Akai AP-207 User manual

AP-307
AKAI
DIRECT
DRIVE
FULLY
AUTOMATIC
TURNTABLE
AND
QUARTZ
LOCK
DIRECT
DRIVE
FULLY
AUTOMATIC
TURNTABLE
woo.
AP-207
AP-307
ALSO
APPLICABLE
TO
BLACK
MODEL
SECTION
1
SERVICE
MANUAL
........---2
eee
eters
3
SECTION
2
PARTS
LIST
.........--
22:
ee
eee
eee
29
SECTION
3.
SCHEMATIC
DIAGRAM
......-.------++->
-...
48

Il.
ii.
VI.
VII.
VOI.
SECTION 1
SERVICE MANUAL
TABLE OF CONTENTS
TECHNICAL DATA .. 0.22... eee putt & eegh ses 4
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2: MODEL CAR BOF casera Jieeela wlaee woe eed HONG Cpe AT alate eletes 4
DISMANTLING OF UNIT... 1.0 ee ee ene 5
CONTROES » Gees acceso has ebm Ses a Sere a Gy etes BME sg OH MLR So Be Shae 6
1. MODEL: AP-207 i356 /c bi ate aid ae es eh Eevee at oe ed anaes 6
2 MODEEVAP-3O7 0 3 bles eed oe BASE a Meee emp ae ese Lee Re 7
PRINCIPAL PARTS LOCATION .......... hs aa Lhd ithe: yang ca Mesiaie ae 8
Le (MODEG.AP-207) copa ed ee Pete eek eae Bae SA s Bes 8
22 MODEL. APIS O07: 22s sc¢8 tla hee ihe og HOS oP Vee oa eee eres 8
BLOCK DIAGRAM .. 1... 0.6 en tee eee eens 9
Le: MODDED AP2207 iieic gale 2 age ere oh US oe ees Ba ee ee eee 9°
2. MODEEAP-307) «ence oe cog CMa Pe Ve bbe see ee ee 9
CIRCUIT OPERATION . 00.1. eee eee eens 10
Pe GENERATS 250.628 oi ngechee to aie nethnd. salar eos nee aap oe eke Mae tea aed 10
2. SERVO CIRCUIT 4 a2.ac naa sping wee ane tides Saw palatine 10
3. STROBE LIGHT CIRCUIT .. 0.0... ce ee eee 11
MECHANICAL ADJUSTMENT ...... 0... cee cee eee eee 12
1. STYLUS PRESSURE ADJUSTMENT ....... 2.0.00 cece eee eeee 12
2. OVERHANG ADJUSTMENT .. 1.0... ec eee 13
3. SLEEVE POSITION ADJUSTMENT .. 1.2.0... 00... eee eee eee eee 14
4, ARM LIFTER HEIGHT ADJUSTMENT .........0.. 00.00 -eeeee 14
5, AUTOMATIC ARM CONTROL ADJUSTMENT ...........-..--5.- 15
ELECTRICAL ADJUSTMENT .... 1.0... cee ee ee eens Le. 16
1, DIRECT DRIVE P.C BOARD ADJUSTMENT ...............4-. . 16
2. PLL P.C BOARD ADJUSTMENT ........ Piossatlel eh cate ya lon de sec ah? oeaatea ea hha _ 17
CLASSIFICATION OF VARIOUS P.C BOARDS ...........00 2 eee 19
1, P.C BOARD TITLE AND IDENTIFICATION NUMBER ............ 19
2. COMPOSITION OF VARIOUS P.C BOARDS ..............0-.0055 . 20

