Vertex Standard VX-900 - Manual (Page 20)

20
Alignment
Introduction
The VX-900 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 when altering the ver-
sion type. All component replacement and service
should be performed only by an authorized VER-
TEX STANDARD
representative, or the warranty
policy may be voided.
The following procedures cover the sometimes criti-
cal 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 placed, 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 replaced.
We recommend that servicing be performed only
by authorized VERTEX STANDARD service techni-
cians who are experienced with the circuitry and
fully equipped for repair and alignment. 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
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 opera-
tion of the transceiver are clearly understood, the
cause of the malfunction has been clearly pinpointed
and any faulty components replaced, and realign-
ment determined to be absolutely necessary.
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 pre-
sented.
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 listed,
the interactions of some adjustments may require
that more complex adjustments be performed after-
wards.
Required Test Equipment
r
RF Signal Generator with calibrated output level
at 600 MHz
r
Deviation Meter (linear detector)
r
In-line Wattmeter with 5% accuracy at 600 MHz
r
50-Ohm RF Dummy Load with power rating 10W
at 600 MHz
r
16-Ohm AF Dummy Load
(Attention : Audio output is BTL output; do not
short "shield" to ground!)
r
Regulated DC Power Supply (standard 7.5V DC,
3A)
r
Frequency Counter with 0.2 ppm accuracy at 600
MHz
r
AC Voltmeter
r
DC Voltmeter
r
UHF Sampling Coupler
r
IBM PC / compatible Computer with Microsoft
DOS v3.0 or later operating system
r
Vertex Standard CT-71 Connection Cable and
SVC39 Alignment program
Alignment Preparation and Precautions
A 50-Ohm RF Dummy Load and in-line wattmeter
must be connected to the main antenna jack in all
procedures that call for transmission, except where
specified otherwise. Correct alignment is not pos-
sible 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 (ex-
cept dummy load and wattmeter, in connected) be-
fore 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 20° and 30° C (68 ° ~ 86 ° F). When
the transceiver is brought into the shop from hot or
cold air, it should be allowed time to come to room
temperature before alignment.