Yaesu FT-712RH, Technical Supplement

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Alignement
r
The high reliability of the chip components
in the FT-712RH m i n i m i z e the possibility
that repair or realignment should be needed
after leaving the factory. However, if
damage occurs and some parts subsequently
be replaced, realignment may be required.
If a sudden problem occurs during normal
operation, it is likely due to component
f a i l u r e ; r e a l i g n m e n t should not be done
u n t i l after the faulty component has been
replaced.
Because of the compact circuitry of this
transceiver, we recommend that servicing be
performed only by authorized Yaesu service
technicians who are experienced with the
circuitry and fully equipped for repair and
alignment. Therefore, if a fault is suspected,
contact the dealer from whom the transcei-
ver was purchased for instructions regarding
repair. Authorized Yaesu service technicians
realign all circuits and make complete per-
formance checks to ensure compliance with
factory specifications after replacing any
faulty components.
Those who do undertake any of the follow-
ing alignments are cautioned to proceed at
their own risk. Yaesu must reserve the
r i g h t to c h a n g e circuits and alignment
p r o c e d u r e s in the interest of improved
performance, without notifying owners.
No alignment should be attempted unless
the normal function and operation of the
t r a n s c e i v e r are clearly understood, the
cause of the malfunction has been clearly
p i n p o i n t e d and any faulty components re-
placed, and the need for realignment deter-
mined to be absolutely necessary.
The following test equipment (and thorough
familiarity with its correct use) is necessary
f o r complete realignment. Correction of
problems caused by misalignment resulting
from use of improper test equipment is not
covered under the warranty policy.
A 50-ohm dummy load that is non-reactive
up to 500 MHz is required. Correct align-
ment is not possible with an antenna.
Alignment Equipment
DC voltmeter (at least 20-kilohms/volt)
500 MHz standard signal generator (SSG)
with calibrated level and modulation (see
note below)
AF signal generator
SINAD meter (SINADDER)
FM linear detector (deviation meter)
CM coupler (directional coupler)
RF wattmeter (50W, ±5% @ 500MHz)
50-ohm non-reactive (@500 M H z ) dummy
load
Frequency counter ( l O O H z resolution at
500MHz)
Oscilloscope (recommended, not required)
Note: SSG levels referred to in the align-
ment procedure are based on OdBu=0.5uV.
Alignment Precautions
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 and 30 °C (68 to 86 °F). When the trans-
ceiver is brought into the shop it should be
allowed at least 2 hours for thermal equal-
ization before alignment.
Alignments must not be made unless the
oscillator shields and circuit boards are
firmly affixed in place. Also, the frequency
c o u n t e r must be thoroughly warmed up
before beginning.
Supply voltage during alignment must be
held constant at 13.8V DC. Use a well regu-
lated, adjustable power supply capable of at
least 10A continuous load.
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