JVC QLF-6 Service manual
JVC
MODEL
taL-Fe
QUARTZ
TURNTABLE
FULLY AUTOMATIC
No. 2464
. FEB. 1979
Contents
1. Specifications ...................................................................
2. ServicePrecautions................................................................
Features.......................................................................
4. NamesofPartsandTheirFunctions.....................................................
5. Replacement Procedures
(1) Stylus..................................................................
Headshell "
(2)
(3) Cartridge..............................................
(4) Motor..................................................................
(5) HO/VODampingKnobs "
6. Lubrication
(1) HO/VODampingMechanism ..................................................
(2) Motor..................................................................
(3) FullyAutomaticMechanism...................................................
7. Adjustment Procedures
(1) ~UARTZ LOCK/PITCH CONTROL Meter ........................................
(2) OuartzLockAdjustment
Tonearm Section
(3) HeadsheliAngle "
(4) TonearmElevator..........................................................
(5) Overhang ...............................................................
(6) Lead-in.................................................................
(7) Lead-out................................................................
(8) TrackingForce...........................................................
(9) Anti-skating.............................................................
(10) HO/VODamping .........................................................
F6BlockDiagram .............................................................
8. OL-
9. Troubleshooting Charts
Platter does not rotate.
(1)
Platter rotates at high speed. .................................................
(2)
Pitch Control operates abnormally. .............................................
(3)
10. Exploded Views and
10-(1) Cabinet & Mechanism Ass
10-(2) Mechanism Ass
10-(3) TonearmAss
11. Printed Circuit Board Ass
11-(1) MDC-938G .............................................................
11-
(2) TPS-206 ...............................................................
12. Accessories List .................................................................
13. OL-
14. PackingMaterialsandPartNumbers....................................................
15. Parts List with Specified Numbers for Designated Areas. .
F6 Schematic Diagram ..........................................................
Parts List
y and Parts List
..................................................... 8
Back page
Pages
'" 6
OL-
No. 2464
1 -
Specifications
MOTOR SECTION
(These specifications apply only to the quartz lock mode.
Motor
Servo system
Drive system
Speeds
: Core less
FG servomotor
: Phase-
oscillator
: Direct drive
: 33-
, DC type
locking to the quartz
1/3
Fine pitch
adjustable range
Wow and flutter
to-noise ratio
Signal-
Speed detection
Starting torque
Speed deviation
Load characteristics
Drift
Power characteristics
: :!: 6 % (at the pitch
: 0.
025 % (WRMS)
: More than 78 dB (DIN-
control mode)
: Frequency generator
: More than 1.
: Within 0.
2 kg-cm
002 %
: 0 % (with 170 g total tracking
force)
: 0.0001 %/H
: 0 % (:!: 10 V)
Temperature
characteristics
Platter
TONEARM SECTION
Type
: 0.
00005
7 cm
: 32.
: Statically-
%tc
balam;ed oil-damped
tonearm
Effective arm length
Overhang
Weight range
including headshell
: 233 mm
: 15 mm
: 13 - 20 g
24 g (when using the provided
sub-counterweight)
CARTRIDGE SECTION
(Except for USA, Canada and U.
Type
Frequency response
: Moving magnet (MD-l025EB)
: 10 Hz - 25 000 Hz
Output : 3 mV (1 kHz)
Channel separation
Load resistance
Compliance
Stylus
Optimum tracking force: 1.
GENERAL
Power consumption
Dimensions
Weight
Accessories
EP adapter
Sub-counterweight
: 25 dB (1 kHz)
(using the test record TRS-
: 47 - 100 k-ohms
: 10 x 10
30 x 10
: DT-
(diamond
6 cm/dyne (dynamic)
6 cm/dyne (static)
Zl EB
, 0.3 x 0.7 mil.
, elliptical)
75 g :!: 0.
25 g
: 15W
: Height 14.
cover)
Width 45.6 cm
Depth 40.
(Since the dimensions show only
the design measurements
sideration is requ
installing the unit in a limited
space such as a rack
: 11 kg (without the packaging)
: 1
Place the adapter on the center
spindle when playing a record
having a bigger diameter center
hole such as a doughnut record.
: 1
2 cm (with closed
0 cm
, con-
ired when
, etc.
