Racal Instruments RA6790/GM, Техническое руководство

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Racal RA6790/GM Alignment & Tuning Manual
Page 2 of 20
CHAPTER 3
ASSEMBLED RECEIVER ALIGNMENT AND TEST
3-1. INTRODUCTION.
This chapter provides both alignment procedures and an end -to-end check for an
assembled Receiver. The information is presented in two sections with alignment
procedures contained in Section I and procedures for an end-to-end check
presented in Section II. The alignment procedures are designed to permit
alignment of any one or all of the various functions in the Receiver; however, the
adjustments in some functions interact with other functions so chat care must be
taken when any one function alone is aligned. The end-to-end checks are designed
to make sure that a Receiver is operational after assembly of new or repaired circuit
cards or modules.
SECTION I. ASSEMBLED RECEIVER ALIGNMENT
3-2.
GENERAL.
The circuit card and module assemblies may be aligned and checked after they are
installed in a working Receiver. The following paragraphs provide detailed step-by-
step instructions for aligning the Receiver assemblies. The alignment procedures
require that external power be connected to the Receiver, the Receiver power
switch turned on and that the mode, bandwidth,
AGC and frequency be set as
described in each procedure.
Refer to
T.O. 31R2 -2 U RR-251 for location of circuit cards and adjustments.
a. Power Supply Assembly AlO .
The power supply used in the Receiver does not contain any adjustments or
controls other than the line voltage select card located in A10J1. If all voltages
checked correctly as specified in Section XI of Chapter 2, it can be assumed that
the power supply is functioning properly. If the power supply has not been tested
then the 3-1 voltage levels as spelled out in Chapter 2 should be checked before
performing any alignment procedures.
WARNING
The filter capacitors used in the power supply will retain an electrical charge after
power is removed.
The capacitors should be discharged slowly by shorting the terminals through a
protected resistive device. Disconnect the
ac line cord from A10J1. Remove the
metal cover from the power supply and then reinsert line cord and turn Receiver
power on. Using the digital
multimeter, check the voltages appearing on connector