Vertex Standard VXA-150 Manuel de service télécharger pdf (Page 14)

Radio Tester

In-line Wattmeter

50- RF Load

AF Signal Generator

AC Voltmeter

REG. 7.2VDC P.S.

Frequency Counter

RF Sampling Coupler

SPL

BEEP

SKIP

ANL

5 6

121.5

Alignment

Alignment Setup

The VXA-150 is carefully aligned at the factory for the

specified performance across the Aircraft and Weather

bands. Realignment should therefore not be necessary

except in the event of a component failure.

The following procedures cover the adjustments that

are not normally required once the transceiver has left the

factory. However, if damage occurs and some parts sub-

sequently 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

authorized Vertex Standard service technicians who are

experienced with the circuitry and fully equipped for re-

pair and alignment. If a fault is suspected, contact the deal-

er from whom the transceiver was purchased for instruc-

tions regarding repair. Under no circumstances should any

alignment be attempted unless the normal function and

operation of the transceiver are clearly understood, the

cause of the malfunction has been clearly pinpointed and

any faulty components replaced, and realignment deter-

mined to be absolutely necessary. Problems caused by un-

authorized attempts at realignment are not covered by the

warranty policy.

Vertex Standard reserves the right to change circuits

and alignment procedures, in the interest of improved per-

formance, without notifying owners.

The following test equipment (and familiarity with its

use) is necessary for complete realignment. While most

steps do not require all of the equipment listed, the inter-

actions of some adjustments may require that more com-

plex adjustments be performed 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.

Correction of problems caused by misalignment result-

ing from use of improper test equipment is not covered

under the warranty policy.

Note:Signal levels in dB reffered to in this procedure are

based on 0 dBµ = 0.5 µV (closed circuit).

Required Test Equipment

¦ Radio Tester with calibrated output level at 200

MHz

¦ In-line Wattmeter with 5% accuracy at 200 MHz

¦ 50-W, 10-W RF Dummy Load

¦ Regulated DC Power Supply adjustable from 3 to

15 VDC, 2A

¦ Frequency Counter: ±0.2 ppm accuracy at 200 MHz

¦ AF Signal Generator

¦ AC Voltmeter

¦ DC Voltmeter: high impedance

¦ VHF Sampling Coupler

Alignment Preparation & Precautions

A 50-W RF 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. Cor-

rect alignment is not possible with an antenna. After com-

pleting 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.

Set up the test equipment as shown below for trans-

ceiver alignment, apply 7.2 VDC power to the transceiv-

er. Refer to the drawings for Alignment Points.

1 2 ... 9 10 11 12 13 14 15 16 17 18 19 ... 31 32

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Vertex Standard VXA-150 Manuel de service Page 14

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