Pioneer PL-V70 User manual

VY) PIONEER’
Service
CIRCUIT DESCRIPTIONS
REPAIR & ADJUSTMENTS ORDER NO.
ARP-759-0
STEREO TURNTABLE
L-V'70 (BK)
PL-LSO (BK)
@ This service manual is applicable to the PL-V70/KU and PL-L90/KU.
@ PL-L90 is the same as the PL-V70 except for exterior design .
CONTENTS
1. SPECIFICATIONS ...............0000 0a 2 B. PACKING 5. scsi e eee ea ea 40
2. FRONT PANEL FACILITIES............... 3 9, P.C. BOARDS CONNECTION DIAGRAM ..... 41
3. BLOCK DIAGRAM ............00c ce eeee 5 10. SCHEMATIC DIAGRAM.............000005 45
4. CIRCUIT DESCRIPTIONS...............5. 7 11, ELECTRICAL PARTS LIST... ........004- 47
5. DISASSEMBLY .......... 0.00000 eee 32 12. ADJUSTMENT ......... ce eee eee eens 49
6. PARTS LOCATIONS ..............0000 35 13. TROUBLESHOOTING ............000 cee 53
7. EXPLODED VIEW AND PARTS LIST........ 37
PIONEER ELECTRONIC CORPORATION 34-1, Meguro 1-Chome, Meguro-ku, Tokyo 153, Japan
PIONEER ELECTRONICS [USA] ING. P.O. Sox 1760, Long Beach, California 90801 U.S.A.
TEL: (B00) 421-1404, (B00} 237-0424
PIONEER
ELECTRONIC
(EUROPE)
N.V.
Keetberglasn
1,2740
Beveren,
Belgium
TEL:
03/775-28:08
PIONEER ELECTRONICS AUSTRALIA PTY. LTD. 178-184 Soundary Road, Braeside, Victoria 3195, Australia
TEL: [phone]
PIONEER VIDEO, INC. 200 West Grand Ave., Montvale, N.J. 07645, U.S.A. TEL: (B00) 421-1404, (B00) 237-0424
FZ © APR. 1985 Printed in Jar

PL-V70,PL-LSO
1. SPECIFICATIONS
Motor and Turntable
Drive SYSteM .......c.ccesceceeseeecneeseseneraeeeseererseenes Belt-drive
MOtOP suskeioccitdevasesssacecvasrepeees vie eeeresetene DC servo motor
Turntable Platter ...........:cceseseeeeeues aluminum alloy die-cast
SPECS ieee veer edces dendessecisbastedidancssnes nas 33-1/3 and 45 rpm
Wow and Flutter ..............0ee eee e ee Less than 0.05% (WRMS)
+ 0.065% WTD Peak (DIN)
Signal-to-Noise-Ratio .........cccseee More than 70 dB (DIN-B)
(with Pioneer cartridge model PC-291)
Tonearm
TY DO) iseiccvssannstusvssedessioisecessece Integrated straight pipe arm
TYPO costs ceiehscetnaladiedanceccccceasseatenpateceunvestepaoedetes IM type
Stylus sc.csssacteasecvivewseheiteecsssvestes 0.5 mil diamond (PN-291)
Output Voltage ........eccecceseseneeereeeneeeeeeeeeeeeeen ene 2.5mV
(1 kHz, 5cm/s LAT. Peak)
Tracking Force ........ccceeceeeeeeeee ee 1g to 1.5 g (proper 1.25 g)
Frequency RESponse ........:ccseeeeeeseeseseeeeeees 10 to 30,000 Hz
Recommended Load .......ccccceceseseeeeneeeneeanaeeeeeseenes 50 k&
WEIGH .......:cccesesccecscrscnsccsccecncnceecsea seer rsssaseneeeeenes 4g
Subfunctions
Auto lead-in, auto return, auto cut, repeat
Arm elevation, program search play, manual play,
Skip, auto disc size selector, record detection,
Auto speed selector,
Miscellaneous
Power Requirements .......ccsssssesssesssesenens AC 120 V, 60 Hz
Power Consumption .........ccssscesssssscereesceresseveceeeaeeserens 11W
Dimensions ............0se0eeeeees 420 (W) x 104 (H) x 350 (D) mm
16-1/2 (W) x 4-1/8 (H) x 13-3/4 (D) in.
Wight 223 cc. idesseedescdades avibanccnideddeseensaced 7.5 kg/16 lb 8 oz
Accessories
EP(Adapter’ ei eisescosteohe dneeecasacseutsgaacee diac Veadavbecewisindses 1
Remote control COrd .........ccccsceceeescuteceseeseecneeeneseenceaees 1
Remote control plate ...........cccscscececceeeceneeeeeeeseeneeertenaes 1
Operating INStructions ...........cccccsecececeneseeceeeeeeeenneseenee 1
NOTE:
Specifications and design subject to possible modification without
notice, due to improvements.