2. Service Precautions
. Be sure to use JVC standard parts.
. When
. Be sure to adjust motor speed with the u nit level
. When repairing circuit board with the heat sink
repairing the speed control circuit board con-
nect the m938
to the transistor used.in the platter drive section.
G motor in order to prevent damage
otherwise fluctuations which make adjustment impos-
sible may occur.
, attach mobile heat-sink to prevent the tran-
moved
sistor temperature from rising.
re-
Design and specifications subject to change without notice.
3. Features
. Newly developed oil-damped tonearm
trackability.
Highly sensitive, new gimbal'support tonearm system.
. Double-
resonance coreless motor give high reliability.
. Extra-
the mat
Howling margin is greatly
super-compound (type-
quartz servo circu it and high torque
heavy aluminum diecast platter (2 kg including
, inertia 330 kg/cm
improved with the new
l) board used as the base.
Operation buttons and controls are positioned at the
front for easy operation.
. NR-
type headshell with minimum
ployed.
Moving-magnet cartridge with a elliptical stylus.
Fine pitch control allows adjustment
(approx. a half note).
. Quartz lock/Pitch control meter for convenient speed
check.
Fully automatic mechanism.
assures high
, non-
resonance is em-
within:!: 6 %
QL-
No. 2464
4. Names of Parts and Their
Dust cover
Center spindle
Mat
Functions
Platter
1. OIL
DAMPED TONEARM
Ordinarily tonearms have a resonance frequency of
between 5 to 10Hz.
tonearm is too high
arm with the record groove cannot be obtained be-
cause the tonearm resonates at a frequency generated
If the peak of the range of a
, accurate tracking of the tone-
by ambient vibrations or sound pressure, or the tone-
arm can be influenced by adverse conditions of the
record such as warps
, etc. The
OIL DAMPED
Fig. 1
TONEARM i~ designed to suppress the range of
resonance by maintaining a low resonant point of
the tonearm to prevent howling. With this OIL
DAMPED TONEARM
, accurate tracking of the
record groove as well as a good resistant character-
istic to howling is possible
proveved SIN ratio. I
quality, the OIL
DAMPED TONEARM plays an
, thus resulting in an im-
n order to improve the sound
important role.
QL-
No. 2464
2. HQ
DAMPING knob
This controls the horizontal movement of the tone-
arm while aiding to keep the tonearm
s resonating
point low. Set the knob to the same indication
ber as the optimum tracking force of this unit.
3. VQ
DAMPING knob
This controls the vertical movement of the tonearm
while aiding to keep the tonearm
low. Set the knob to the same
the optimum tracking force of this unit.
4. Speed
select knob
s resonating point
indication number as
Select a proper position of the speed select
accordance with the rpm of the record.
1/3 rpm record (LP)
33-
45rpmrecord(EP).............
5. QUARTZ
QUARTZ LOCK:
Depress the button to the
speed in the quartz lock mode. In this case
meter lights green.
PITCH CONTROL:
Depress the button a second time to obtain
P ITCH CO NT RO L position (---) in order to
form fine pitch adjustment for the sound meeting
your preference. I
6. PITCH
When the QUARTZ
select button is set to the QUARTZ LOCK position
the meter is green-
When the QUARTZ
select button is set to the
tion
the PITCH
orange-
7. PITCH CONTROL knob
Fine pitch
QUARTZ
set to the PITCH CONTROL position. Pitch
ment
deflecting to the left (#)
cates an increase to the accurate 33-
and the deflection to the right (b) means a decrease.
8. ANTI-
This device cancels out the centripetal force that
pulls the tonearm to the center of the platter. This
prevents the stylus tip from skating toward the
center of the platter and at the same
any excessive stylus tip force on the inner
the record groove. Use the 8 marked dial when
ploying a spherical stylus. Use the marked dial
when employing an elliptical stylus or a SHIBATA
stylus.
Turn the dial to the
force dial.
LOCK/PITCH CONTROL select button
QUARTZ LOCK position
) for playing a record at an accurate rotation
n this case, the meter I ights orange.
CONTROL meter
LOCK/PITCH CONTROL
lit and the indicator displays "
LOCK/PITCH CONTROL
PITCH CONTROL posi-
, pitch control can be
performed by turning
CONTROL knob and the
I it.