I TECHNICAL DATA
1. MODEL AP-207
TURNTABLE
314
mm
aluminium
alloy
die-cast
DRIVE
SYSTEM
Direct
Drive,
Fully
Automatic
MOTOR
Bb
DC
Servo
Motor,
Geared
Motor
for
Tone
Arm
Drive
SPEED & PITCH CONTROL
33-1/3 and 45 rpm +2.5%
SPEED ACCURACY
1,000 Hz +0.15%
WOW AND FLUTTER
0.035% (DIN), 0.025% (JIS)
RUMBLE
Better
than
49
dB
(DIN
A),
70
dB
(DIN
B)
TONE
ARM
Static
balanced
type
with
Anti-skating
Adjuster
ARM
LENGTH
220
mm
STYLUS PRESSURE ADJUSTMENT RANGE | 0 to 3 grams
APPLICABLE
CARTRIDGE
WEIGHT
4
to
12
grams
ARM LIFTER Oil-damped
OVERHANG | 15 mm
OFFSET ANGLE 22°30'
HORIZONTAL TRACKING ERROR ANGLE +2°
SHELL WEIGHT
i 7.8 grams
POWER REQUIREMENTS
120V, 60 Hz for U.S.A. and Canada
220V, 50 Hz for European countries
240V, 50 Hz for U.K. and Australia
110 to 120V, 220 to 240V switchable 50/60 Hz for other countries
DIMENSIONS
440(W)
x
158(H)
x
350(D)
mm
WEIGHT
T
81kg
*
For
improvement
purposes,
specifications
and
design
are
subject
to
change
without
notice.
2. MODEL AP-307
TURNTABLE
314
mm
aluminium
alloy
die-cast
DRIVE
SYSTEM
Quartz
Lock
Direct
Drive,
Fully
Automatic
MOTOR
DC
Servo
Motor,
Geared
Motor
for
Tone
Arm
drive
SPEED & PITCH CONTROL
33-1/3 and 45 rpm 42.5%
SPEED ACCURACY
1,000 Hz +0.08%
WOW AND FLUTTER
0.035% (DIN), 0.025% (JIS)
RUMBLE
Better
than
49
dB
(DIN
A),
70
dB
(DIN
B)
MOMENT
OF
INERTIA
230
kg.cm?
TONE
ARM
Static
balanced
type
with
Anti-skating
Adjuster
ARM
LENGTH
220
mm
STYLUS
PRESSURE
ADJUSTMENT
RANGE
0
to
3
grams
APPLICABLE
CARTRIDGE
WEIGHT
4
to
12
grams
ARM
LIFTER
Oil-damped
OVERHANG 15 mm
OFFSET ANGLE 22°30'
HORIZONTAL TRACKING ERROR ANGLE +2°
SHELL WEIGHT 7.8 grams
POWER REQUIREMENTS
120V, 60 Hz for U.S.A. and Canada
220V, 50 Hz for European countries
240V, 50 Hz for U.K. and Australia
110 to 120V, 220 to 240V switchable 50/60 Hz for other countries.
DIMENSIONS
440(W) x 158(H) x 350(D) mm
WEIGHT
8.6 kg
*
For
improvement
purposes,
specifications
and
design
are
subject
to
change
without
notice.

i. DISMANTLING OF UNIT
-
3
TURNTABLE
In case of trouble, etc. necessitating dismantling, please
dismantle in the order shown in the photographs.
Reassemble in reverse order.
___|
—
BOTTOM COVER
\
\
\
DUST COVER ~
hn qg f
SCREWS
CARTRIDGE
TABLE SHEET
NOTE: Photos of dismantling are those of AP-307, but the order applies to AP-207 also.

iil, CONTROLS
1. MODEL AP-207
ae N= 0
0.8 MN: DP O'e WUN >
MEDEA DW OOOOU® ©
HINGE
TURNTABLE PLATTER
SPINDLE
TONE ARM LIFTER
POSITION FOR 45 rpm ADAPTOR
STYLUS PRESSURE SCALE RING
HINGE
MAIN WEIGHT
ANTI-SKATING ADJUSTOR
TONE ARM LIFTER LEVER ¥ UP ¥ DOWN
. DISC SIZE SELECTOR/MANUAL
. START/CUT REPEAT LEVER
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24,
Fig. 1
LOCKING NUT
CARTRIDGE SHELL FINGER LEVER
CARTRIDGE SHELL
TONE ARM
TONE ARM REST
RUBBER MAT
OVERHANG ADJUSTMENT SCALE
STROBE MARKINGS
33 rpm PITCH CONTROL
45 rpm PITCH CONTROL
33/45 rpm SPEED SELECTOR 33 -m 45 -=
BUILT-IN STROBE LIGHT

