Pioneer PL-L1000 Service Manual page 19

to H level.
Furthermore, when the elevator FF Q is con-
nected to pin (6) of IC18 to make Q = H (i.e. Up
-position), the monostable multivibrator is inhibit_
ed, thereby inhibiting the detector circuit. Q = H
also when the power switch is tumed on, again in-
hibiting the multivibrator.
6 . 1 . 3 E L E V A T I O N C O N T R O L S T A G E
x When the power switch is turned on,
an initial
reset sigrral is passed to pin (12) of IC14 from
R551C29, resulting in pin (11) of IC14 and pin
(14) of IC12 being switched to H level (Q = H).
This corresponds to the elevator being in the
UP position, or in other words, Up priority is
given when the power is first turned on.
* Since Q = H, one of the ICZ transistors
will
be turned on to light up the Up indicator lamp.
x Until the elevator reaches the Up position
the
UP detector switch remains in the NC position,
resulting in pins (13) and (I2) of IC1Z being
both switched to L level, and e13 and e16 of
the elevator drive stage being both turned on
to start up the motor.
x Once the elevator is properly in the Up position,
the UP detector switch is switched to the NO
position, resulting in pin (18) of IC1? being
switched to H level, and pin (11) of IC1Z being
switched to L level.
Q1B and e16 are both
turned off and the motor stopped.
x If the elevator switch is then pressed,
a falling
edge differential
pulse is generated on pins
(1) and (2) of lCL4, and a rising edge clock
pulse on pin (13) of IC12.
This results in
Q = H and Q = L for lowering of the elevator
(DN).
* And since
Q = H, the DN indicator lamp will be
lit up, and the UP indicator turned off.
x The DN detector switch remains in
the NC
position until the elevator is right down. During
this period, pins (9) and (8) of IC1T will be
both at L level, while pin (10) of IC1? will be
at H level. The elevator drive stage e14 and
Q15 will thus be on and the motor rotating.
x If the elevator switch is pressed during
this
condition, Q will switch to L and Q to H (Up)
to reverse the motor.
The above description relates to the opera_
tion of the elevator circuit itself. In addition,
* automatic mode UP (as
described under the
tonearm control stage), and
* DN at the lowering position,
may be controlled via the elevator FF preset
and clear terminals.
FL-L1 clclcl
6 . 1 . 4 R E C O R D S I Z E S E L E C T O R S T A G E
x When the power is turned on, the initial
reset
signal from P"55lC29 is passed to IC16 to
switch pin (11) to H level, resulting in IClb
being cleared.
* Pin (1) (Q1) and pin (15) (e2) of rClb
are
both switched to L level, this then being trans-
ferred to pins (8) and (9) of IC18. pin (10) of
IC18 is thus switched to H level and the BOcm
indicator lamp is lit up.
* If the size selector is then pressed, the falling
' edge differential pulse applied
to pin (18) of
IC18 when pin (12) of this IC was at L level
(i.e. when none of the lead-in, return, or repeat
modes was operative), is instead applied to pin
(11) of IC18 as a rising edge clock pulse, thereby
activating the ring counter in IC1b. As a result,
Q1 = H and Q2 = L. The BOcm indicator lamp
is turned off, and the 2bcm indicator lamp
turned on.
* If the size selector is pressed
again, the 17cm
indicator lamp is turned on.
Every time the
selector is pressed, the size is switched in a
cyclic order 30 --> 25 -> L7.
6 . 1 . 5 R E P E A T C O N T R O L S T A G E
* When the power is turned on,
the intial reset
signal from R55/C29 is applied to pin (g) of
ICI4, resulting in pin (10) of this IC being
switched to H level, and pin (1) (e) of. lCL2
being switched to L level.
* The repeat indicator lamp will
thus be turned
o f f ( s i n c e Q = L ) .
x If the repeat switch is then pressed,
a falling
edge differential pulse will be applied to pins
(5) and (6) of lCL7, and a rising edge clock
pulse generated at pin (4).
As long as the
repeat or return modes are not operative at
this time, pin (5) (K) and (6) (J) of IC12 will
both be at H level, resulting in e - H, and Q
= L for the repeat indicator to be
turned on.
At the same time, pin (13) of IC13 is switched
to L level, thereby enabling the monostable mul-
tivibrator consisting of 2 gate circuits in IC1B
to operate during repeat.
x If the repeat switch is then pressed
again, the
J = K = H status will be inverted.
In addition to the above repeat control stage,
x The START/STOP switch may be pressed
to
activate return mode.
In this case, a falling
edge pulse is generated on pin (4) of IC10,
and then applied to pin (S) of ICL . pin
(10) of IC14 is thus switched to H level, and
the IC12 FF cleared (repeat off), resulting in
Q = L a n d Q = H .