Pioneer A-X700 Servis Kılavuzu - Sayfa 10

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Automatic Function Switching

If audio components featuring "'one-touch auto-

play"?

functions

are

connected

to the

relevant

PHONO

(PL), TUNER

(TX), CD, or TAPE1(CT)

"AUTO

FUNCTION"

terminal on the rear panel

of the A—X700,

the function

is switched

auto-

matically to the operated component.

When the PLAY or STATION

CALL switch of

the component connected to the PHONO, TUNER,

CD, or TAPE1 terminal is switched on, the generat-

ed L level signal is passed to the microcomputer

which

in turn passes

corresponding

data to the

function

switch

(TC9162N)

to effect the actual

switching operation.

Stop Signal

When a function is switched by automatic func-

tion switching or amplifier function switching, an

H level signal is generated at pin 30 of the micro-

computer.

Q301

is thus turned on, and auto stop

output signals are passed to PL, CD, and CT.

Double Deck and Single Deck Switching

S301 is switched according to whether the tape

deck connected

to TAPE1

is a double

or single

deck. When a double deck is used, S301 is switched

resulting in pin 25 of the microcomputer

re-

maining

at H level. Q404 is thus turned on, and

Q406 then Q102 are turned off. When Q101 and

Q102 are both turned off, REC1 is switched on.

When S301 is off, pin 25 of the microcomputer

is switched to H or L level depending on whether

or not function has been switched to TAPE1.

the function has been switched to TAPE1, pin 25

is switched to L level, resulting in Q101 and Q102

being

turned

and REC1

being switched

off.

When

the function is switched to other positions,

the reverse occurs.

Remote Control Terminal

The photosensitive section of the remote control

mechanism is located in the tuner. Upon reception

of a remote control signal in the tuner,

a VR UP,

DOWN,

muting,

VIDEO/AUX,

or tuntable start/

stop signal is decoded by the microcomputer. Re-

mote control signals for CD or TAPE]

are passed

direct from the tuner.

Microcomputer Reset Circuit

+17V(B2)

Q4ot

c401

+5.6V(B1)

[

S76

V(B

R405

Fig. 7-8

= Se

B2 voltage

§.5-—-——-—- 7

Q401 collector

7.4

B1 voltage

eee

Q403 base

; =r. —

0403 collector

Fig. 7-8-1

The

microcomputer reset circuit is outlined in

Fig. 7.7.

When

the power

is switched

on, and the Q401

base voltage

(B,) is increased

to 5.6V

with the

emitter voltage

(B,) in excess

of 7.4V, Q401 is

turned on and the collector voltage is gradually in-

creased to 15.5V. The Q401 output is differentiat-

ed by C401/R405

and then inverted by Q403 to

obtain the reset signal.

D425 has been inserted in the circuit to prevent

Q408 cut-off at the same time the power is switch-

ed off in order to prevent the memory from being

switched

off by reset circuit misoperation if the

power switch is switched on and off in quick suc-

cession. The reset signal resets the microcomputer

once clock oscillation (3.84 MHz) has been com-

menced when the STANDBY

pin (No.37) voltage

is increased after the power is switched on.

PD6027 Functions

Ene

eS 3.84 MHz resonator is connected

} 2]

x | between these pins.

3 | RESET]

Positive power supply (VOD) connection

Remote control signal input

Serial data output to PD0012, TC9177P,

and TC9162N.

SC/Arg

l=[=[=[ele]e[e]

Output of key matrix

drive signals

TAPE 1

| n

Indicator outputs

m) ow] mle

coy"

elelele]

[=] =] =| =|

Strobe outputs

25°| R i

TAPE 1

110W meter range

Back-up mode starter input

Auto function input

b be]

NTH

w Oo

Indicator

outputs

EEEEEGG

Key inputs

u ne

Nefelefe}e]

= ] e ]

ies)

*Pin No. 25.

The R12 pin is at H level. Pin 25 is switched to

L level when

TAPE1

function is selected, but is

switched to H level in other function positions, and

R12 remains at H level.

*Pin No. 30

Switched

to H level for 100msec

immediately

following function switching.