2. MODEL AP-307
eee N > Oo
0 OR OL i Ne
HINGE
TURNTABLE PLATTER
SPINDLE
TONE ARM LIFTER
POSITION FOR 45 rpm ADAPTOR
STYLUS PRESSURE SCALE RING
HINGE
MAIN WEIGHT
ANTI-SKATING ADJUSTER
TONE ARM LIFTER LEVER ¥ UP © DOWN
. DISC SIZE SELECTOR/MANUAL
. START/CUT REPEAT LEVER
13,
14,
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
Fig. 2
LOCKING NUT
CARTRIDGE SHELL FINGER LEVER
CARTRIDGE SHELL
TONE ARM REST
TONE ARM
RUBBER MAT
OVERHANG ADJUSTMENT SCALE
STROBE MARKINGS
PITCH CONTROL SWITCH
QUARTZ LOCK SWITCH
33/45 rpm SPEED SELECTOR SWITCH
BUILT-IN STROBE LIGHT

IV. PRINCIPAL PARTS LOCATION
1. MODEL AP-207
POWER SUPPLY PRC BOARD
(AP - 2641)
t
POWER TRANS
PHONO RC BOARD
(AP-0319)
(T901)
D.D RC BOARD
(AP-2642)
{9
fr
aN
a
MOTOR(DDM~-33D)
Mh saPan sh
ay
save
:
bes
AUTO MECHA BLK
MICRO SWITCH
sw902,SW903
TIMING MOTOR
MICRO SWITCH
NEON LAMP PC BOARD
(AP- 2643)
Sw90l, SW904
START CAM
Fig.3 Bottom View
2. MODEL AP-307
POWER SUPPLY RC BOARD
(AP- 2641) pa
POWER TRANS
PHONO P.C BOARD
(AP-
0319)
(T901)
D.D RC BOARD
(AP-2642 )
AUTO MECHA BLK
MOTOR (DDM-33D)
MICRO SWITCH
Sw902 ,SW903
TIMING MOTOR
MICRO SWITCH
SW90!,
SW904
NEON
LAMP
RC
BOARD
(AP-2643)
PLL RC BOARD
(AP-3601)
START CAM
Fig.4 Bottom View

Vv.
BLOCK
DIAGRAM
a
SS
ee
1. MODEL AP-207
WAVE MULTI
corre! PLIER
-CTION) (2f)
33-1/3 f =20Hz
45 f=27Hz
+B
45 ——— 33-1/3
SPEED SELECTOR
Fig. 5
2. MODEL AP-307
STROBE CIRCUIT
4.42368MHz
ie
COUNT
DOWN{—>
COUNT
DOWN
COMPARATON
SPEED QUATZ Sis
& &
ISeLector
tock
|
4 § o
+B
i i
SCHMITT
tS
2S
33-1/3 = 45 ON—=—— OFF =
TRIGGER
B23
=
R90
LPF
PITCH CONTROL
Sad Lea
ELEME
33-1/3 f220H2
45. t227Hz
|
amp
|
CLAMP
BAFFER
N
HOLE
ee
‘
ELEMENT
\
\
\
Nee
oe
oe
oe
ii
ea
ia.
et
tm
le
a
rp
oe
as
leh
fi
ee
ee
ee
ee
es
ee
ee
oe
ee
Fig. 6