#6 % means +6 %
% means -
b6
control can be performed with the
LOCK/PITCH CONTROL select button
range is
SKATING knob
6 %
:!: 6 %. The
indicator in the meter
from the center (0) indi-
1/3 or 45 rpm
time eliminates
same number as on the track ing
num-
knob in
33"
45"
, the
the
per-
meter is
adjust-
wall of
em-
REPEAT knob
9.
Decide how many times you want to re-
record by using this knob.
When you set the knob
listen to the
to " , the record will continue to play repeatedly.
Note: This knob cannot be
1 - 0 or 0 - 1
pressed with the power cord
from the outlet. For this
in the section "
to record playing
10. START/REJECT buttons
When you start playing a record
ST ART
button. The
the position of the first groove of the
selected and gently lowers itself onto the surface of
the record to play it.
record, depress the REJECT button. The
, returns automatically to its rest and the platter
lifts
stops rotating.
, however, the
number of repeats
respond ing number
REPEAT knob has been set for a
, the tonearm
of prepeats before the platter
stops rotating.
Note: When the dial of the repeat
numbers other than "
set to
continues to rotate and the
be turned off even though you depress
turned to indicate from
if the START button is de-
disconnected
, refer to the note
Necessary procedures prior
" on page 2.
, depress the
tonearm moves automatically
When you stop playing the
performs the cor-
knob has been
, the platter
power will not
REJECT button or even if the
record has
power to be turned off after the
played once
to the "0" mark.
RECORD SIZE select knob
11.
Set the knob to the corresponding
size of the record before you play it.
30 cm diameter record. . . .
25 cm diameter record. . . .
17cmdiameterrecord...... "
12. Arm lifter lever
This is
used when you want to
gently or gently lower it.
UP" position
when you pull it to the "
be lowered down gently onto the record surface.
finished. When you want the
, be sure to set the repeat knob
position to the
17"(7")
raise the tonearm
When you push it to the
, the tonearm will be lifted up,
DOWN" position
record pre-
tonearm
the
playing
record has
30" (12"
25" (10"
and
, it will
QL-
No. 2464
5. Replacement Procedures
1)
5-(
Replacement of the stylus can be
inserting the stylus plug (A) into the
cartridge. Service life of the stylus
unit (DT-
ing on the record condition (dirty record groove etc.
Stereo LP record (30 cm) . . . Approx. 300
Stylus are disposable items. Therefore, it is recommended
to buy a supply of styli when you buy the unit.
purchasing them
Stylus
Stylus replacement (See Fig. 2)
easily made by simply
jack (B) of the
employed for this
Zl EB) is generally as follow; varying, depend-
- 500 hours
When
, specify the DT-Zl EB (JVC standard).
5-(2) Headshell
Removal and mounting of the headshell (See Fig. 3)
Turn the connector nut in the direction of "
the headshell from the tonearm. Turn it in the direction
A" to remove
of "B" for mounting the headshell.
5-(3) Cartridge
Mounting the cartridge (See Fig. 4)
1. Remove the 2 screws securing the cartridge onto the
headshell.
nstall your cartridge onto the
2. I
headshell provided or
onto a headshell of your selection.
3. The
headshell lead wires are color-coded as follows
connect them correctly.
White(+)
L Red(+).......
BlueH " " LE Green(-
4. Mount the
and leave the set screws slightly loosened
completing the "
tighten them firmly. After this adjustment
that the conditions concerning the 3 adjustments on
page 5 and 6 are satisfactorily met.
5. After each cartridge replacement, be sure to perform
the 4 adjustments described on page 9.
cartridge properly onto the
, then, after
Overhang adjustment
" (See page 9)
headshell
, be sure
(4) Motor
Green: to RE or R- of cartridge
Blue: to LE or L- of cartridg
Red: to R+ or R of cartridge
White: to L+ or L of cartrige \
Fig. 2
Fig. 3
, ~s~"'-
Cartridge
with stylus
Headshell
lift "0"
Fig. 4
How to remove the motor (Fig. 5)
Remove the motor in
no need to remove the mechanism
the following sequence. There is
s base.
