Standard Horizon HX471S, Руководство по обслуживанию

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11
Alignment
The HX471S has been carefully aligned at the factory for
the specified performance across the marine, FRS, MURS,
AIR, AM broadcast and FM broadcast bands.
Realignment should therefore not be necessary except in
the event of a component failure. All component replace-
ment and service should be performed only by an autho-
rized Standard Horizon representative, or the warranty
policy may be voided.
The following procedures cover the sometimes critical and
tedious adjustments that are not normally required once
the transceiver has left the factory. However, if damage
occurs and some parts are replaced, realignment may be
required. If a sudden problem occurs during normal oper-
ation, it is likely due to component failure; realignment
should not be done until after the faulty component has
been replaced.
We recommend that servicing be performed only by au-
thorized Standard Horizon service technicians who are
experienced with the circuitry and fully equipped for re-
pair and alignment. Therefore, if a fault is suspected, con-
tact the dealer from whom the transceiver was purchased
for instructions regarding repair. Authorized Standard
Horizon service technicians realign all circuits and make
complete performance checks to ensure compliance with
factory specifications after replacing any faulty compo-
nents.
Those who do undertake any of the following alignments
are cautioned to proceed at their own risk. Problems caused
by unauthorized attempts at realignment are not covered
by the warranty policy. Also, Standard Horizon a division
of the VERTEX STANDARD must reserve the right to
change circuits and alignment procedures in the interest
of improved performance, without notifying owners. Un-
der no circumstances should any alignment be attempted
unless the normal function and operation of the transceiv-
er are clearly understood, the cause of the malfunction has
been clearly pinpointed and any faulty components re-
placed, and the need for realignment determined to be
absolutely necessary.
The following test equipment (and thorough familiarity
with its correct use) is necessary for complete realignment.
Correction of problems caused by misalignment resulting
from use of improper test equipment is not covered under
the warranty policy. While most steps do not require all of
the equipment listed, the interactions of some adjustments
may require that more complex adjustments be performed
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 fol-
low all of the steps in a section in the order presented.
Required Test Equipment
RF Signal Generator with calibrated output level at 500
MHz
Deviation Meter (linear detector)
AF Millivoltmeter
SINAD Meter
Inline Wattmeter with 5% accuracy at 500 MHz
Regulated DC Power Supply: adjustable from 6 to 17
VDC, 3A
50-ohm Non-reactive Dummy Load: 10W at 500 MHz
Frequency Counter: >0.1 ppm accuracy at 500 MHz
AF Signal Generator
DC Voltmeter: high impedance
VHF Sampling Coupler
AF Dummy Load: 8 ohm, 2W
Oscilloscope
Spectrum Analyzer
Special Screw Driver (VXSTD P/N: S7000421)
Alignment Preparation & Precautions
A dummy load and inline wattmeter must be connected
to the main antenna jack in all procedures that call for trans-
mission, except where specified otherwise. Correct align-
ment is not possible with an antenna. After completing one
step, read the following step to determine whether the same
test equipment will be required. If not, remove the test
equipment (except dummy load and wattmeter, if connect-
ed) before proceeding.
Correct alignment requires that the ambient temperature
be the same as that of the transceiver and test equipment,
and that this temperature be held constant between 20 and
30 °C (68 and 86 °F). 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 be-
fore alignment. If possible, alignments should be made with
oscillator shields and circuit boards firmly affixed in place.
Also, the test equipment must be thoroughly warmed up
before beginning.
Note : Signal levels in dB referred to in this procedure are
based on 0 dBm = 0.5 µV(closed circuit).
Marine Division of Vertex Standard
10900 Walker Street, Cypress, CA 90630, U.S.A
Telephone number: (714) 827-7600