QUESTIONNAIRE
MODEL
One
Model
per
questionnaire
Dear Servicer,
Thank
you
for
your
cooperation
in
the
post-sale
service
of
Pioneer
products.
This
questionnaire
is
used
as
a
tool
to
improve
the
serviceability
of
our
products
and
service
manuals.
Please
evaluate
this
model
and
service
manual
by
answering
the
following
questions.
Your
ideas
may
be
realized
in
our
future
products.
Your
answers
will
be
appreciated.
Thank
you.
PIONEER
ELECTRONIC
CORP.
T.
Nakagawa,
Manager,
Service
Section,
International
Division
1.
SERVICING
EVALUATION
Circle
applicable
number:
Good
Poor
Fair
1
2 3
*4
0
*5
b.
Circuit
Checks:
1
2 3
*4
#5
1
2
3
*4
*5
d.
Adjustment
(s):
1
D)
3
*
4
*,
*
If
(4)
or
(5)
was
circled,
please
be
specific.

e. Your advice, opinion or ideas related to servicing this product.
2. SERVICE MANUAL EVALUATION
a. Circuit & Mechanism Description
b. Circuit Diagram
3. OTHER
Please describe other areas of servicing which you may find difficult.
Completed by :
Company Name :
Address :
City /State/Zip :
Please send this form filled to the distributor in your country.

2. FRONT PANEL FACILITIES
@ POWER switch/indicator
Press this switch to turn the power on and off.
[ON]
(depressed
position)
:
Power
is
switched
ON.
[STAND-BY]
(released
position)
:
Power
is
switched
OFF.
@) SPEED switch
Set
this
switch
in
accordance
with
the
speed
of
the
record
to
be played.
[AUTO]:
Automatically
sets
rotation
speed
in
accordance
with
the
size
of
the
record:
Rotates
at
33-1/3
rpm
with
30
cm
and
25
cm
records.
Rotates
at
45
rpm
with
17
cm
records.
(33): Rotates at 33-1/3 rpm
(45): Rotates at 45 rpm
@ SENSOR switch
Depending
on
the
type
of
record
being
played,
this
switch
may
be
used
to
adjust
the
sensitivity
at
the
time
of
program-
med play.
Normally
the
switch
should
be
left
in
[NOR]
position.
(NOR]: For normal records.
[HI]
:For
records
with
very
narrow
intervals
between
tracks.
{LO}:
For
records
with
wide
sound-groove
pitch.
@ PROGRAM switches (1 — 8)/ indicators
e
Press
these
switches
in
the
desired
sequence
from
[1]
through
[8]
when
programming
the
order
in
which
the
tracks
are
to
be
played.
The
tracks
are
programmed
in
the
order
in
which
the
switches
are
pressed,
and
auto
play
or
repeat
play
is
performed.
e
The
numbers
[1]
through
[8]
indicate
the
order
of
the
tracks
on
the
record
(for
instance,
the
[2]
switch
cor-
responds
to
the
second
track).
During
programmed
playback,
the
program
indicator
corresponding
to
the
track
presently
being
played
will
flash.
© CLEAR switch
This
switch
is
pressed
in
order
to
clear
the
program.
@® REPEAT switch/indicator
Press
this
switch
so
that
the
indicator
lights
for
repeat
play.
PL-V70,PL-L90
@ ARM ELEVATION switch
(ARM EV)/indicator
Use the switch for manual piay.
Use the switch to suspend record play temporarily.
Use
the
switch
when
changing
the
tracks
during
manual
play.
Indicator lights:
The tonearm rises (the stylus moves away from the
record).
Indicator flashes:
During right or left movement of the tonearm (or during
search for programmed play).
Indicator goes out:
The tonearm descends (the stylus is lowered onto the
record).
LOCATE/SKIP switches
(ARM LOCATE/PROGRAM SKIP)
Use these switches to start manual playback, or during
playback to change the track being played. When the
switches are pressed, the tonearm will move to the right or
left (the arm elevation indicator will flash).
[<, +]: Tonearm moves to left. During programmed play,
moves to the next programmed track. If pressed multiple
times, moves ahead the number of tracks corresponding to
the number of times the switch is pressed.
[>,
—
]:
Tonearm
moves
to
right.
During
programmed
play,
moves
back
to
the
beginning
of
the
track
presently
being
played.
If
pressed
multiple
times,
moves
back
the
number
of
tracks
corresponding
to
the
number
of
times
the
switch
is
pressed.
NOTE:
When pressing these switches two or more times during program-
med play to skip over two or more tracks, do not allow more than
about one second to elapse between each press of the switch.
(ia OS 2
@—E
c
a
‘a
=|
SascSEsEs
==
=r
@ PLAY/STOP switch
Press
this
switch
when
starting
auto
play
or
when
stop-
ping play.
EJECT button
Press when mounting or removing a record. When pressed,
the slide base comes out to the front.
@ Platter
@2) Platter mat
@) Platter shaft
Tonearm
48) Cartridge (PC-291)
EP adapter
This
is
used
when
playing
45
rpm
records
with
a
large
center
hole.
@ Cabinet
Slide base

