(No.MB004)1-25
5.2 Maintenance of laser pickup
(1) Cleaning the pickup lens
Before you replace the pickup, please try to clean the lens
with a alcohol soaked cotton swab.
(2) Life of the laser diode
When the life of the laser diode has expired, the following
symptoms will appear.
(3) The level of RF output (EFM output, amplitude of eye pat-
tern: pin5 of IC601) will be low.
(4) Semi-fixed resistor on the APC PC board
The semi-fixed resistor on the APC printed circuit board
which is attached to the pickup is used to adjust the laser
power. Since this adjustment should be performed to
match the characteristics of the whole optical block, do not
touch the semi-fixed resistor. If the laser power is lower
than the specified value, the laser diode is almost worn out,
and the laser pickup should be replaced. If the semi-fixed
resistor is adjusted while the pickup is functioning normally,
the laser pickup may be damaged due to excessive cur-
rent.
5.3 Replacement of laser pickup
Is RF output
0.9 0.22Vp-p?
YES
NO
O.K
Replace it.
Turn of the power switch and, disconnect the
power cord.
Replace the pickup with a normal one. (Refer
to "Pickup Removal" on the previous page)
Plug the power cord in, and turn the power on.
At this time, check that the laser emits for
about 3 seconds and the objective lens moves
up and down.
Note: Do not observe the laser beam directly.
Play a disc.
Check the eye-pattern at 5pin of IC601.
Finish.
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