Yaesu VX-3R Сервис-мануал - Manual (Page 9)

9
Alignment
Introduction
The VX-3R is carefully aligned at the factory for the
specified performance across the amateur band. Realign-
ment should therefore not be necessary except in the event
of a component failure. Only an authorized VERTEX
STANDARD representative should perform all compo-
nent replacement and service, or the warranty policy may
be void. The following procedures cover adjustments that
are not normally required once the transceiver has left
the factory. However, if damage occurs and some parts
are subsequently replaced, realignment may be required.
If a sudden problem 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. 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. If a fault is suspected, contact
the dealer from whom the transceiver was purchased for
instructions regarding repair. Authorized VERTEX STAN-
DARD 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 align-
ments are cautioned to proceed at their own risk. Prob-
lems caused by unauthorized attempts at realignment are
not covered by the warranty policy. In addition, VERTEX
STANDARD reserves the right to change circuits and
alignment procedures in the interest of improved perfor-
mance, without notifying owners.
Under no circumstances should any alignment be at-
tempted unless the normal function and operation of the
transceiver is clearly understood, the cause of the mal-
function has been clearly pinpointed, any faulty compo-
nents are replaced, and realignment is determined to be
absolutely necessary.
The following test equipment (and familiarity with its
use) is necessary for complete realignment. Correction of
problems caused by misalignment resulting from use of
improper test equipment is not covered under the war-
ranty policy. While most steps do not require all of the
equipment listed, the interactions of some adjustments
may require that additional adjustments be performed.
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 section in the order presented.
Required Test Equipment
P RF Signal Generator with calibrated output level at 500 MHz
P Deviation Meter (linear detector)
P In-line Wattmeter with 5% accuracy at 500 MHz
P 50-ohm, 10-W RF Dummy Load
P 8-ohm AF Dummy Load
P Regulated DC Power Supply adjustable from 3 to 15 V DC, 3A
P Frequency Counter: 0.2-ppm accuracy at 500 MHz
P AF Signal Generator
P AC Voltmeter
P DC Voltmeter: high impedance
P UHF Sampling Coupler
P SINAD Meter
Alignment Preparation & Precautions
A 10 W RF dummy load and in-line wattmeter must
be connected to the main antenna jack in all procedures
that call for transmission, alignment is not possible with
an antenna. After completing one step, read the next step
to see if the same test equipment is required. If not, re-
move the test equipment (except dummy load and watt-
meter, if connected) before proceeding.
Correct alignment requires that the ambient tempera-
ture of the transceiver be the same as that of the test equip-
ment, and that the temperature be held constant between
68 ~ 86 °F (20 ~ 30 °C). When the transceiver is brought
into the shop from hot or cold air, it should be allowed
some time to come to room temperature before alignment.
Whenever possible, alignments should be made with os-
cillator shields and circuit boards firmly affixed in place.
The test equipment must be thoroughly warmed up be-
fore beginning.
Note: Signal levels in dB referred to in the alignment procedure
are based on 0 dBμ=0.5 μV (closed circuit).
Test Setup
Set up the test equipment as shown below for transceiv-
er alignment, and apply 4.4 V DC power to the transceiver.
Refer to the drawings for Alignment Points.
Alignment Setup
Wattmeter
In-Line
Dummy Load
50-ohm RF
Coupler
Sampling
Meter
Deviation
Counter
Frequency
Generator
RF Signal
Meter
SINAD
AF Load
8-ohm