EVX-531 UHF Service Manual
11
Introduction
The
EVX-531
series has been aligned at the factory for the
specified performance across the entire frequency range spec-
ified. Realignment should therefore not be necessary except
in the event of a component failure. All component replace-
ment 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 operation, it is likely
due to component failure; realignment should not be done un-
til after the faulty component has been replaced.
We recommend that servicing be performed only by autho-
rized Vertex Standard service technicians who are experi-
enced with the circuitry and fully equipped for repair and
alignment. Therefore, if a fault is suspected, contact the deal-
er from whom the transceiver was purchased for instructions
regarding repair. Authorized Vertex Standard service techni-
cians realign all circuits and make complete performance
checks to ensure compliance with factory 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 procedures in the interest of improved perfor-
mance, without notifying owners. Under no circumstances
should any alignment be attempted unless the normal func-
tion and operation 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
determined to be absolutely necessary. The following test
equipment (and thorough familiarity with its correct use) is
necessary for complete realignment. Correction of problems
caused by misalignment resulting from use of improper test
equipment is not covered under the warranty policy. While
most steps do not require all of the equipment listed, the inter-
actions of some adjustments may require that more complex
adjustments be performed afterwards. Do not attempt to per-
form 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.
Alignment
Required Test Equipment
r
Radio Tester with calibrated output level at 600 MHz
r
In-line Wattmeter with 5% accuracy at 600 MHz
r
50-, 10-W RF Dummy Load
r
Regulated DC Power Supply (standard 7.5 VDC, 3 A)
r
Frequency Counter: ±0.2 ppm accuracy at 600 MHz
r
AF Signal Generator
r
AC Voltmeter
r
DC Voltmeter
r
UHF Sampling Coupler
r
IBM PC/Compatible Computer with Microsoft
®
Win-
dows
®
2000, XP, Vista, or 7
r
Vertex Standard CE142 PC Programming Software
r
Vertex Standard FIF-12 USB Programming Interface and
CT-106 PC Programming Cable
r
Vertex Standard FRB-6 Tuning Interface Box and CT-160
Connection Cable
Alignment Preparation & Precautions
A 50- RF Dummy 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. Correct
alignment is not possible with an antenna.
After completing one step, read the following step to deter-
mine whether the same test equipment will be required. If not,
remove the test equipment (except dummy load and wattme-
ter, if connected) before proceeding.
Correct alignment requires that the ambient temperature be
the same as that of the transceiver and test equipment, and
that this temperature be held constant between 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 tempera-
ture before alignment.
Whenever possible, alignments should be made with oscilla-
tor shields and circuit boards firmly affixed in place. Also, the
test equipment must be thoroughly warmed up before begin-
ning.
Note
: Signal levels in dB referred to in this procedure are
based on 0 dBµ EMF = 1.0 µV.
Test Setup
Setup the test equipment as shown below for transceiver
alignment, then apply 7.5 V DC power to the transceiver.
Inline
Wattmeter
50-ohm
Dummy Load
RF Signal
Generator
AF Signal
Generator
SINAD Meter
Power Supply
7.5 VDC
Computer
(CE142)
FRB-6
Deviation
Meter
Frequency
Counter
Transceiver
MIC/SP
D-Sub 15-pin
Connector
MIC IN
SP OUT B
CT-160
SP/LOAD Switch: LOAD
LOAD Switch: 16
Battery Terminal
CLONE Port
CT-104A, CT-106, or CT-171
ANT
Sampling
Coupler
FIF-12