VI. CIRCUIT OPERATION
1.
NAND
EXCLUSIVE OR GATE
(=ANTI~COINCIDENCE)
De o> BD +e
GENERAL
The AP-207 has a D.D (Direct Drive) P.C Board
(AP-2642) that contains a FG (Frequency Generator)
the signal output of which controls the motor.
The AP-307 has a PLL (Phase-Locked Loop) P.C
Board (AP-3601) in addition to the electrical circuit
in the AP-207.
The PLL Circuit in the AP-307 consists of a Quartz
Lock Circuit and a Stroboscope Circuit. The strobe-
scope circuit flashes the neon tube NE901 in
synchronism with the frequency to which the crystal
oscillator frequency is accurately counted down,
while the neon tube NE901 in the AP-207 is activated
by the line power to flash the stroboscope patterns
on the turntable.
. SERVO CIRCUIT
1) Operation when the Quartz Lock Switch SW903 is
OFF
(Refer to the D.D. Circuit schematic diagram of
the AP-307.)
The motor incorporates a FG coil that produces
FG signal as the motor rotates. The FG signal
frequency is 20 Hz for 33-1/3 rpm and 27 Hz for
45 rpm. The FG signal is magnified through IC1
(4 to 8). The magnified FG signal is clamped to
positive side by R40 and VR1, and enters IC2 @.
In IC2, the signal is waveform-shaped and fre-
quency-doubled. The doubled signal is fed to IC3
@), as an input to Mono Multi.
The Mono Multi provides a characteristic that its
stable state is inverted by an external trigger into
the unstable state, where it remains for a predeter-
mined time before returning to the original stable
state. The pulse output of Mono Multi IC3 @ is
smoothed by C7 to DC which is led to IC1 @ as
the voltage to be compared. When the Quartz
Lock Switch SW903 is off, a reference voltage is
applied to IC1 @.
The voltage at IC1 @ is compared with the
reference voltage at IC1 @), and the output
appears at. IC1 @. The output at IC1 @ is passed
through the phase correction circuit, consisting of
Fig. 7
C9 thrrough C11 and R18 through R20, to TRI.
TRI. TR1 makes current flow through the Hall
Elements H1 and H2, which are installed in posi-
tion under the rotor magnet of the motor. The
voltage developed across each Hall element is in
proportion to the current flowing through the Hall
Elements and the strength of the magnetic field of
the rotor magnet.
The voltages output of the two Hall elements are
supplied to the motor drive amplifier, consisting of
IC4 (4 to 8), TR2 and TR3 and IC4 (1 to 3), TR4,
and TRS, to control motor speed.
If the motor speed is made late by some cause, the
FG signal frequency becomes lower. The width of
the pulse output of the IC3 Mono Multi becomes
wider. This increases the comparison voltage at
IC1 @, which in turn raises the voltage output of
IC1 @. The result is an increase of the current
flowing through TRI and the Hall elements Hi
and H2. The current increase the motor drive
amplifier so as to make the motor speed fast.
2) Operation when the Quartz Lock Switch SW903 is
ON
(Refer to the PLL Circuit schematic diagram of
the AP-307)
The 4.42368 MHz signal generated by the crystal
oscillator is delivered through TP-1 to IC2 @). The
Flip-Flop in IC2 halves the oscillation frequency
of 4.42368 MHz. The frequency-halved signal is
delivered as a clock pulse to IC3 @, which counts
it down to 1/27 (81.920 Hz) for 33-1/3 rpm or
1/20 (110.592 Hz) for 45 rpm according as set by
the Speed Selector Switch SW902. The count-
down signal, which appears at IC3 QQ, is further
counted down to 20 Hz for 33-1/3 rpm or 27 Hz
for 45 rpm at IC4 @. This output signal of IC4
@® enters the comparison circuit in ICS @, asa
set pulse.
On the other hand, the FG signal fed through the
D.D circuit to the PLL circuit is waveform-shaped
by the Schmitt trigger in IC1 (10 to 13), and is fed
through IC1 @, and R3 to ICS as the reset