PL-V70,PL-LSO
3. BLOCK DIAGRAM
Reset circuit
+82 (+5V)
System control IC
Qi
PD6037
Muting circuit
Remote control decode circuit
: 7)_ Xion iz)
DI7
REM OUT
pié
® Pull up (5V)
Key matrix
circuit
Phono motor interface circuit
+Bl (+12V)
PHONO
MOTOR
Ev t
(Drawing rod in)
Ev 2 (Holding rod in)
ARM <
appress (32)
ARM >
+Bi(l2v) +82 (5v)
+Bi(t2v)
Power supply circuit
Q3 M54547P
S| Sse
ere PT
(lav) Tonearm
=: drive motor
oe (11) (w) i“
reverse
|
(5)
river:
(14)
7
X
eae ZN
O D201
AC 120V | e—P = ig
60Hz
BAND SENSOR CIRCUIT
Bi (+!2v) (+5V) B2
;
= sie
Al al
feat |
i
ES
+1av
i ‘
LS 1
al |
A,
=
VR3
Q7(4/4)
H
Gay
2
eel
Nob
ves
ne
VR3:
Band
sensor
Record
_—»
ofaet
ADs
Center
suttace
Sut
sige
S18:
Sensor
sensitivity
‘
edge
of
LED:
NJLI{02EH
record
record
Ptr: PCX-059
Speed selector
+B2(5V)
Tonearm down sensor
Carriage board assembly
Guide bar
V sig
i Mechanism base board
assembly Q201
Tonearm address signal generator circuit
Tonearm drive
motor
Tonearm
down sensor
Tonearm
assembly
Shutter
| VR201
Tracking sensor
gain adjustment

PL-V70,PL-L9O
4. CIRCUIT DESCRIPTIONS
4.1
CIRCUIT
DESCRIPTIONS
as
Q3_M54547P
4.1.1.
Address
Sensor
Circuit
Sram
rin
4
r
1
The
address
sensor
is
located
on
the
mechanism
+H2v
1
base
unit.
It
detects
the
position
of
the
tonearm
and
sends
address
pulses
to
the
control
IC
as
the
tonearm
moves.
The
address
sensor
is
make
up
of
an
internal
Schmitt
trigger
circuit
photo
interrupter
and
a
slit
wheel
which
is
synchronized
with
the
carriage.
The
slit
wheel
spins
when
the
carriage
moves
and
intermittently
cuts
off
light
to
the
photo
interrupter
(Q301)
in
pulses
which
corre-
spond
to
the
carriage
movement.
These
pulses
are
counted
by
the
control
IC,
which
detects
the
distance
the
carriage
moves,
the
tonearm
lowering
Fig.
4-2
Tracking
sensor
circuit
position
and
the
end
of
the
record.
It
also
registers
band
addresses.
The
address
pulses
from
the
photo
interrupter
work
as
follows:
When
the
light
is
cut
off,
the
output
is
‘‘L,”
and
when
the
light
is
not
cut
off
the
output
is
“‘H.”
One
address
signal
pulse
is
ap-
proximately
equivalent
to
0.114
mm
of
tonearm
movement.
Tracking sensor
gain ADJ
Tonearm
drive motor
Sensor
Slit wheel
Fig. 4-1 Address Sensor Circuit
4.1.2
Tracking
Sensor
Circuit
This
circuit
detects
tracking
errors
by
means
of
a
shutter
which
is
synchronized
with
the
tonearm
and
a
photo
interrupter.
The
tracking
sensor
is
made
up
of
a
shutter
synchronized
with
the
tonearm
and
a
photo
interrupter
which
is
mounted
onto
the
carriage
base
board.
When
the
tonearm
lowers
and
begins
tracing
the
record
surface
the
tonearm
tracking
errors
increase
as
the
number
of
rpms
increases.
When
tracking
errors
increase,
the
shutter,
which
is
Liv
—»f——Tracking
center
synchronized
with
the
tonearm,
also
moves
and
the
light
cut-off
rate
of
the
photo
interrupter
changes.
Subsequently,
the
output
of
the
photo
interrupter
changes
and
is
sent
to
the
tonearm
drive
unit
in
the
form
of
tracking
error
signals.
_
Tracking error
3v f---->
Tracking error
Small Large
Fig. 4-3 Detection of tracking errors

