Alignment - Vertex Standard VX-800 Service Manual

Alignment

Introduction
The VX-800 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 version
type. All component replacement and service should
be performed only by an authorized Vertex Stan-
dard representative, or the warranty policy may be
void.
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 technicians
who are experienced with the circuitry and fully
equipped for repair and alignment. Those who do
undertake any of the following alignments are cau-
tioned to proceed at their own risk. Problems caused
by unauthorized attempts at realignment are not
covered by the warranty policy. Also, Vertex Stan-
dard reserves the right to change circuits and align-
ment procedures, in the interest of improved per-
formance, 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-
18
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
RF Signal Generator with calibrated output level
at 1000 MHz
Deviation Meter (linear detector)
In-line Wattmeter with 5% accuracy at 1000 MHz
50-Ω RF Dummy Load with power rating 10W at
1000 MHz
16-Ω AF Dummy Load
(Attention : Audio output is BTL output; do not
short "shield" to ground!)
Regulated DC Power Supply (standard 7.5V DC,
3A)
Frequency Counter with 0.2 ppm accuracy at 1000
MHz
AC Voltmeter
DC Voltmeter
VHF Sampling Coupler
IBM PC / compatible Computer with Microsoft
DOS v3.0 or later operating system
Vertex Standard CT-71 Connection Cable and
SVC31 Alignment program
Alignment Preparation and Precautions
A 50-Ω RF Dummy Load and in-line wattmeter must
be connected to the main antenna jack in all proce-
dures that call for transmission, except where speci-
fied otherwise. Correct alignment 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 (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 68 °F ~ 86 °F (20°C and 30°C).
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.