Alignment - Vertex Standard VX-4000L Service Manual

The VX-4000 has been carefully aligned at the
factory for the specified performance across the fre-
quency range specified for each version.
Realignment should therefore not be necessary
except in the event of a component failure, or when
altering the transceiver version. If a sudden prob-
lem occurs during normal operation, it is likely due
to component failure; realignment should not be
done until after the faulty component has been re-
placed. All component replacement and service
should be performed only by an authorized
VERTEX STANDARD representative, or the warran-
ty policy may be voided. Therefore, if a fault is sus-
pected, contact the dealer from whom the transceiver
was purchased for instructions regarding repair.
Authorized VERTEX STANDARD service tech-
nicians realign all circuits and make complete per-
formance checks to ensure compliance with factory
specifications 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 must reserve the right
to change circuits and alignment procedures in the
interest of improved performance, without notify-
ing owners.
Under no circumstances should any alignment
be attempted unless the normal function and oper-
ation of the transceiver are clearly understood, the
cause of the malfunction has been clearly pinpoint-
ed and any faulty components replaced, and the
need for realignment determined to be absolutely
necessary.
Required Test Equipment
The following test equipment (and thorough fa-
miliarity with its correct use) is necessary for com-
plete realignment. Correction of problems caused
by misalignment resulting from use of improper test
equipment is not covered under the warranty poli-
cy.
While most steps do not require all of the equip-
ment listed, the interactions of some adjustments
may require that more complex adjustments be per-
formed afterwards. 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 beginning, and follow all of the steps in a sec-
tion in the order presented.
VX-4000 VHF Low-band Service Manual
r RF signal generator: calibrated output level at
1000 MHz
r Deviation Meter (linear detector)
r AF Millivoltmeter
r SINAD Meter
r Inline Wattmeter with 5% accuracy at 1000 MHz
r Regulated DC Power Supply: adjustable from 10
to 17 VDC, 15A
r 50-Ohm non-reactive Dummy Load: 100 W at
1000 MHz
r Frequency Counter: <0.1 ppm accuracy at 1000
MHz
r AF Signal Generator
r DC Voltmeter: high impedance
r RF Sampling Coupler(attenuation pad)
r AF Dummy Load: 4 Ohms, 20W
r Oscilloscope
r Spectrum Analyzer
r IBM PC-compatible computer w/VERTEX
STADARD CT-71 programming cable and CE35
channel programming editor.
Alignment Preparation & Precautions
A dummy load and inline wattmeter must be con-
nected to the main antenna jack in all procedures
that call for transmission, except where specified
otherwise. Correct alignment is not possible with
an antenna. After completing one step, read the fol-
lowing step to determine whether the same test
equipment will be required. If not, remove the test
equipment (except dummy load and wattmeter, if
connected) before proceeding.
Correct alignment requires that the ambient tem-
perature be the same as that of the transceiver and
test equipment, and that this temperature be held
constant between 68° and 86°F (20° ~ 30°C). When
the transceiver is brought into the shop from hot or
cold air it should be allowed some time for thermal
equalization with the environment before alignment.
If possible, alignments should be made with oscilla-
tor shields and circuit boards firmly affixed in place.
Also, the test equipment must be thoroughly
warmed up before beginning.

Alignment

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