Yaesu FT-950, Technical Supplement

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ALIGNMENT-1
Alignment
FT-950 Technical Supplement
Introduction and Precautions
The following procedures cover adjustments that are
not normally required once the transceiver has left
the factory. However, If a problem occurs during
normal operation due to component failure; realign-
ment may be required after the faulty components
have been replaced.
We recommend that authorized Vertex Standard
Technicians, who are experienced with the circuitry
and fully equipped to repair and align our products,
perform repairs. If a fault is suspected, contact the
selling dealer for instructions regarding repair. Au-
thorized Vertex Standard Technicians have the lat-
est information to align all circuits and make com-
plete performance checks to ensure compliance with
factory specifications after repairs.
Those who do undertake any of the following align-
ments are cautioned and proceed at their own risk.
Problems caused by unauthorized attempts at re-
alignment are not covered by the warranty policy.
Vertex Standard must reserve 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 functions and opera-
tion of the transceiver are clearly understood, the
cause of the malfunction has been clearly identified
and all faulty components replaced. The need for
realignment should be determined to be absolutely
necessary.
The following test equipment (and a thorough fa-
miliarity with its correct use) is necessary for correct
realignment. Most steps do not require all of the
equipment listed. The interactions of some adjust-
ments may require that more complex adjustments
be performed in a sequence. Do not attempt to per-
form only a single step unless it is clearly isolated
electrically from all other steps. Have all test equip-
ment ready before beginning, and follow all of the
steps in a section in the order they are presented.
Required Test Equipment
ˆ
RF Signal Generator
ˆ
AF Signal Generator
ˆ
Spectrum Analyzer good to at least 1 GHz.
ˆ
Frequency Counter
ˆ
SINAD Meter
ˆ
RF Millivoltmeter
ˆ
Electronic Load
ˆ
Digital DC Voltmeter (high-Z, 1 M-Ohm/V)
ˆ
DC Voltmeter
ˆ
DC Ammeter (20 A)
ˆ
Ohmmeter
ˆ
DMU-2000 Data Management Unit
ˆ
50-Ohm Dummy Load (100 watts)
ˆ
In-Line Wattmeter (100 watts, 50-Ohm)
ˆ
Linear Detector
ˆ
RF Coupler
ˆ
4-Ohm AF Dummy Load (3 watts)
ˆ
1/4-inch 3-contant Plug
Alignment Preparation & Precautions
A 50-ohm RF Dummy load and in-line wattmeter
must be connected to the “ANT 1” 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 unneeded test equip-
ment before proceeding. (except the dummy load
and wattmeter).
Correct alignment requires that the ambient temper-
ature be maintained constant between 68 °F ~ 86 °F
(20 °C ~ 30 °C). When the transceiver is brought into
the shop from a hot or cold environment, it should
be allowed time to come to room temperature be-
fore alignment. Also, the test equipment must be
thoroughly warmed up before beginning.
Whenever possible, alignments should be made with
oscillator shields and circuit boards firmly affixed in
place.
Note : Signal levels in dB referred to in this proce-
dure are based on 0 dBµ = 0.5 µV (closed cir-
cuit).
Important Notice
Do not adjust the alignment menus that are not
mentioned in this manual.