Sony FH-B7CD - 6 Diagrams; Semiconductor Lead Layouts

RF PLL Free-run Frequency Check
Procedure :
fo counter
fella board
TP (PCK) ——
1. Turn POWER switch on.
2. Put disc (YEDS-18) in and playback.
3. Confirm that reading on frequency counter is 4.3218M Hz.
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.
* The time until music starts
low or high
becmes longer for STOP >>
PLAY or automatic selection.
(Kd, PPI buttons pressed.)
(Normally takes about 1 sec-
onds.)
« Music does not start and disc
continues to rotate for STOP
—[> PLAY or automatic selec-
tion.
(Kd, PPI buttons pressed.)
*Sound is interrupted during
PLAY. Or time counter display
stops progressing.
*More noise during 2-axis
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
i
TP (FE O)
TP (TE 0) oe’
TP (VC)
Procedure :
1. Keep the set horizontal.
If the set is not horizontal, this adjustment cannot be
performed due to the gravity against the 2-axis device.
Insert disc (YEDS-18) and press > PLAY button.
Connect oscilloscope to TP (FEO) and TP (VC) on BD
board.
4. Adjustment RV101 on digital board so that the waveform
is as shown in the figure below. (focus gain adjustment)
VOLT/DIV: 100mV
TIME/DIV: 2mS
Sek
¢ Incorrent Examples (DC level changes more than on adjust-
ed waveform)
VOLT/DIV : 100mV
low focus gain TIME/DIV : 2mS
200mV
OV
VOLT/DIV : 100mV
high focus gain TIME/DIV : 2mS
75mV
—— OV
5. Connect oscilloscope to TP (TEO) and TP (VC) on BD
board.
6. Adjusted MV102 on digital board so that the waveform is
as shown the flgure below. (tracking gain adjustment)
VOLT/DIV: 1V
TIME/DIV: 2mS
—- OV
* Incorrect Examples (fundamentia wave appears)
low tracking gain
VOLT/DIV: 1V
TIME/DIV: 2mS
—— 0V