Electrical Block Checking - Sony CDP-997 Service Manual

—
| CDP-997
SECTION 4
ELECTRICAL BLOCK CHECKING
Check in order of descriptions below.
2. The disc [YEDS-18] part code No. 3-702-101-01, should be
used but do not apply it unless direction is given.
3. Use the oscilloscope with more than 10 MQ impedance.
[RF Level Check] Oscilloscope
(DC range)
BD board
aa C)
TP (RF) on—0 +
TP (VC) Ow—0-
1. Connect the oscilloscope to test points, TP (RF) and TP
(VC).
2. Tur POWER switch on.
3. Insert the disc (YEDS-18) and to press [> PLAY button.
4. Check the waveforms to be normal and RF level to be
proper. Normal waveforms means © form can be observed
clearly in the center of the each waveform.
VOLT/DIV : 200 mV
RF signal waveforms TIME/DIV : 500 nS
X\)
:
)
iy mi)
ANY
M WM M ()
40.25
A=1.2 02 Vp-p
AA
4
[E-F Balance Check]
CS, Gobo
Oscilloscope
(DC range)
BD board
eenee OP
TP (TE!) om——o}
TP (vc) o-~w—lo-
Earch TP (ADJ) and TP (TE).
Connect the oscilloscope to TP (TEI).
Turn POWER switch on.
Insert ther disc (YEDS-18) and press the [> PLAY button.
Confirm waveforms of the oscilloscope to be vertically
symmetrical in relation to OV line.
Remove the earths of TP (ADJ) and TP (TE).
(Note) Prolonged sweeping time makes it easy to see.
\
A A
ov B B
A=B A=B
[RF PLL Free-running Frequency Check]
Main board Frequency counter
SOR ea
TP (XPLCK) O"#—9+
1. Tum POWER switch on.
2. Insert the disc (YEDS-18) and push the [> PLAY button.
Confirm the frequency of TP (XPLCK) to be 4.3218 MHz.
[Focus/Tracking Galn Check]
Focus/Tracking gain determines the follow-up of pick-up relating
to mechanical noise and shock which occur when the 2-axis
device operates.
However, as these are contrary to each other, the micro-computer
automatically adjusts the position to the point that both are
satisfied with.
e When gain is raised, the noise in the 2-axis device operation
increases.
¢ When gain is lowered, it is more susceptible to mechanical
shock, and tends to skip easily.
When gain is not normal, the symptoms below appears.
¢ In spite of STOP =®[> PLAY or
low
without music begining to play.
¢ It takes longer time till music starts
when STOP =*f> PLAY or automatic ine inwerhiai
selection (4, >» buttons pressed). 8
(Normally it takes about 2 seconds).
automatic selection (4, >» button
pressed), disc continues to rotate
¢ Sound is interrupted during PLAY.
Or the time counter display stops to low
progress. ;
¢ The noise increases during 2-axis p
devi ; high
evice operating.