Watchman FD-30A - Adjustment Procedures; FM Section Adjustments; FM IF and Tracking Adjustments; FM Frequency Coverage Adjustment

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FD-30A

SECTION

3

ADJUSTMENTS

Pi

ins

vrvm

@

22.5

kHz

frequency

deviation

by

400

Hz

telescopic

signal

antenna

lead

Output

level:

As

low

as

possible

e

Repeat

the

procedures

in

each

adjustment

several

times,

and

the

frequency

coverage

and

tracking

adjustments

should

be

finally

done

by

the

trimmer

capacitors.

FM

IF

Adjustment

Procedure:

FM

RF

SSG

oscilloscope

400

Hz,

30%

FM

modulated

telescopic

22.5

kHz

frequency

deviation

antenna

lead

PHONES

Output

level:

As

low

as

possible

%

10784011

A

f

SKZ

cae

a7

wi

Adjust

for

maximum

reading

on

VTVM.

FM

TRACKING

ADJUSTMENT

(range:

0.5--5

V

ac)

PHONES

Confirm

that

there

are

three

points

at

witch

a

sine

waveform

appears

when

cahnging

the

frequency

of

SSG

gradually.

Observe

the

center

of

these

three

points.

Adjust

SSG

for

maximum

waveform.

Adjust

T2

for

minimum

noise

on

the

waveform

and

maximum

level.

FM

FREQUENCY

COVERAGE

Adjust

for

maximum

reading

on

VTVM.

108.5

MHz

87.1

MHz

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