Technics SL-QX300

SL-QX300
m@ MEASUREMENTS AND ADJUSTMENT
e Arm-lift height adjustment
The arm-lift height (distance between the stylus tip and the record surface
when the cueing control is at the ‘“’ ¥ ” position) has been adjusted at the
factory to approximately 5 to 7 mm (3/16 ~ 9/32”). (Fig. 14)
If the clearance is too narrow or too wide, turn the adjustment screw clock-
wise or counterclockwise. (Fig. 15)
Clockwise rotation
— distance between the record and stylus tip is decreased.
Counterclockwise rotation
— distance between the record and stylus tip is increased.
5mm ~ 7 mm (3/16" ~ 9/32")
e Adjustment of automatic start position
If the stylus does not land in the lead-in groove, adjust as follows.
1. Clamp the tonearm to the arm rest. Adjustment
2. Remove the rubber cap. (Fig. 16) screw
3. Turn the screw with a screwdriver, clockwise or counterclockwise as
necessary.
If the stylus tip sets down too far in the recorded groove.
— turn counterclockwise.
If the stylus tip sets down outside of the record.
— turn clockwise.
Adjust so the stylus tip lands 1 ~ 2 mm in from the edge of the record.
e Adjustment of automatic return position (Fig. 17) Auto-start
(Remove the rubber cap.) adjustment screw
1. Put the stylus protector on the cartridge.
2. Move the tonearm toward the center of the record.
The auto-return adjustment screw will appear.
If the tonearm tends to return to the arm rest before the play has finished.
— turn counterclockwise.
If the tonearm fails to return after the final groove.
—
turn
clockwise.
:
Auto-return,
\
adjustment screw
e Speed adjustment (pitch control) (Fig. 18)
New G@LS (Quartz Linear Synthesizer) circuitry permits continuous analog
pitch adjustment up to about + 6% while maintaining quartz locked accuracy.
When the pitch control is at the center position, the turntable rotates at
standard speed (33-1/3 or 45 rpm).
Turn off the reset switch, then adjust the pitch control as desired, referring
to the scale markings. TC Se precr contra
Note: 1) Turn reset switch on to play records at standard speed. 2
2) When the reset switch is on, the turntable rotates at standard speed, eS
so pitch is not adjustable. If the reset switch is turned on after
changing the pitch, the turntable will return to standard speed.
3) The strobe is quartz locked with the variable pitch settings, so the
strobe markings always appear to be standing still.
e Pitch control adjustment (reference frequency) (Fig. 19)
. Remove the turntable platter and panel cover. (Refer to ‘How to remove
the cabinet and bottom board”’.)
. Set the pitch control knob to the center position.
. Connect the oscilloscope to terminal 11 of IC302.
. Push the on/off switch to turn it “on”.
=
ar WN
. Turn VR301 so that the frequency of output waveform is 523.64 kHz ~
524.68 kHz (1.9097 us ~ 1.9059 us).
Mm TROUBLE SHOOTING
e Conditions of the set
Case 1: Refer to Fig. 20. (Checking each part in stop mode.)
(1) Remove the turntable mat and turntable platter.
(2) Remove the panel cover.
(3) Push the on/off switch to turn it “on”.
y Power source and pitch
Case 2: Refer to Fig. 21. (Checking each part in operation Zi) control circuitP.C.B.
mode.)
(1) Remove the turntable mat and turntable platter.
(2) Remove the panel cover.
(3) Remove the audio insulator (front left).
(4) Set the tester lead wire through the hold (audio in-
sulator) in the bottom board, and connect the lead
wire clip to the checking part.
(5) Connect the ground terminal of the tester to the GND
terminal of the phono cable.
(6) Put on the turntable platter, turntable mat and record.
(7) Push the on/off switch to turn it ‘on’.
(8) Push the start/stop switch.
Case 3: Refer to Fig. 22. (Checking each part in stop and Testr
operation modes.) (Voltmeter and oscilloscope)
(1) Remove the cabinet and bottom board.
(2) Remove the start/stop switch P.C.B.
(3) Remove the on/off switch.
(4) Connect the ground of control circuit P.C.B. to the
automatic mechanism plate with wire.
(5) Push the on/off switch to turn it ‘‘on” and then check
each part in stop mode.
(6) When checking in operation mode, connect the tester
lead wire to the checking part. Next, put on the
turntable platter, mat and record, then push the
start/stop switch.
Start/stop switch
Power source and pitch
control circuit P.C.B.
On/off switch