Nautel Vector-LP VR125 Technical Instruction Manual

Contents

Vector-LP Radio Beacon Transmitter Technical Instruction Manual Page 4-1Section 4 Testing and Adjustment Issue 1.1Vector-LP Radio Beacon TransmitterTECHNICAL INSTRUCTION MANUALSection 4 TESTING AND ADJUSTMENT4.1 INTRODUCTIONThis section contains step-by-stepfunctional test procedures using integralmeters and precision test/monitoringequipment. The test procedures containroutine adjustment instructions to bring theparameter being tested within definedlimits, where appropriate.NOTENautel recommends all instructions befollowed in the order presented, particularlyby personnel who are not familiar withdetailed circuit theory and may not realizethe impact a specific adjustment can haveon other steps. These adjustments shouldbe performed during initial turn-on and aftermajor repairs or a frequency change.4.2 OPERATING PRECAUTIONSThe transmitter contains protection circuitsthat monitor critical parameters. When thedefined limits of any of these parametersare exceeded, one of the operational lampson the exciter panel’s system diagram willturn red. If the alarm condition could resultin excessive power amplifier stress current,the control voltage applied to the poweramplifiers will effectively be reduced orturned off until the out-of-tolerancecondition no longer exists. Maintainersshould read and fully understand theSection 3 - Operating Instructions, and inparticular the section on controls andindicators.NOTEThe diagnostic display’s meters screendisplays three pre-determined parameters(e.g., forward power, total dc current, +15 Vpower supply, etc.). All transmitterparameters may be displayed on thisscreen. See paragraph 3.6.8.1.4.3 FUNCTIONAL TESTSTo verify the transmitter circuits are withinfactory specifications, complete the tests inthis section. In cases where a routineadjustment will correct an out-of-tolerancecondition, the adjustment procedure isincluded.NOTEIf an in-tolerance condition cannot beattained with the specified routineadjustment, discontinue testing until thecause of the out-of-tolerance condition iscorrected.4.3.1 GeneralFunctional tests should be performed as aroutine part of scheduled maintenancechecks, and as the first step introubleshooting procedures. The resultsshould be recorded for comparison withpast and future test results.4.3.1.1 The functional test procedures areprovided in a step-by-step format. Thismethod of presentation will permit a personwho is unfamiliar with the transmitter toperform the functional tests in a logicalsequence. The procedures should becompleted in sequence, as each procedureestablishes switch settings and containsprerequisites for subsequent procedures.4.3.1.2 The following assumes the initialturn-on procedure detailed in Section 2 hasbeen completed during initial installation,and after major repairs that warrant theinitial start-up procedure be repeated.