L-V70,PL-L90
4.1.3 Band Sensor Circuit
The band sensor circuit detects the size of the
record
and
width
of
bands
by
means
of
a
band
sensor.
It
is
made
up
of
a
band
sensor,
an
amplifier,
a
differencial
amplifier,
a
zero
cross
comparator,
a
band
comparator,
a
30
cm
size
comparator,
an
AC
amplifier, and a search comparator.
The
band
sensor
itself
is
made
up
of
an
array
of
2
phototransistors
(PCX-059)
mounted
into
the
headshell
of
the
tonearm
and
an
infrared
LED
(NJL1102EH).
It
detects,
with
a
light
sensor,
the
different
rates
of
light
reflection
to
determine
the
difference
between
a sound
groove
and
a
plain
band.
The
output
of
the
band
sensor
is
amplified
by
each
of
the
amplifiers
and
applied
to
the
differential
amplifier
to
be
transformed
into
a
waveform
like
that
of
point
C
in
figure
4-5.
From
the
differential
amplifier
output,
the
zero
cross
comparator
detects
a
band
signal
(zero
cross
point),
and
the
band
comparator
detects
signals
whose
potential
is
less
than
Q6
(3/3)
pin
8
as
band
signals.
The output from the band sensor is also applied
to the AC amplifier and the 30 cm size comparator.
When in the search mode with the tonearm up,
the band sensor output is applied through the AC
amplifier (band pass filter configuration) and
the search comparator and transformed into the
waveform shown in F in figure 4-5. This signal is
applied to the control IC to register the plain bands
on the record.
The 30 cm size comparator, on receiving the
amplified output from the band sensor and detect-
ing reflection from the turntable at the 30-cm
lowering position, determines that the record is not
a 30-cm record, and sends the signal shown in G in
figure 4-5 to the control IC.
$18: Changes sensor sensitivity
Record center
Record outside edge
5V
(Output only when tracing)
(Output only when searching)
Turntable center Turntable outside edge
5
oe 3y
Reflection of turntable
at 30cm lowering position : |
Waveform at B
when there is
no record
Waveform at G when
there is no record or
a 17cm record
tv
Fig. 4-5 Waveform at Each Point
+B2(+5v)
ae
a»!
VR3 OP
Offset adjustment _ VN
«— Record ~~
Record Record
center outside ed ge
LED: NJLII02EH
P.Tr: PCX-059
Fig. 4-4 Band Sensor Circuit

