Pioneer PL-7 User manual

Service
PMALEVINIED
REPAIR
&
ADJUSTMENTS
ORDER
NO.
ART-701-0
STEREO TURNTABLE
L=— 7
PL-720
MODEL PL-7 COMES IN SEVEN VERSIONS DISTINGUISHED AS FOLLOWS:
Voltage Remarks
120V only U.S.A. model (Without cartridge)
120V only Canada model (Without cartridge)
220V — 240V Europe model
220V — 240V United Kingdom model
220V — 240V Oceania model
110V—120V/220V—240V (Switchable) General export model
110V-120V/220V—240V (Switchable) U.S. military model
MODEL
PL-720(which
is
minor
change
in
design
from
PL-7)
COME
IN
FIVE
VERSIONS
DISTINGUISHED
AS FOLLOWS:
Voltage Remarks
220V — 240V Europe model
220V — 240V United kingdom model
220V — 240V Oceania model (Without dust cover)
110V—1 20V/220V—240V (Switchable) General export model (Without dust cover)
110V—1 20V/220V—240V (Switchable) U.S. military model (Without dust cover)
a This is the service manual for model PL-7/KUT. For servicing of the other types,
please refer to the additional service manual.
= Ce manuel d’instruction se refére au mode de réglage, en francais.
= Este manual de servicio trata del método de ajuste escrito en espafiol.
PIONEER ELECTRONIC CORPORATION
FU ©APR. 1981 Printed in Japan

= For the circuit and mechanism descriptions, please refer to the supplement of model PL-7 service manual
(ART-768).
CONTENTS
1. SPECIFICATIONS .............. 00000 2
2. FRONT PANEL FACILITIES. ............. 3
3. DISASSEMBLY .. 1... ee ee ee eee 4
4, TROUBLESHOOTING..............5008- 7
5, PRECAUTIONS FOR REASSEMBLY........ 15
6. ELECTRICAL PARTS LIST.............. 18
7, BLOCK DIAGRAM...............-400- 20
1. SPECIFICATIONS
Motor and Turntable
DriVE SYSTEM <5 eles: na see Dee ee ka ee a oS Direct-drive
MOTOR 22 oie! edit ancivtenas st tl end tern aca, Serb Deteda, Quartz PLL Hall motor
Turntable Platter ......... 310mm diam. aluminum alloy die-cast
SPOOUS? os ei isende s seect scat a8 a ered teestcayh RE aye a ele a 33-1/3 and 45rpm
Wow and Flutter ..............2.05. Less than 0.025% (WRMS)
Signal-to-Noise Ratio................ More than 78dB (DIN-B)
(with Pioneer cartridge model PC-3MC)
Tonearm
TYPO sx esiyt Ma vedle hie laee Static-balance type, Straight pipe arm
Effective Arm Length. .......... 0.002000 eee ee ee eee 221mm
OVErHANG Seidink onto aces Sa ee she ahha ehotaw ele 15.5mm
Usable Cartridge Weight................ 3g (min.) to 8g (max.)
Subfunctions
Full auto mechanism, Anti-skating force control, Stylus pressure
direct-readout counterweight, Cueing device, Strobe light, Free stop
hinges
8. P.C. BOARDS CONNECTION DIAGRAM .... 21
9. SCHEMATIC DIAGRAM ................ 23
10. EXPLODED VIEWS ................40. 25
11. ADJUSTMENTS. ......... 0.00000 eee 30
REGIAGE. oF cco hes eina bdo 32
AJUS TE: ccs he eee te is oa ee walter ae 3 34
Miscellaneous
Power Requirements... ......2.0 2 2 peewee AC120V, 60Hz
Power Consumption .............000 000000 be ee Sw
Dimensions .............. 420(W) X 108(H) xX 367(D)mm
16-1/2(W) X 4-1/4(H) X 14-7/16(D)in.
Weight: 04) gcse a Pie eee Ba aes 5.9kg/13 tb
Accessories
EP Adapter: 3.25023 ssn Aiea fae es aa 2 ad POE per et 1
Operating Instructions... .. . ee 1
NOTE:
Specifications and design subject to possible modification without
notice, due to improvements.

