Pioneer TX-608 Manuale di servizio - Pagina 10

Sfoglia online o scarica il pdf Manuale di servizio per Amplificatore Pioneer TX-608. Pioneer TX-608 36. Stereo control amplifier
Anche per Pioneer TX-608: Manuale di istruzioni per l'uso (28 pagine)

Stampa la pagina

8. ADJUSTMENTS

8.1

FM TUNER

e Connect the FM

SG (FM signal generator) to

the

ANTENNA

30002

terminals

via a 3000

dummy antenna.

e Switch

the

FUNCTION

selector

to the FM

position,

the

MUTING

switch

to the OFF

position.

e The tuning coils in the FM front end dose not

have

adjusting

core.

Consequently,

tracking

adjustments at 90OMHz are performed by regulating

the gap between

rotor and stator

of the tuning

capacitors (VC1, VC3

and VCs).

The expression

"adjust VC (VC:i, VC3, VCs) found in the text

means

that the two outer rotor blades of each of

these

tuning capacitors are to be extended

out-

wards with spatula (Part No. GGK-066) as shown

in Fig. 8-1.

Stator

Rotor blade

| l

Stator

Rotor blade

Spatula

> fL a

(GGK-066)

Fig. 8-1 Adjustment of tuning capacitor

Set the TX-6800

dial point to a frequency in

the 106MHz

region so that there will be no

input signal.

Next tune more accurately to 1O6MHz, and set

the FM

SG output to 106MHz, 60 to 80dB

(modulation—400Hz, +75kHz deviation).

Adjust TCs

to obtain maximum

deflection of

the SIGNAL meter indicator, and a dead center

reading in the TUNING meter.

Then tune the dial pointer to 90MHz, and set

the FM SG output frequency to 90MHz.

Adjust the VCs

to obtain maximum deflection

in the SIGNAL meter, and a dead center read-

ing in the TUNING meter.

Repeat steps 3 to 6 above.

Reset the FM

output level to 20—30dB,

and

adjust

TC:

and

TCs

at 106MHz,

'and

VC:

and VCs

at 90MHz

in the same manner

as described

above in steps 3 to 7. These ad-

justments

will ensure

optimum

sensitivity in

the 90 to 106MHz

range, and minimum

dif-

ference in sensitivity between the two extreme

frequencies.

Retum to a position with no input signal.

10. Rotate

the

core

of T2

again

to set the

TUNING meter indicator to dead center.

11. Set the FM

SG output to 98MHz

and 66dB

(modulation—400Hz,

+75kHz

deviation),

and

tune the TX-6800 to this position.

12. Then

rotate

the D core of Tz to reduce dis-

tortion in the demodulator

output (OUTPUT

terminal) to a minimum.

18. Repeat steps 9 to 12 above until both specifi-

cations (center TUNING

meter reading in the

absence

input

signal,

and

minimum

dis-

tortion in demodulator output) are satisfacto-

rily met.

Multiplex Decoder

e Connect the MPX SG (FM multiplex generator)

to the FM SG external modulator terminal.

e Set the FM MUTING switch to the ON position.

14. Set the FM

output to 98MHz

and 66dB

(unmodulated),

and tune the TX-6800 to this

position.

15. Adjust VR:

to obtain a 76kHz signal at TP .

terminal,

16. Then set the FM SG output level to 86dB, and

the modulation

mode

to external.

Then with

the

MPX

SG,

set

Main

1kHz,

L+R

+67.5kHz

deviation,

and

pilot

signal

+7.5kHz deviation.

17. Rotate the T: core around by up to 90° in

either

direction

to reduce

the

demodulator

output

(OUTPUT

terminal)

distortion

to a

minimum,