Sony CDP-C75ES - Page 8

CDP-C75ES/C85ES/C705
2-4, ELECTRICAL ADJUSTMENTS
1. Perform adjustments in the order given.
2. Use YEDS-18 disc (3-702-101-01) unless otherwise indicat-
ed.
3. Use the oscilloscope with more than 10MQ impedance.
RF Level Check
Procedure:
oscilloscope
(DC range)
BD board
an,
TP (RF) o
TP (VC) 0
1. Connect oscilloscope to test point TP (RF) and TP (VC)
on BD board.
2. Confirm that RF level and eye pattern is optimum.
Oputimum eye pattern means that shape “©” can be
clearly distinguished at the center of the wave form.
RF signal Reference Waveform (eye pattern)
RF level VOLT/DIV: 200mV
TIME/DIV: 500nS
LAK AAAAAAAAA/
AY |
AANA
BAA
A=1.2+0.3Vp-p
REFERENCE
E-F Balance Check
Procedure:
oscilloscope
(DC range)
1. Connect test point TP (ADJ) and TP (TES) to ground
with lead wire.
2. Connect oscilloscope to test point TP (TE O) and TP
(VC) on BD board.
3. Turn POWER switch on.
4, Put disc (YEDS-18) in and playback.
5. Confirm that the oscilloscope waveform is symmetrical
on the top and bottom in relation to 0V.
6. After check, remove the lead wire connected in step 1.
Note: Take sweep time as long as possible to obtain best
waveform.
RF PLL Free-run Frequency Check
Procedure:
frequency counter
al
Se
1. Turn POWER switch on.
2. Put disc (YEDS-18) in and playback.
3. Confirm that reading on frequency counter is 4.3218M Hz.
Main board
rn,
TP (PCK)
Focus/Tracking Gain Adjustment
A frequency responce analyzer is necessary in order to
perform this adjustment exactly.
However, this gain cas a margin, so even if it is slightly off.
there is no problem. Therefore, do not perform this adjust-
ment.
Focus/tracking gain determines the pick-up follow-up (ver-
tical and horizontal) relative to mechanical noise and me-
chanical shock when the 2-axis device operate.
However, as these reciprocate, the adjustment is the point
where both are satisfied.
* When gain is raised, the noise when the 2-axis device
operates increases.
* When gain is lowered, mechanical shock and skipping
occurs more easily.
* When gain adjustment is off, the symptoms below appear.
symm | Pe | Pee
* The time until music starts
becmes longer for STOP ~>
PLAY or automatic selection. :
(Kk, PPI buttons pressed.) tow, low or high
(Normally takes about 1 sec-
onds.)
* Music does not start and disc
continues to rotate for STOP
—pP> PLAY or automatic selec- low
tion.
(Kd, PP buttons pressed.)
*Sound is interrupted during
PLAY. Or time counter display low
stops progressing.
° More noise during 2-axis high high
device operation.
The following is a simple adjustment method.
—Primary Adjustment—
Note: Since exact adjustment cannot be performed,
remember the positions of the controls before perfor-
ming the adjustment.
If the positions after the primary adjustment are
only a little different, returs the controls the original
position.
oscilloscope
(DC range)
BD board
TP (FE 0) ia Bl
TP (TE 0) o~=—
TP (VC)