9
FT-277R Technical Supplement
Alignment
Introduction
The
FT-277R
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 Stan-
dard representative should perform all component re-
placement and service, or the warranty policy may be
void.
The following procedures cover the adjustments that are
not normally required once the transceiver has left the fac-
tory. However, if damage occurs and some parts subse-
quently are replaced, realignment may be required. If a
sudden problem occurs during normal operation, it is like-
ly 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 au-
thorized Vertex Standard service technicians who are ex-
perienced 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 Standard service tech-
nicians 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
reserves the right to change circuits and alignment proce-
dures in the interest of improved performance, without
notifying owners.
Under no circumstances should any alignment be attempt-
ed unless the normal function and operation of the trans-
ceiver are clearly understood, the cause of the malfunc-
tion has been clearly pinpointed and any faulty compo-
nents replaced, and realignment determined to be abso-
lutely necessary.
Required Test Equipment
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 more complex adjustments be per-
formed afterwards.
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.
RF Signal Generator with calibrated output level at 500
MHz
Deviation Meter (linear detector)
In-line Wattmeter with 5% accuracy at 500 MHz
50-Ohm 10-W RF Dummy Load
8-Ohm AF Dummy Load
Regulated DC Power Supply adjustable from 6 to 15
VDC, 2A
Frequency Counter: 0.2-ppm accuracy at 500 MHz
AF Signal Generator
AC Voltmeter
DC Voltmeter: high impedance
UHF Sampling Coupler
SINAD Meter
Alignment Preparation & Precautions
A 50-Ohm RF load and in-line wattmeter must be con-
nected 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, 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
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.
Also, the test equipment must be thoroughly warmed up
before beginning.
Note
: Signal levels in dB referred to in the alignment pro-
cedure are based on 0dBµ = 0.5µV.
