Standard Horizon HX400, Service Manual

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HX400 Service Manual
Alignment
Alignment - 1
Introduction and Precautions
The HX400 has been carefully aligned at the fac -
tory for performance across the specified VHF
band. Realignment should therefore not be nec -
essary except in the event of a component fail -
ure. All component replacement and service
should be performed only by an authorized
STANDARD HORIZON representative, or the
warranty policy may be voided.
The following procedures cover the sometimes crit
-
ical and tedious adjustments that are not normally
required once the transceiver has left the factory.
However, if damage occurs and some parts are re -
placed, 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 authorized STANDARD HORIZON service
technicians, who are experienced with the circuit -
ry 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
STANDARD HORIZON service technicians 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 poli -
cy. Also, STANDARD HORIZON 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 function and opera -
tion of the transceiver are clearly understood, the
cause of the malfunction has been clearly pinpoint -
ed and any faulty components replaced, and the
need for realignment determined to be absolutely
necessary.
Required Test Equipment

RF Signal Generator with calibrated output lev -
el at 200 MHz

Avionics Radio Tester

Deviation Meter (linear detector)

In-line Wattmeter with 5% accuracy at 200 MHz

50-ohm, 10-W RF Dummy Load

8-ohm AF Dummy Load

Regulated DC Power Supply adjustable from
0 to 12 V DC, 3 A

Frequency Counter:
±
0.2 ppm accuracy at
200 MHz

AF Signal Generator

AC Voltmeter

DC Voltmeter: high impedance

VHF Sampling Coupler

SINAD Meter
Important Notice
Do not adjust the alignment menus that are
not mentioned in this manual.