1. Remove the stopper, main gear and spring
to the motor plate.
2. Disconnect the plug connecting the motor with the
speed control circuit board.
3. Remove the
4. Lift the trip lever as shown in the figure while taking
4 screws securing the motor.
care not to deform it and remove the motor while
tilting it.
5. Mount the motor, in the reverse order.
QL-
No. 2464
attached
Fig.
(5) HQ/VQ
Damping Knobs
When replacement of VQ or HQ damping knob becomes
necessary, do it in the following sequence.
. How to replace the HQ damping knob (Fig. 6)
1. Remove the 2
screws securing the HQ damping knob
and remove the knob.
2. Turn the HQ controller clockwise until it
stops.
3. Clamp the tonearm to its rest.
4. Mount the new
troller with the
with the index line. Secure it with the 2
5. After replacing it
the section "
. How to replace the VQ damping knob (Fig. 6)
Replace in the same
replaced.
HQ damping knob on the HQ
indication "
, perform adjustment
How to use
way as the HQ
3" on the knob
" on page 4.
damping knob is
con-
aligned
screws.
referring to
6. Lubrication
6-(1) HQ/VQ
QL-F6 turntables are completely adjusted at the factory
prior to shipment. The
repaired imd it is
it malfunctions.
Damping Mechanism
damping mechanism cannot be
recommended that it be
replaced if
Ha damping knob
Ha controller
Index line
va controller
Screws
"t.
Fig. 6
va damping knob
6-(2) Motor
The motor needs no lubrication.
6-(3) Fully Automatic
Apply high quality grease to connecting and sliding parts
after they are replaced.
Mechanism
7. Adjustment Procedures
Servo-motor Control
7 -(
1)
QUARTZ LOCK/ PITCH
How to use the QUARTZ
meter (See Fig. 7-
LOCK/PITCH CONTROL
Section
CONTROL Meter
QUARTZ LOCK (~):
When the QUARTZ
button (1) is
the meter (2) becomes green-
tion speed is
depressed to tbe QUARTZ
accurately controlled by phase-
LOCK/PITCH CONTROL select
LOCK position
lit. In this mode the rota-
locking to
the quartz oscillator frequency. This means that correct
1/3 or 45 rpm is
33-
obtained. The indicator (2) of the
meter displays "
PITCH CONTROL
When performing fine pitch adjustment
QUARTZ
to the PITCH
comes orange-lit. In this mode
can be performed by
knob (3) within a
the (+) direction (counterclockwise)
Turning it in the (-)
rpm. The meter
LOCK/PITCH CONTROL select button (1)
CONTROL position and the meter be-
, fine pitch adjustment
turning the PITCH CONTROL
range of
indication of +6 % (#)
:!: 6 %. Turning the
direction (clockwise) decreases the
, depress the
knob in
increases the rpm.
shows the re-
produced sound raised by approximately a half tone.
The -6 %
(b) indication shows the
reproduced sound
is lowered by approximately a half tone.
By making these adjustments
, record sound reproduc-
tion meeting your preference can be obtained.
Fig.
QL-
No. 2464
How to make
should indicate incorrectly (when the meter
display "
Fig.
adjustments if the pitch control meter
0" in the
QUARTZ LOCK operation). (See
does not
1. Disconnect the power cord from the outlet.
2. Remove the
3. Turning the "
platter from the motor shaft.
0" position adjusting screw clockwise
moves the indication to the right.
Turning this screw counterclockwise
cation to
Generally, there is no
tl:1e-left.
need for adjustment since
moves the indi-
proper adjustment has been performed at the factory.
Should the
indication of the meter be incorrect
adjust it in the manner above.
Adjustment of the FINE
PITCH CONTROL
meter (See Fig. 7-
Perform this meter adjustment referring to the
below after making mechanical adjustments pertaining
items
to rpm or repairing the meter circuits.
1. Function of the variable
1) VRl
(4.7k.Q):
resistors used
Connected in series with the meter and controls
the current flowing into the meter. Used to adjust
the full-scale deflection
(:1: 6 %)
of the meter.
2) VR2 (4.7k.Q).
Employed for
indicate the center position "0" at 33-
or 45 rpm.
