Cd Player Adjustment Procedures - C.E.C. CH3000 Service Manual

CD PLAYER ADJUSTMENT PROCEDURES
BEFORE CHECKING OR ADJUSTING CD PLAYER
1. Procedures for all adjustments for the CD player from
start to finish are described below.
TRACKING GAIN ADJUSTMENT
The measurement circuit diagrammed below must be used in
order to adjust tracking gain correctly.
1. Set the variable resistors to the initial positions listed
below:
TRORY = 10K 0039
P106 (FREE RUN FREQUENCY) .... Mechanical Center
PLL (VCO) FREE RUN FREQUENCY ADJUSTMENT
1. Connect the frequency counter between the VCO test
terminal CK and to GND. (Use a 10:1 Probe)
Measurement Circuit
Apply P103 to the position of Mechanical center position,
and place the test disc (Modern Wave HI) on the Disc
Tray.
OFF.
NOTE:
If these two adjustments are performed, the TRACKING
OFFSET must also be adjusted.
3. Place the test disc (Modern Wave II) on the Disc Tray,
and play the fourth item on the disc.
4. Connect a OC Voltmeter and an oscilloscope via the low
pass filter tike that shown in the illustration below to the
test terminal TE (tracking error).
22k
TE ouTt
GNO
Measurement Circuit
Fig 1.
5. Adjust P101 so that the DC Voltmeter reading is
0V+450mvV (oscilloscope waveform is symmetric to + and
— about the zero level).
CONFIRMING HF LEVEL & 3T JITTER VALUE
if no jitter counter is available, this check does not have to be
performed.
PLAY the fourth item on the test disc (Modern Wave II).
CONFIRMING TE LEVEL
1. PLAY the fourth item on the test disc (Modern Wave II).
2. Connect an oscilloscope to the test terminal TE, and
check that its TE level is in the range at more than 2V 1.
(P-P). 2.
If the results of the above procedure are not satisfactory,
the Pick-up is damaged.
Connect an oscilloscope to the test terminal EFM! and
check that its HF tevel is in the range 2.0Vp-p ~ 3.3Vp-p.
(Use a 10 :1 Probe)
3. Connect a jitter counter to test terminal EFM! and check
that the 3T jitter value is less than 25ns.
(Window width:600ns ~ 850ns, Set Level:2.5V)
4. Now PLAY the tenth item on the test disc and check that
the jitter value is less than 25ns again.