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(2) Picture is distorted or abnormal sound occurs at intervals of several seconds.
Does JITOUT
change periodically?
(2V or more in peak
value, except
during kick)
YES
Feed system is defective (drive gain is defective: too large).
Check the waveform according to a) in (1).
Play back a simple disc with no angle change.
OK when the following waveform appears at intervals
of several seconds.
5~10Sec.
*
VDC adjustment value (including the circuit) is NG.
Check the connection to Q102 to Q108, C141 to C160, and IC101.
(3) Block noise appears in picture or abnormal sound occurs occasionally.
Does noise
exist on
RFAS3?
YES
If noise exists, check
each connector for loose
connection.
Check the line of IC101,
IC201 and IC301 (cold
solder, etc.)
Some system other
NO
than servo may be
defective.
1~1.2V
Is JITOUT
NO
higher than
2 V?
NO
Does noise
exist on JITOUT?
(Except during kick)
NO
Do pulses of
200usec or longer
occur frequently on UNCF
(TP359)? (Except
during kick)
NO
After DEM/ECC
If this voltage is too
high (2V or more, for
example), feed motor
may be defective, or
the mechanical unit
has seized.
YES
Mechanical unit
is defective.
If noise exists, check the
constant of the periphery of
YES
IC201, DSL and PLL as well
as for cold solder (connection
of "33" to "47").
YES
DEM/ECC
Note: Even with acceptable products, pulses
of 25 to 50usec may occasionally occur.
When pulses of 200usec or longer
occasionally occur, the picture may begin
to be distorted occasionally.
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