TRAINED TO
RENDER FIRST AID BY MEANS OF CARDIOPULMONARY RESUSCITATION (CPR).
THE OBSERVER MUST HAVE IMMEDIATE ACCESS TO THE MAIN CIRCUIT
BREAKER “EMERGENCY OFF” BUTTON. WORK SAFELY!
6.2 Scheduled Preventive Maintenance
To function safely and effectively, the CHPA requires periodic maintenance. This consists of
inspecting, cleaning, testing, and calibrating the HPA’s subsystems at one- to six-month
intervals. In addition, a daily log should be kept of all the CHPA meter readings, including
heater and beam hours of operation and any other trends. This can be helpful in identifying
emerging or continuing problems.