Yaesu VX-450 series Service Manual Download Page 30

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VX-450 Series UHF Band Service Manual

Alignment

Introduction

The

VX-450

series is carefully aligned at the factory

for the specified performance across the frequency
range specified for each version. Realignment should
therefore not be necessary except in the event of a
component failure, or altering version type. All com-
ponent replacement and service should be per-
formed only by an authorized

Vertex Standard

rep-

resentative, or the warranty policy may be void.

The following procedures cover the sometimes crit-
ical and tedious adjustments that are not normally
required once the transceiver has left the factory.
However, if damage occurs and some parts subse-
quently are replaced, realignment may be required.
If a sudden problem occurs during normal opera-
tion, it is likely due to component failure; realign-
ment should not be done until after the faulty com-
ponent has been replaced.

We recommend that servicing be performed only by
authorized

Vertex Standard

service technicians who

are experienced with the circuitry and fully equipped
for repair and alignment. Therefore, if a fault is sus-
pected, contact the dealer from whom the transceiv-
er was purchased for instructions regarding repair.
Authorized

Vertex Standard

service technicians re-

align all circuits and make complete performance
checks to ensure compliance with factory specifica-
tions after replacing any faulty components.

Those who do undertake any of the following align-
ments are cautioned to proceed at their own risk.
Problems caused by unauthorized attempts at re-
alignment are not covered by the warranty policy.
Also,

Vertex Standard

reserves the right to change

circuits and alignment procedures in the interest of
improved performance, without notifying owners.

Under no circumstances should any alignment be
attempted unless the normal function and operation
of the transceiver are clearly understood, the cause
of the malfunction has been clearly pinpointed and
any faulty components replaced, and realignment
determined to be absolutely necessary.

The following test equipment (and thorough famil-
iarity with its correct use) is necessary for complete
realignment. Correction of problems caused by mis-
alignment resulting from use of improper test equip-
ment is not covered under the warranty policy. While
most steps do not require all of the equipment list-
ed, the interactions of some adjustments may require
that more complex adjustments be performed after-
wards. Do not attempt to perform only a single step
unless it is clearly isolated electrically from all other
steps. Have all test equipment ready before begin-
ning, and follow all of the steps in a section in the
order presented.

Required Test Equipment



RF Signal Generator with calibrated output level
at 600 MHz



Oscilloscope



Deviation Meter (linear detector)



In-line Wattmeter with 5 % accuracy at 600 MHz



50 Ohm RF Dummy Load with power rating 10
W at 600 MHz