a
pulse.
The
reset
pulse
of
20
Hz
for
33-1/3
rpm
or
27
Hz
for
45
rpm
shaped
from
the
FG
signal
is
compared
with
the
above-mentioned
set
pulse
entering
ICS
@,
and
the
output
appears
at
ICS
@.
The
output
pulse
is
smoothed
by
the
low-pass
filter,
consisting
of
C9,
C10
and
R5
through
R7,
and
enters
IC5
@),
then
the
inverted
output
is
fed
from
IC5
@.
The
output
of
ICS
@
fed
through
R8
and
SW903
to
IC1
@),
in
the
D.D
circuit
as
the
reference
voltage.
In
short,
when
the
Quartz
Lock
Switch
SW903
is
off,
the
reference
voltage
is
made
of
the
+B
voltage,
while
when
it
is
on,
the
pulse
made
of
the
FG
signal
is
compared
with
the
pulse
generated
by
the
crystal
oscillator
to
produce
the
reference
voltage.
The
succeeding
operation
is
similar
to
the
one
when
the
Quartz
Lock
Switch
is
off.
3. STROBE LIGHT CIRCUIT
(Refer
to
the
PLL
Circuit
schematic
diagram
of
the
AP-307)
The
4.42368
MHz
signal
generated
by
the
crystal
oscillator
is
delivered
through
TP-1
to
IC2
@).
The
Flip-Flop
in
IC2
halves
the
oscillation
frequency
to
2.21184
MHz.
The
halved
signal
is
fed
from
IC2
@,
to
IC3
@®.
IC3
counts
the
frequency
down
to
1/27
for 33-1/3 rpm or 1/20 for 45 rpm.
The
count-down
signal
is
fed
from
IC3
10,
to
IC4
®@.
IC4
further
counts
the
signal
down
to
160
Hz
at
IC4
@
,
320
Hz
at
IC4
@
and
80
Hz
at
IC4
@
for
33-1/3
rpm
or
to
216
Hz,
432
Hz
and
108
Hz
for
45
rpm,
respectively.
These
output
signals
are
input
to
the
NOR
circuit
of
IC6
(1
to
5).
The
NOR
circuit
outputs
from
IC6
@,
80
Hz
signal
for
33-1/3
rpm
or
108
Hz
signal
for
45
rpm.
The
signal
is
fed
through
R10
to
TRI
to
turn
on
and
off,
which
flashes
the
neon
lamp
NE901.
Reference:
Logic
Symbols
and
Their
Truth
Table

Vil MECHANICAL ADJUSTMENT
(a) (b)
Fig. 8
1. STYLUS PRESSURE ADJUSTMENT
1) Plug the power cord into a wall outlet of rated
voltage.
2) Unlock tone arm.
3) Bring the tone arm over to the turntable to start
the motor. Pull the Start/Cut lever toward you and
release immediately.
4) Wait until the tone arm lift is completely lowered.
5) Keep the tone arm between the turntable and arm
rest without touching either.
6) Rotate the main weight backward until the tone
arm is in perfect horizontal balance. (Zero balance
is attained.)
CAUTION 1: Be sure that the Anti-skating Ad-
juster is set to zero.
2: Be careful not to damage the stylus.
7) Without moving the main weight, turn the stylus
pressure scale ring only to match the “O” mark
with the marker on the weight shaft (see Fig. 8).
8) Turn the main weight counterclockwise (as viewed
from the front) with the stylus pressure scale ring
until the marker on the weight shaft corresponds
to the desired stylus pressure on the scale.
NOTES 1: The AP-207 and AP-307 Black and
Silver Panel Models do not come
equipped with cartridge.
2: If there is outside interference, it is
needed that the stylus pressure should
be increased for stable playback. The
range of adjustable stylus pressure is
from 0 to 3 grams.
9) Set the Anti-skating Adjuster to correspond to the
stylus pressure. (Fine adjust if necessary.)
12

@ SPINOLE H
@ GROOVE Sy Le
@ TABLE SHEET 15 mm
. OVERHANG ADJUSTMENT(Refer to Fig. 9)
The distance between the turntable spindle and the
stylus when the tone arm is at the center of the turn
table is called overhang. Different cartridges require
different overhang adjustments. For your conve-
nience, the rubber turntable mat had indicator groove
at the center for easy overhang adjustment. Bring the
tone arm to the center of the turntable. Adjust the
cartridge position in the cartridge shell so that the
stylus position is even with the outside groove ring.
The cartridge position is adjustable by resetting the
screws on the cartridge shell.
— -—O
Fig. 9
13

CABINET
Fig. 10
. SLEEVE POSITION ADJUSTMENT
(Refer to Fig. 10)
The sleeve position adjusts anti-skating feature.
1) Put the tone arm in the “stop” state, or on the
arm rest.
2) Set the sleeve, located between the PU Plate and
the chassis, to approximately 45° position as
shown in Fig. 10.
(a)
An
Fig. 11
ABOUT 8mm
Fig. 12
4, ARM LIFTER HEIGHT ADJUSTMENT
(Refer to Fig. 11 and Fig. 12)
1) Loosen the set screw (a).
2) Adjust the tone arm lifter stylus is around 8 mm
above the disk surface when the tone arm is put on
the tone arm lifter.
3) Make certain that silicon oil remains on the lifter
plate. If not, apply it to assure smooth tone arm
movement.

