Sony CDP-470 - Optical Pick-up Focus;Tracking Gain Adjustment

Focus/Tracking Gain Adjustment
A frequency response analyzer is necessary in
order to perform this adjustment exactly.
However, this gain has a margine, so even if it is
slightly off, there is no problem. Therefore, this ad-
justment is not recomended generally to be per-
formed.
Focus/tracking gains determine the pick-up follow-
up (vertical and horizontal) relative to mechanical
noise and mechanical shock: when the 2-axis device
operate.
However, as these reciprocate, the adjustment is at
the point where both are satisfied.
® When gain is raised, the noise when the 2-axis
device operates increases.
@ When gain is lowered, it is more susceptible to
mechanical shock and skipping occurs more easily.
@ When gain adjustment is off, the symptoms below
appear.
Tracking
@ The time until music starts
becomes longer for STOP
> PPLAY or automatic
selection (Ké4 PPE buttons
pressed. (Normally takes
about 2 seconds.)
low or high
@ Music does not start and
disc continues to rotate
for STOP >DPLAY or
automatic selection (h4¢€
bP i buttons pressed.)
@ Disc table opens shortly
after STOP >DPLAY.
@ Sound is interrupted dur-
ing PLAY. Or time count-
er display stops progress-
ing.
low or high
e More poise during 2-axis
device operation.
The following is a simple adjustment method.
— Simple Adjustment —
Note: Since exact adjustment cannot be performed, remem-
ber the positions of the controls before performing the
adjustment. If the positions after the simple adjust-
ment are only a little different, return the controls to
the original position.
oscilloscope
(DC range)
Procedure:
main board
aoe
TP (FEI) a +
$
TP (FEO) | =
TP (TE!) Ome -
TP (TEO)
1. Keep the set flat.
If the set is not horizontal, this adjustment
cannot be performed due to the gravity against
the 2 axis device.
2. Insert the disc (YEDS-18) and press
button.
3. Connect the oscilloscope to TP (FEI) and TP
(FEO).
4, Adjustment RV203 so that the waveform is as
shown in the picture below. (focus gain adjust-
ment)
> PLAY
VOLT/DIV: 100mV
TIME/DIV: 2mS
—100mV
—OvV
® Incorrent Examples (DC level is quite different
from the adjusted waveform) (below)
low focus gain
VOLT/DIV: 100mV
TIME/OIV: 2mS
— 250mV
—OV
high
focus
gain
VOLT/DIV:
100
TIME/DIV: 2mS
5. Connect the oscilloscope to TP (TEI), TP (TEO).
6. Adjust RV204 so that the waveform is as shown in
the picture below. (tracking gain adjustment)
—oOv
@ Incorrect Examples (fundamental wave appears)
low tracking gain
gq OV
high tracking gain
(higher frequency of the fundamental wave
than above)
—oOvV
VOLT/DIV:
TIME/DIV: 2mS
; VOLT/DIV:
mas TIME/DIV: 2mS
VOLT/DIV:
TIME/DIV: 2mS
CDP-270/470
700mV
700mV
700mV
main board
Adjustment Location:
TP ate t
TP (REG)
TP (RF) e—
\ j (Gno) er
rs RV203 —
TP TP ( eee e f
(FEO)_TP OS TP (PLCK)
PN om es
Rv201 TP ee TP (ASY)
ey :
ale] | a,
Te e} (PCK]}
— Component Side—
47 ie oO}
Sr V202