Sony D-5 - Focus;Tracking Gain Adjustment

ress the MB key. Confirm that disc rotation
ops. If not, press the jj key again, longer.
fter adjustment, release service mode (see
age 9-11).
1xent Location: main board
TP! (RF)
FOCUS/TRACKING GAIN ADJUSTMENT
Focus/tracking gain determines the pick-up follow-
up (vertical and horizontal) relative to mechanical
noise and mechanical shock when the 2-axis device
operates.
However, as these reciprocate, the adjustment is at
the point where both are satisfied.
@ When gain is high, the noise when the 2-axis device
operates increases,
@ When gain is low, it is more susceptible to mecha-
nical shock and skipping occurs more easily.
This adjustment is to be performed when replacing
the following parts:
FOP, RV501 (focus gain VR), RV502 (tracking gain
VR)
Adjustment Method:
— Focus Gain Adjustment —
This adjustment is not performed.
If the focus gain VR RV501 is turned, set to me-
chanical center (see Fig. 6).
MIN (low gain} MAX (high gain)
/
: VR contact point
| When VR contact point is
here, it is at mechanical center.
(top
view)
(side
view)
Fig.
6
Mechanical
Center
(seen
from
chip
mounted
side)
— Tracking Gain Adjustment —
(perform at normal operation)
oscilloscope
(DC range)
main board é
———,
TPS (TE) O=_———————_0 +
Ly
1, Place the set level, horizontally (upper panel
can be facing down). (If the set is not level, the
2-axis device will be weighted and adjustment
cannot be done.)
2. Connect the oscilloscope to main board test
point TP9 (TE).
D-5/D-50 D-5/D-50
3. Turn the power switch on, insert the disc
(YEDS-1) and press the > Bikey.
4. Turn RVS502 slightly clockwise (tracking gain
drops) and obtain a waveform with a funda-
mental wave (waveform has large waves) as in
Figure 7.
5. Turn RV502 slowly counterclockwise (tracking
gain rises) until the fundamental wave disap-
pears (no large waves) as in Figure 8.
6. Set RV502 to the position about 30° counter-
clockwise from the position obtained in step 5.
If RV502 contact point location is within the
range shown in Figure 6 @ , tracking gain is
too high. In this case, readjust from step 4.
7. Select AMS mode with the MODE button,
continuously press pp or kéq key and observe
the 100 track jump waveform. Check that no
traverse waveform appears for both pp and
kK¢q directions. (See Figures 9 and 10.) It is
acceptable if the traverse waveform appears
only now and then, but if it appears constantly,
raise tracking gain slightly and check step 7
again,
8. Check that there is not an abnormal amount
of operation noise (white noise) from the 2-axis
device. If there is, tracking gain is too high, so
readjust starting with step 4.
The waveforms are those measured with the oscil-
loscope set as shown below.
VOLT/DIV: 1V
TIME/DIV: 5 mV
@ Waveform when tracking gain is lowered.
Fundamental wave appears (large waves).
Fig. 7
Adjustment Location: ma
@ Waveform when fundamental wave disappears (no
large waves).
TP9 (TE)
fect
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silk
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OV
Fig. 8
@ Waveform with no traverse waveform during 100
track jump. (Brake application is smooth because
of adjustment).
100 track jump waveform
Fig. 9
RV501
@ Waveform with traverse waveform during 100 :
(focus gain)
track jump. (Brake application is poor because
of low tracking gain.)
100 track jump traverse waveform
waveform
Fig. 10