Service Manual

6. CD DRIVE MAINTENANCE AND ADJUSTMENT
6-1. Maintenance of Pickup
I) Checking the laser diode
As the laser diode wears out, the RF level
(amplitude
of eye pattern) becomes lower.
Check that the RF level is 0.8V - l.4Vp-p during
maintenance. If the RF level is less that
0.8Vp-p
then the pickup should be replaced.
2) Variable resistor on the
APC board
The variable resistor attached to the pickup on the
APC board is used to adjust the output power of the
laser. This adjustment
is done at the facto!}' and
can not be performed
in the field. If the laser's
output power
is low, the laser diode has worn out
and should be replaced. Adjusting this variable
resistor may cause damage
to the laser diode.
6-2. Laser Pickup Replacement
Procedure
-8-
Turn the power switch off and unplug the power
cord from the
AC outlet.
1
Replace the pickup.
1
Set the door close detection switch to on
manually and turn the power switch on.
Check
that the laser emits light for approx. 3 seconds
and the pickup lens moves up and down.
[Note] Be careful not to bring your eyes too
near to the laser and do not look straight
at it as this is dangerous.
l
Check the FE bias.
I
Adjust the focus gain.
1
Adjust the TE balance.
l
Adjust the tracking gain.
I
f
Check that the eye pattern waveform can be
observed at the RF test point. (0.8-1.4Vp-p)
I
i
Replacement complete
[Note] Since the adjutments influence each other,
it may be necessal}' to repeat them 2 to 3
times. times.