Vertex Standard FT-817, Руководство пользователя

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13
Alignment
Introduction
The FT-817 has been carefully aligned at the factory for
the specified performance across the amateur band. Re-
alignment should therefore not be necessary except in the
event of a component failure. All component replacement
and service should be performed only by an authorized
VERTEX STANDARD 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 op-
eration, 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 autho-
rized VERTEX STANDARD service technicians who are ex-
perienced with the circuitry and fully equipped for repair
and alignment. Therefore, if a fault is suspected, contact the
dealer from whom the transceiver was purchased for in-
structions regarding repair. Authorized VERTEX STAN-
DARD service technicians realign all circuits and make com-
plete performance checks to ensure compliance with fac-
tory specifications after replacing any faulty components.
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, VERTEX STANDARD must
reserve the right to change circuits and alignment proce-
dures in the interest of improved performance, without
notifying owners. Under no circumstances should any align-
ment be attempted unless the normal function and opera-
tion of the transceiver are clearly understood, the cause of
the malfunction has been clearly pinpointed and any faulty
components replaced, and the need for realignment deter-
mined to be absolutely necessary.
Required Test Equipment
The following test equipment (and thorough familiarity
with its correct use) is necessary for complete realignment.
Correction of problems caused by misalignment result-
ing from use of improper test equipment is not covered
under the warranty policy. While most steps do not re-
quire 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 be-
ginning, and follow all of the steps in a section in the or-
der presented.
r
RF Signal Generator with calibrated output level at 500
MHz
r
Deviation Meter (linear detector)
r
AC Voltmeter
r
SINAD Meter
r
Inline Wattmeter with 5% accuracy at 500 MHz
r
Regulated DC Power Supply: adjustable from 8 to 16.5
VDC, 5A
r
50-Ohm Non-reactive Dummy Load: 5 W at 500 MHz
r
150-Ohm Dummy Load: 5 W at 500 MHz
r
FM Linear Detector
r
Frequency Counter: ±0.1 ppm accuracy at 500 MHz
r
AF Signal Generator
r
DC Voltmeter: high impedance
r
VHF Sampling Coupler
r
AF Dummy Load: 4 Ohms, 5 W
Alignment Preparation & Precautions
A dummy load and inline wattmeter must be connected
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 complet-
ing 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
connected) before proceeding.
Correct alignment requires that the ambient temperature
in the repair shop be the same as that of the transceiver
and test equipment, and that this temperature be held
constant between 20° and 30°C (68° ~ 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 before 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.