Alignment - Vertex Standard VXA-210 Service Manual

Introduction
The VXA-200 is carefully aligned at the factory for
the specified performance across the Aircraft and Weath-
er bands. Realignment should therefore not be necessary
except in the event of a component failure.
The following procedures cover the adjustments that
are not normally required once the transceiver has left the
factory. However, if damage occurs and some parts sub-
sequently are 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 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. If a fault is suspected, contact
the dealer from whom the transceiver was purchased for
instructions regarding repair. Under no circumstances
should any alignment be attempted unless the normal func-
tion and operation of the transceiver are clearly under-
stood, the cause of the malfunction has been clearly pin-
pointed and any faulty components replaced, and realign-
ment determined to be absolutely necessary. Problems
caused by unauthorized attempts at realignment are not
covered by the warranty policy
VERTEX STANDARD reserves the right to change
circuits and alignment procedures, in the interest of im-
proved performance, without notifying owners.
The following test equipment (and familiarity with its
use) is necessary for complete realignment. While most
steps do not require all of the equipment listed, the inter-
actions of some adjustments may require that more com-
plex adjustments be performed afterwards. Do not attempt
to perform only a signal 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.
Correction of problems caused by misalignment result-
ing from use of improper test equipment is not covered
under the warranty policy.
Required Test Equipment
r Avionics Radio Tester with calibrated output level at
200 MHz
r In-line Wattmeter with 5% accuracy at 200 MHz
r 50-W, 10-W RF Dummy Load
r Regulated DC Power Supply adjustable from 3 to 15
VDC, 2A
r Frequency Counter: ±0.2 ppm accuracy at 200 MHz
r AF Signal Generator
r AC Voltmeter
r DC Voltmeter: high impedance
r VHF Sampling Coupler
Alignment Preparation & Precautions
A 50-W RF load and in-line wattmeter must be con-
nected to the main antenna jack in all procedures that call
for transmission, except where specified otherwise. Cor-
rect alignment is not possible with an antenna. After com-
pleting one step, read the next step to see if the same test
equipment is required. If not, remove the test equipment
(except dummy load and wattmeter, if connected) before
proceeding.
Correct alignment requires that the ambient tempera-
ture be the same as that of the transceiver and test equip-
ment, and that this temperature be held constant between
20 ~ 30° C (68 ~ 86° F). 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.
Also, the test equipment must be thoroughly warmed up
before beginning.
Set up the test equipment as shown below for trans-
ceiver alignment, apply 7.2 VDC power to the transceiv-
er. Refer to the drawings for Alignment Points.
Notes: Signal levels in dB referred to in alignment are
based on 0 dBµ = 0.5 µV (closed circuit).
In-line Wattmeter
RF Sampling Coupler
Frequency Counter
1
4
7
MW
Alignment Setup

Alignment

W
50- RF Load
Radio Tester
AF Signal Generator
AC Voltmeter
3
2
REG. 7.2VDC P.S.
5 6
8 9
0 F
13