STYLUS PRESSURE
© [SCALE RING
ANTI-SKATING ADJUSTER
Fig.
13
Fig.
14
ADJUST
SCREW
Fig.
15
5.
AUTOMATIC
ARM
CONTROL
2)
Stylus
Lead-out
Adjustment
ADJUSTMENT
(Refer
to
Figs.
9,
10
and
11)
a)
Hold
the
tone
arm
put
on
the
arm
rest.
b)
For
a
30
or
25
cm
disk,
adjust
the
adjust
screw
seen
through
the
adjust
hole
(see
Fig.
13)
until
the
stylus
is
lifted
up
at
an
appropriate
point
in
the
lead-out
groove.
For
a
17cm
disk,
remove
the
bottom
cabinet,
and
similarly
adjust
the
adjust
screw
shown
in
Fig.
15..
NOTE:
The
range
B
of
lead-out
groove
on
which
the
stylus
is
to
be
lifted
up
is
(refer
to
1) Stylus Lead-in Adjustment
a)
Bring
the
tone
arm
toward
the
center
of
the
turntable
until
the
adjust
screw
is
seen
through
the
adjust
hole
located
_as
in
Fig.
13.
b)
Adjust
the
adjust
screw
until
the
stylus
is
dropped
down
onto
an
appropriate
point
in
the
lead-in
groove
of
a
disk.
NOTE:
The
range
A
of
lead-in
groove
on
which
:
;
Fig.
14):
the
stylus
is
to
be
dropped
down
is
(refer
169
to
115
iam
diarteter
for
30
an
4
25
to
Fig.
14):
;
cm
disks.
+
293
to
298
mm
diameter
for
30
cm
disk.
242
to
247
mm
diameter
for
25
cm
disk.
168
to
173
mm
diameter
for
17
cm
disk.
»
98
to
106mm
diameter
for
17
cm
disk.
CAUTION:
Do
not
use
any
disk
or
phono
sheet
other
than
the
one
complying
with
the
JIS
standard
or
equivalent
disk
for
stylus
lead-in
and
lead-out
adjust-
ments.
ee

Vill. ELECTRICAL ADJUSTMENT
§
VRS VRE
Gone aoe 300KB
ore ‘Ser VOLTAGE
> 2)
VR2,VR3 SPEED
= 20 2i
VR2
10OKB _100KB aed
(a) IDEAL
(All peaks are at the same level)
1. DIRECT DRIVE P.C BOARD ADJUSTMENT
1) Off-set Voltage Adjustment (VR4, VRS)
a) Disconnect the motor, or make open pins 4
through 11 and 14 and 15, leaving the other
pins connected.
b) For VR4, connect a digital DC voltmeter to
pins 6 and 8 (ground).
c) Shortcircuit pins 9 and 10.
d) Move the tone arm to turn the power on.
e) Adjust VR4 until the output at pin 6 is OV +10
mV for the AP-2-7 and 80+10 mV for the
AP-307.
f) For VRS, in turn, connect the digital DC volt-
meter to pins 7 and 8 (ground).
g) Shortcircuit pins 4 and 5.
h) Adjust VR5 until the output at pin 7 is OV +10
mV for the AP-207 and 80 +10 mV for the AP-
AP-307.
TORQUE
DIFFERENCE
O
Fig. 16
(b) BAD
(Peak levels are not equal)
Fig. 17
2) Duty Ratio Adjustment to 1:1 (VR1)
a) Connect an oscilloscope to TP-1.
b) Set the SPEED selector to the “33-1/3” posi-
tion.
For the AP-307, release the QUARTZ LOCK
button to the OFF position.
c) Move the tone arm to rotate the motor.
d) Adjust VR1 until the oscilloscope shows such
a waveform as illustrated below.