3) VR4 (47 k.Q):
There is no need to
because of the automatic
ever, adjustment in the following order is
sary after the motor is
repaired. Turning VR4 to the right
seen from the circuit board
and turning it to
increases the speed and
unlocked
Adjust VR4 to
adjusting the pointer of meter to
1/3 rpm
adjust this variable resistor
adjusting system. How-
neces-
replaced or the circuit is
(clockwise) as
decreases the speed
the left (counterclockwise)
unlocks it. When it is
platter rotation becomes unstable.
its middle position where the
rotation speed is stable and does not increase
or decrease.
4) VR5 (22 k.Q):
For adjusting the oscillation frequency of the
pitch control. Adjust V R5 (to
position) with the speed
until the correct speed is obtained.
5) VR6 (10k.Q):
Pitch control located on front panel.
For detail
, see PITCH CONTROL on page 6.
selector set to "33-1/3"
near its middle
Fig.
2. Adjustmerrt method (See Fig.
7-C)
Perform mechanical adjustment for the meter to indicate
the center position before connecting to an AC outlet
for electrical adjustment.
1) Adjustment of the
oscillation frequency of the non-
stable multivibrator
Connect a
frequency counter to TP-
l with the
QUARTZ LOCK/PITCH CONTROL select button
while set in the
PITCH CONTROL position. Turn
VR5 with VR6 set to near the center position until
a frequency counter re
ading of 172.
8 kHz obtained.
2) Center indication adjustment of the meter.
Turn VR2 with the speed select knob set to 33-
until the meter
, set the speed select to
Then
indicates the center position "
45 rpm and the meter
1/3
indicates the center position "
Confirm again that the meter
tion at the 33.
3) Full-scale deflection
1/3 rpm.
(:1: 6 %)
Turn VR6 until an oscillation frequency of 183.
(+6 %) is obtained. Turn VRl until
indicates center posi-
adjustment
2 kHz
the meter correct-
ly indicates +6 %.
Turn VR6 until an oscillation frequency of 162.4 kHz
(-6 %) is obtained and confirm that the meter correct-
Iy indicates -6 %. Deflection of the meter out of the
-6 % zone
indicates -6 %, if the meter deflection is insufficient
for -6 %. I n this condition
out of the +6 % zone may occur
. The meter adjustment can be performed
stroboscope
is allowable. Turn VR 1 until the meter
, deflection of the meter
, but is allowable.
using a
, even
if measuring equipment
is not
available. Turn VR5 with VR6 set to the center posi-
tion until the stroboscope appears
the center indication adjustment
manner as when
employing a frequency counter.
It is not possible to perform the full scale
adjustment and adjustment of VR 1 is
stationary. For
, follow the same
deflection
unnecessary.
QL-
No. 2464
7 -
(2) Quartz Lock Adjustment
This adjustment is
pairing
VC4046 (IC1) or
voltmeter or tester having an
20 kD,/V . Connect it between Pin 10 and the ground
terminal of ICl and turn VR4 until a
:1: 0.
5 V is obtained.
Slight adjustment errors are
automatic lock-
rectly performed with a
1 k - 5 kSt
some manner, such as using an emitter-
necessary only after replacing or re-
replacing VR4. Prepare a
impedance of more than
reading of 3
negligible thanks to the
in type IC. The
adjustment can be cor-
tester having an
impedance
if an impedance conversion is performed in
follower circuit.
Tonearm Section
7 -(3)
If the headshell is not horizontal and the stylus tip is not
perpendicular to the record surface
screws as shown in the
shell to adjust the stylus to be at right angles
the platter.
Be sure to retighten the screws
completed.
Headshell Angle
Headshell mounting angle adjustment (See Fig. 8-
, loosen the lock
illustration and move the head-
with
Eye-measurement is sufficient.
after the adjustment is
(90
Fig.
Fig.
7-(4) Tonearm 8evator
. Tonearm
The optimum. clearance between the stylus tip and the
record surface is about 6 mm when the tonearm is
ported by the tonearm elevator. Turning the
screws clockwise lowers the
elevator and counterclockwise increases it.
elevator height adjustment (See Fig. 9)
sup-
adjusting
height of the tonearm
Fig.
Fig. 9
QL-
No. 2464
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