Technics SL-PC25

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(5)
FOCUS GAIN ADJUSTMENT
. Connect the servo gain adjuster to the player (see page
15).
Set the servo gain adjuster’s gain switch to position “2”
and the ON/OFF switch to ON.
Set up the AF oscillator output for 825Hz, 150 mVp-p,
and connect it across the OSC and GND terminals on the
servo gain adjuster.
Connect oscilloscope’s CH. 1 and CH. 2 probes to the
servo gain adjuster’s TP1 and TP2 terminals, respectively
(TP3 is GND).
Oscilloscope setting: VOLT .......... 100 mV
(both channels)
SWEEP......... 0.2 ms.
Input coupling... AC
. Play the test disc (SZZP1014F or SZZP1054C).
. Set the servo gain adjuster’s gain switch to position ‘’3”,
and you will see a 825 Hz signal on the oscilloscope.
Adjust VR104 until the signal amplitudes on both
channels become identical to each other.
. Set the gain switch back to position “2”.
TRACKING GAIN ADJUSTMENT
. Set up the AF oscillator output for 1.1 kHz, 150 mVp-p,
and connect it across the OSC and GND terminals on the
servo gain adjuster.
Connect oscilloscope’s CH. 1 and CH. 2 probes to the servo
gain adjuster’s TP1 and TP2 terminals, respectively
(TP3 is GND).
Oscilloscope setting: VOLT.......... 100 mV
(both channels)
SWEEP......... 0.2 ms
Input coupling... AC
Switch the player power ON, and play the test disc
(SZZP1014F or SZZP1054C).
Set the servo gain adjuster’s gain switch to position “1”,
and you will see a 1.1 kHz signal on the oscilloscope.
Adjust VR102 until the signal amplitudes on both
channels become identical to each other.
. Set the gain switch back to position “2”.
(6) FOCUS OFFSET ADJUSTMENT
Note: Make sure that the servo gain adjuster’s gain switch
is set to position “2”.
1. Connect the oscilloscope’s CH. 1 probe across QR MIU
(+) and QypREa (—) on the Servo P.C.B. and its CH. 2
Probe (+) to VR104’s terminal.
Oscilloscope setting: VOLT.......... 100 mV (CH. 1)
100 mV (CH. 2)
SWEEP......... 0.2 ms.
Input coupling. .. AC (both CH. 1
and 2)
Trigger mode... .NORM (trigger
CH. 1.)
Switch the player power ON, and play track 9 on the
test disc (SZZP1057C).
Trigger the oscilloscope’s CH. 1 so that the following
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