2. FRONT PANEL FACILITIES
() START/STOP switch
Depress
this
switch
when
starting
auto
play
or
when
stopping play.
2) REPEAT switch
Set this switch for repeat play.
8) DISC SIZE switch
Set this switch in accordance with the size of the record
which is to be played.
[7’’ 17] (released position):
({12’’ 30] (depressed position) :
(4) Quartz lock indicator
This lights when the platter is rotating at exactly 33-1/3
or 45 revolutions per minute.
(6) SPEED switch
Set this switch in accordance with the speed of the re-
cord which is to be played.
[33] (depressed position): For 33-1/3 rpm records
[45]
(released
position):
For
45
rpm
records
(6) Cartridge
For 17 cm EPs
For 30 cm LPs
(7) Headshell
(8) Tonearm
©SSe O98
@)ARM ELEVATION lever
Operate this lever when starting manual play or when
temporarily suspending play.
ANTI-SKATE control
This is rotated when performing the anti-skating adjust-
ment.
(1) Arm rest
This serves to hold and clamp the tonearm, When
moving the tonearm, release the clamp.
(2 Tracking force adjustment weight
This is used when adjusting the tracking force.
(3) Platter
(4 Platter mounting shaft
(15) Rubber mat
(6) EP adapter
This is used when playing records without a ‘‘middle.”’
(7) Cabinet
Dust cover

3. DISASSEMBLY
3.1 PANEL AND BASE
In removing the panel, follow the below listed
steps in the order given. Using any unnecessary
force will result in bending the springs or damaging
other parts.
Panel removal steps
1. Remove the headshell and weight assembly,
and the weight shaft assembly.
The weight shaft assembly is removed by
loosening screw (hexagone socket screw) and
the headshell by loosening screw @.
2. Lift off the turntable platter.
Turntable
platter
Dust cover
3. Loosen insulator attachment screws @ and
remove the insulator. (Do not mix the color-
coded float springs. They must be replaced
with their original insulators during reassemb-
ly.)
. Set the record size selector switch to ‘‘380cm’’.
. Release the arm clamp and move the tonearm
as far as it will go toward the center. Then
rotate the motor center shaft clockwise return-
ning the tonearm to the arm rest. Stop the
center shaft.
6. Remove the rear panel PU cord strain relief.
Weight assembly
Weight shaft ©
assembly
3
a Rubber bush
AA.
~ Tonearm
section
Ground wire
ise Insulator
Le
Fig. 3-1 Disassembly

7. Unplug the 2P, 2P and 6P connectors.
8. Completely remove the PU cord from the panel.
9. Lift up the headshell end of the tonearm,
and taking care not to damage the tonearm,
remove it from the panel. (Hold the tonearm
steady.)
3.2 D.D MOTOR ASSEMBLY
After the panel has been removed, loosen the
three motor attachment screws © and remove
the motor.
3.3 TONEARM SECTION
Remove the tonearm section by taking out the
three arm base attachement screws @ and one
ground wire securing screw @.
3.4 CONTROL MECHANISM SECTION
After the tonearm section has been removed,
loosen the three control mechanism attachment
screws @and remove the assembly.
Tonearm
Screwdriver \\\ ~~
3.5 TONEARM
1. Disconnect the tonearm lead wires from the
PU board (See Fig. 3-2).
Note that some of the lead wires have been
soldered to the PU board, and must be discon-
nected with care.
2. Loosen the set screw @ _ with a screwdriver
to remove the PU plate under the arm base
(See Fig. 3-3).
3. Undo the screw @securing the tonearm to the
arm base (See Fig. 3-3).
Tonearm
lead wires
Fig. 3-3 Remove tonearm

3.6 PANEL AND BASE REASSEMBLY
1.Turn the center shaft clockwise so that the
mechanism assembly is set to the reset posi-
tion.
2. Hook the driver lever spring to the panel boss.
3. Lift the forward of the panel and plug in the
2P and 6P connectors.
4. Clamp the tonearm in the arm rest and push
the START/STOP buttom.
Driver lever
Boss ’
| Le |!
t
i
I
h
il
i lever i
Driver te g
spring ‘S) |
wh
0®@
| flee
aL of {A
B tl Inlz
Seno | BLILE
ee
| Ee -
ie
;
5 a y
Fig. 3-4 Spring positioning
. Attach the PU cord stopper.
Attach the insulators. (Make certain the color-
6.
coded float springs are attached to the correct
insulators.)
7. Attach the weight shaft assembly.
Start lever
Fig. 3-5 Positioning the spring

4. TROUBLESHOOTING
Use the following directions to find the cause of
each type of breakdown. Improper adjustment
units should be completely readjusted.
« DOES NOT LEAD IN
Motor does not rotate.
;
™m n
Arm clamp is not released.
YES
Depression in EV rubber sheet.
m
”
Tracking force is too heavy.
YES
Insufficient torque on the lead-in
latch. (See section 1)
PU plate is not properly attached.
=» DOES NOT REPEAT
Repeat switch is not ON.
The start lever unit pin is separated
from the driving lever unit section.
(See section 2)
Control lever SP is weak.
Section 2
As shown in figure 4-2, if the start lever unit
pin is out of line in the direction of @) , repeat will
not operate. If it is too far in the direction of (B) ,
the unit will not start. In these cases, assemble
referring to the method of joining the panel and
bottom panel (lid).
NO Refer to the ‘‘Motor does not rotate’”’
section.
Section 1
As shown in figure 4-1, if the force required
to turn over the lead-in latch is less than 180g at a
point 13mm from the center, band the click leaf
spring toward until the force is 180 — 320g.
Bend
“(180 — 320g)
Click leaf spring
EV cam
Fig. 4-1 Adjustment of lead-in latch with insufficient
torque
Driving lever (B)
Orn Pin
Driving lever spring
Surface Ax
ras ~ '
Control U Start lever unit
base
Fig. 4-2 Misaligned pin of start lever unit

