Pioneer PL-L1000 Service Manual page 17

* Number in parenthesis are the IC pin numbers.
x L d e n o t e s L l e v e l .
* H d e n o t e s H l e v e l -
* EV denotes arm elevator, UP denotes that arm
elevator is in UP position, while DN that
elevator is in the DOWN position.
The Full Auto Logic section is made up of the
following 5 main stages.
(1) Tonearm control stage
(2) End detector stage
(3) Elevation control stage
(4) Record size selector stage
(5) Repeat control stage
6 . 1 . 1 T O N E A R M C O N T R O L S T A G E
1. When the power switch is turned on . . . .
. . . . the lead-in FF and retum FF are reset
by the initial reset signal (passed from
C29lF-55 to IC16,-+ICI7,->IC9, and IC10).
. . . . the phono motor will remain stationary
if the tonearm is on the arm rest, but
commence to rotate if it has alreadv been
moved away.
2. When the START/STOP switch is then pressed
with the tonearm on the arm rest,
* Pin (8) of IC8 is switched to L level.
* Pin (10) of IC8 is switched to H level, and this
appears at pin (3) of IC10, resulting in the
lead-in FF being set (and pin (10) of IC10 also
being switched to H level).
* Once pin (10) of IC10 is switched to H level,
pin (3) of IC8 is switched to L level, resulting
in pin (8) of IC1L being likewise switched to
L level, thereby inhibiting manual drive (locate
operation).
Pin (13) of IC14 is also switched to L level,
resulting in pin (12) of IC12 being switched to
H level, and the elevator being consequently
raised to the UP position.
* Pin ( ) of IC11 is switched to H level, result-
ing in the inhibition of any further START/
STOP switch inputs after a delay of about lms
(in order to prevent the return FF from being
set when the tonearm leaves the arm rest). At
the same time, pin (12) of IC18 is switched to
H level to inhibit switching of the size selector.
Hence, the relevant FFs are set, the arm
elevator raised, and record size selector switch-
ing inhibited.
PL-L1 clc'cl
Pin (11-) of IC10 is switched to L, and this is
transferred to pin (6) of ICS. Once the elevator
is properly in the UP position, the UP detector
switch is switched to the NO position, resulting
in pin (5) of IC8 being switched to L level, and
pin (4) of IC8 switched to H level.
This IC8 pin (4) H level signal then turns Q7 on,
resulting in a current being passed from VR8 to
VRb and R99 via R93. If the potential at TP8
drops below the potential at TP10, the dif-
ference is amplified
and a current passed
through the coil to subsequently drive the
czrlrier.
The carrier is thus shifted across towards
the record. (Assume size selector set to 30cm).
When the carrier reaches a position about 20mm
in front of the 30cm position, the carrier shutter
will block the light of the 30cm sensor.
Pin (13) of IC9 is thereby switched to L level,
and pin (10) of IC9 switched to H level. This
serves as a trigger for the monostable multivi-
brator incorporated in IC13, resulting in the
generation of an H level signal of r = 2.2 sec.
This is applied to TP3 and pin (9) of lCL2,
presetting the EV FF for lowering of the tone-
arm.
The TPB H level signal is used to drive IC7, and
in turn attracts the plunger and raise the index
plate.
The carrier continues to move further, com-
ing to a stop when the swing pin strikes the
index plate.
TP3 is switched back to L level 2.2 seconds
later, the signal being differentiated by C34
and R44 to provide the tonearm descend signal
which is passed via IC1-7, IC9 and IC10 to
clear the FFs and stop the carrier drive current.
The elevator UP, locate inhibition, and size
selector switching inhibition are dlso cancelled
at the same time.
As a further result of TPB being switched to L
level, the charge held by C35 is discharged via
R43 and the IC7 base resistance. During this
discharge period (0.3 to 0.5 sec.) the plunger
is maintained in the attracted position, but is
forced back (by a spring) once the discharge
has been eompleted.
The elevator is thereby
retumed to DOWN position for start of play.