Table of Contents
Advertisement
I
B L O C K D I A G R A M O P E R A T I O N S
5.1
TONEARM CONTROL STAGE
a. Lead-in FF and Return FF
Lead-in FF . . . . This FF is set by pressing the
S/S (START/STOP) switch
when the tonearm is on the
arm rest, and is reset by a
descend signal, or when the
power switch is turned on.
Return FF . . . . This FF is set by pressing the
S/S switch when the tonearm
is not on the arm rest, and
also by the end detector. It
is reset when the power is
turned on, or by the descend
signal, or when the tonearm
returns
to
the arm rest.
b. When either of the above 2 FFs has been ser, an
"AUTO
on"
signal is generated (as well as
AUTO on), resulting in the arm elevator being
set to the UP position, and inhibition of manual
drive.
5.2
END DETECTOR STAGE
The end sensor input signal is rectified and then
applied to the detector stage consisting of a dif-
ferential circuit, integration circuit, and a mono-
stable multivibrator.
When the detector stage detects the arrival of 2
consecutive input signals within the fixed time
constant period, an output signal is generated.
This output, however, is inhibited by the EV Up
signal when the arm elevator is in the Up position.
O U T P U I
E V u p s q n a
F i g . 5 _ 1
5.3
ARM ELEVATION CONTROL STAGE
This stage consists of a J-K-type FF with a reset
(clear) input and preset input.
The arm elevator is raised (Up position) as a
result of the initial resetting, or by the AUTO
operation signal from the tonearm control stage.
The eleyator descend again (DOWN position)
when the FF is preset by the descend signal.
Furthermore, whenever the EV switch is pressed,
Q and Q are generated alternately, resulting in the
arm elevator being raised and lowered correspond-
ingly.
The FF output is applied to a logical ,,and"
circuit with the outputs from the elevator Up and
DOWN switches, the resultant output being applied
to the EV motor drive stage.
s.iA SIZE SELECTOR STAGE
This stage consists of a J-K FF 2-stage ring
counter and the QUQ2 logical ,,and,' gate. As a
result of the initial resetting, Ql = Q2 = L for auto-
matic switching of the size selector to the B0cm
position.
Every time the size selector switch is
pressed after that, the selector is switched from
the 30 to 25 and 17 positions in turn, and then
back to 30 again. Note, however, that switching
is inhibited when AUTO operation signals are
received from
the tonearm control stage (i.e.
during lead-in, return, and repeat operations).
5 . 5
R E P E A T C O N T R O L S T A G E
Consisting of a T-type FF, e and Q are inverted
by Repeat switch operation. Note that the FF is
also turned off by the initial reset, and that there
is no inversion while the tonearm control stage
return FF remains set (i.e. during return and
repeat operations).
Furthermore. the FF is also
turned off as a result of auto-cut operation during
repeat mode.
5 . 6
L O W E R I N G
P O S I T I O N
D E T E C T O R ,
P L U N G E R
C O N T R O L
S T A G E ,
A N D
D E S C E N D S I G N A L G E N E R A T O R
When the tonearm shutter passes between the
sensors corresponding to the designated record
size (sensors being mounted in positions corres-
ponding to each record size), a lowering position
detector output signal is generated. This signal is
then applied to the plunger control stage (a mon-
stable multivibrator),
resulting in a fixed time
constant pulse signal being generated to activate
the plunger (during lead-in and repeat modes).
The down stroke of the pulse signal is differentiat-
ed and a descend position signal generated. Each
of the tonearm control stage FFs is also cleared.
5 . 7
D I S P L A Y S T A G E A N D P L U N G E R
D R I V E R
This stage is responsible for the LED display
of elevator position, repeat mode, and selected
record size, in addition to plunger drive.
5.8
By
motol
senso
f,onea
opera
is DC
return
5.9
Thr
CdS r
voltag
ment.
the d
to pa
the to
EITOT
senso
./
7
V
\
Hide quick links:
Advertisement
Table of Contents