>
Fig. 18
ISP
5
6
7
98
0
ee |
i W
O- svrt
50K
es
8}
TP-I
[o)
OF
3) Torque Difference Adjustment (VR6)
a) Connect a dual-channel AC voltmeter to pins
6, 7 and 8 (common ground).
b) Set the SPEED selector to the “33-1/3’’ posi-
tion. For the AP-307, release the QUARTZ
LOCK button to the OFF position.
c) Move the tone arm to rotate the motor.
d) Adjust VR6 until the outputs at pins 6 and 7
are of the same level.
NOTE: As the output frequency is as low as a
few Hz, the voltmeter needles will vibrate
minutely. In the state of correct adjust-
ment, the two needles will seem inter-
wining as shown below.
CAUTION: In this adjustment, the voltages are
determined by the motor rpm so
they should only be matched in as
much as that vary.
4) Speed Adjustment (VR2, VR3)
a) Set the SPEED selector to the “33-1/3’’ posi-
tion. For the -AP-307, release the QUARTZ
LOCK button to the OFF position.
b) Set the PITCH control to the center.
c) Move the tone arm to rotate the motor.
d) For the AP-207, adjust VR3 until the strobo-
scope pattern on the first line for 50 Hz power
or the second line for 60Hz power is seen
standing still. For the AP-307, also adjust VR3
until the single stroboscope pattern is seen
standing still.
O VC} osc FREQUENCY
p QUARTZ - LOCKED PHASE ANGLE
ROW |
ROW 2
Row 3
ROW 4
Fig. 19
e)
In
turn,
reset
the
SPEED
selector
to
the
“45”
position. ©
f) For the AP-207, similarly adjust VR2 until the
stroboscope pattern on the third line for 50 Hz
power or the fourth line for 60 Hz power is
seen standing still.
NOTE: It is important that the pattern should
not rotate in the reverse direction of the
motor, or rightward as in the above line
drawing.
2. PLL P.C BOARD ADJUSTMENT
(AP-307 Only)
1) Oscillation Frequency Adjustment (VC1)
a) Connect a frequency counter to TP-1 and pin
5 (ground).
b) Set the SPEED selector to the “33- Bs, posi-
tion.
c) Move the tone arm to turn power on.
d)
Adjust
VC1
until
the
frequency
counter
reads
4,423,680 +10 Hz.
CAUTION: For turning VC1, use a RF adjusting
screwdriver.
reer
ge
i
ES
TT
17

18
22 +2msec
AROUND 7.5V -
2V to 4V
Ov
Fig. 21
TLSV =s-S=
ete ipactet halal
PULSE PULSE
2V to 4V ve tee
OV rns
(a) (b)
Fig. 22
2) Quartz-Locked Phase Angle Adjustment (VR1)
a) Connect an oscilloscope to TP-2 and pin. 5
(ground).
b) Release the SPEED selector to the ‘33-1/3”
position.
c) Depress the QUARTZ LOCK button in (ON).
d) Move the tone arm to turn power on.
e) Adjust VR1 until the width of the upward
pulse above 2 to 4V is 22 +2 msec when the
stroboscope pattern is seen standing still, as
Fig. 20.
CAUTION: The upward pulse around +7.5V
shown above may change to down-
ward pulse (OV) below 2 to 4V with
VRI turned as Fig. 22(a). Be careful
not to measure the width of the
downward pulse. It can be checked
in a simple way as the upward pulse
will change to a downward pulse
when some pressure is applied to the
platter by hand.
This adjustment must be made with
an oscilloscope of 1M ohm input
impedance using 10:1 probe and
must be conducted in the DC mode.
When the input impedance is other
than 1 M ohm and the waveforms are
observed in the AC mode, pulse
width changes and correct adjust-
ment cannot be made.

IX.
CLASSIFICATION
OF
VARIOUS
P.C
BOARDS
1.
P.C
BOARD
TITLE
AND
IDENTIFICATION
NUMBER
P.C
Board
Title
P.C
Board
Number
Utilizing
Model
-
Power
Supply
P.C
Board
AP-2641
AP-207,
AP-307
D.D
P.C
Board
AP-2642
AP-207,
AP-307
Neon
Lamp
P.C
Board
AP-2643
AP-207,
AP-307
PLL
P.C
Board
AP-3601
AP-307
19

2. COMPOSITION OF VARIOUS P.C BOARDS
1) D.D. P.-C BOARD AP-2642
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VRSOl 20KB
VR902 20KB
VR901,902
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20