4.1.4 Elevation and Tonearm Circuits
The
tonearm
drive
motor
and
EV
solenoid
are
controlled
by
commands
from
the
control
IC
(Q1),
which
also
controls
the
horizontal
and
vertical
movement
of
the
tonearm.
In
addition
to
this,
the
IC
controls
tonearm
tracking
with
the
tracking
sensor
and
tracking
error
signals.
e EV solenoid drive
The
EV
solenoid
drive
uses
a
large
current
at
first
to
draw
the
plunger
inside,
and
thereafter
uses
a
lower
current
for
holding
the
plunger
in.
The
signal
to
draw
the
plunger
inside
comes
from
the
control
IC
(Q1),
passes
through
the
Q2
transistor
array,
and
enters
Q3
pin
7.
This
signal
turns
on
the
Q3
Darlington
transistor,
and
ap-
proximately
170mA
of
current
runs
into
the
collector,
turning
on
the
EV
solenoid
which
draws
the
plunger
inside.
Because
of
this,
the
tonearm
will
drop
slightly.
This
“draw”
signal
from
the
control
IC
lasts
about
1
second.
Next,
the
hold
signal,
which
was
output
at
the
same
time
as
the
draw
signal,
passes
through
the
Q2
transistor
array,
enters
Q3
pin
8
and
turns
on
the
Darlington
transistor.
When
the
draw
signal
ends,
a
current
of
approximately
70mA
drawn
from
pin
9
holds
the
plunger
inside,
which
keeps
the
tonearm
elevation
down
until
the
hold
signal
ends.
Tracking
error
tlev
signal
1V-wfe— Tracking center
/
0/Smatl-+Large
Q3: M54547P
PL-V70,PL-LS0.
@ Tonearm drive
The tonearm drive is controlled by input to Q3
pin 4, pin 5 and pin 15. Their truth values are
shown in Fig. 4-6.
@ Lead-in (iocate-in) <<
Q3 receives locate-in signals from the control IC
(Q1), and with an output of approximately 0V
from Q3 pin 14 (O1) and approximately 11V
from pin 11 (O02), the tonearm motor begins
turning in the lead-in direction.
@ Lead-in (locate-out) >
Q3 receives locate-out signals from the control
IC (Q1), and with an output of approximately 11V
from pin 14 and approximately OV from pin
11, the tonearm motor begins turning in the
lead-out direction.
@ Stop
Q3 receives stop signals from the control IC
(Q1), and with an output of approximately 0V
from both pin 14 and pin 11, stops the tonearm
motor.
@ Tracking
Q3 receives tracking signals from the control IC
(Q1), and between pin 14 and pin 11, outputs an
amplified tracking error signal (amplified by an
internal OP amplifier) and begins turning the
tonearm drive motor in such a way as to correct
the error.
—$— : Pull up resistor
@1®
Tonearm
drive motor
EV SW ON
Vv
ae! a
our
eae
Output
TREE Tonearm
@ operation
Lead-in <
Lead-out >
Pepe t fo
Ll L H L.
H tl L Ll
pepe Ta Pe Te [tome
1 ‘
{Tonearm: Tong rm
‘down jtup
Stop
Fig. 4-6 Elevation and Tonearm Drive Circuit and 1/O
Truth Value Chart

DL-V70,PL-L9O
4.1.5 Key Matrix Circuit
The key matrix circuit reads the digit output
(pins 22 to 25) of the control IC (Q1) from the
Key IN terminal (pins 26 to 29) and distinguishes
different key input signals with the control IC. In
addition to carrying out key input operations, it
lights LEDs with output from pins 17 to 19. Fig.
4-8 shows the output waves produced by switch
matrix input in the following order: REPM SW,
Program SW 7, and EV SW.
S13 (>) ] Si4(S/s)
oe 2 77
al
SO(CLR) J SIO(REP) 2 SIL(<) JSI2(EV)
yo yeh yA a
O18
te
$5 (5) $6 (6) $7(7) $8(8)
yt xt y 3
O17 p p |
Si (1) $2(2) ) $3(3) $4 (4)
ee ae <4 xe
+61
Qi8
@)
Kb) DIO My 011
his #Qis,| ¢Bro)
(yy
&) | 06 go? 08 D9
as 2H) ABDa) FB (3) 4H)
«)
Fig. 4-7 Key Matrix Circuit
Program
Control
SWs
all
OFF
[REP]
sw
on
C7]
sw
on
fev]
sw
on
06037 Po - _-0%% —Po- SW matrix
ea
= ne: sw
= 2 6 apes
11.2 mSEC s 4 5] CUR >|
2.8 mSEC
23 >+—+4
a
wn PER, [YP
17
a sls pyr | LED
19 t 2 3 |
Display LEDs all OFF LEO ON (REP), (].e0 on {reF],(7] [UP}ieo on LED matrix
REP @~ —_—_— ar OY ——qc34“r REP @~ a
or =
@- ——
vw Q@- ———
Fig. 4-8 Output Waveforms Produced by Key input
10