= REPEAT FUNCTION IS REPEATED
Separate the panel section and bottom panel
and, as shown in figure 4-3, apply a tension of
10g to the start lever unit pin in direction(A) If
the repeat function operates, the selector and reset
plate sections are not moving properly. If the unit
stops, the driving lever (B) is not moving properly.
Driving lever (B) is not moving pro-
perly.
Start lever is not moving properly.
YES
Selector is not moving properly.
(See section 3)
—_ 15 @
Sub-panel
Start
lever unit
(A)
A)
Fig. 4-3 Check of repat operation.
Driving lever (B) shaft is bent.
Start lever is warped.
Plastic protrusions on cut surfaces of
the sub-panel of the selector slide
section,
Protrusions on reset plate pressure
pin.
| Reset plate SP is weak.
Section 3
If
there
are
protrusions
remaining
from
the
original-pressing
process
on
surfaces
@,®@),
and
(of
the
sub-panel
which
slides
with
the
selector,
the
movement
of
the
selector
will
be
adversely
affected.
Therefore,
these
protrusions
must
be
removed
(Fig.
4-4).
Section
4
If there are plastic protrusions on the pressure
pin section of section (D) of the reset plate, these
protrusions will come in contact with the lower
surface of the driving panel when the reset plate
moves in direction (E) and the movement of the
reset plate will be adversely affected. Therefore,
these protrusions must be removed (Fig. 4-4).
s AUTO-RETURN DOES NOT WORK
Section 5
After performing the return operation, if the
curved section of the signal plate and curved sect-
ion of the starting plate are not in contact with
surfaces ‘) and respectively of the cam, reset
will be incomplete and the starting position will
be late. As a result, the return function may not
operate at times. In this case, bend the signal
plate C)so that dimension A is 0.5mm or larger.
8B
pas Sub-panel
De
Se
Boot:
REN Reset plate SP
< NO
SQ ~~ Reset
plate
e
Fig. 4-4 Improper movement of selector
Signal plate
j
y
/
Cam
At least 0.5mm
Fig. 4-5 Incomplete reset of starting and signal plates

Change in starting position adjust-
ment.
YES
Starting plate does not follow the NO Too much grease between the signal
signal plate. plate and the cam.
YES
Inner diameter of the starting plate
hole is small.
Protrusions on the caulk section of
the starting plate hole.
Not enough grease between the
starting plate and signal plate.
The curved section of the signal
plate is deformed.
After starting, incomplete reset of the
signal plate. (See section 5)
YES
The inner areas of records can not 7
batracked: Arm lead wire is caught on something.
YES
PU cord is touching the PU plate.
Operator of the detection lever is
not smooth.
Looseness in the PU plate attach-
ment.
# RETURN IS FAST (RETURN AT 1mm PITCH)
Protrusions on the pinion gear section
(See section 6)
Section 6 ks =a Pinion gear
If there are tough areas of plastic protruding @— Protruding
from the (A) section of the protruding section of section
the pinion gear, the return function may operate
at a pitch of only 1mm. In this case, remove the Fig. 4-6 Elimination of pinion
plastic protrusions completely (Fig. 4-6). gear protrusions

= TONEARM DOES NOT LOWER IN CORRECT POSITION
Incorrect adjustment.
YES
PU plate operation is not smooth. PU lever A and PU lever B are not
ore moving smoothly.
E
Location of stylus was changed
during cartridge replacement.
= RECORD SIZE SELECTOR DOES NOT WORK
Tonearm descends at 17cm location when
record size selector is set at 30cm.
Size select SP is warped.
YES
Size select lever does not operate
smoothly.
Tonearm descends at 30cm location when record
size selector is set at 17cm.
Size select return SP is warped.
YES
Select lever does not operate smooth-
ly.
Size select lever is warped.
Plastic protrusions in auto-stop
mechanism resin section of the select
lever sliding surface.
Plastic protrusions on the select lever.
Index cam does not operate smoothly. No Index cam stopped hooked section
has fallen over.
YES
Size select SP is weak.
= MOTOR DOES NOT ROTATE
2P, 2P or 6P connectors are not at-
tached.
YES
Connector(s) is not properly installed.
10