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XL-MXGOBK
Maintenance of Laser Pickup
1. Life of the laser diode
When the life of the laser diode has ten: a
toliowing symptoms will appear.
{1) The level of RF output ( EFM output: ampil-
tude of eye pattern) will be low.
(2)The drive current required by the laser diode
will be increased.
In. such a case, check the. life of the lier: —
diode following the flowchart below
fs RF output
more than 1.5 Vp-p?
Is the laser
diode drive current less
than 120 mA?
Replace It
2. Measurement of laser diode drive current
Replace the jump wire (W641) shown
below with
the resistor (1G).
as
Measure
the voltage
across. the
resistor with a
milli-voltmeter.
When the
voltage
is more
than
120mvV,
it shows
that the life of the laser diode
.
hae
ayvnivrnd
igs
SAPTES
<— SIDE PCB
nas e
DC MILLI-VOLTMETER
3. Semi-fixed resistor on the APC PC board
- The semi-fixed resistor on 'the APC printed' circuit
- board whith 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.
;
lf the semi-fixed
resistor
is adjusted
while the
pickup is functioning
normally, the taser pickup
may be damaged due to excessive current.
1-14{N6. 20436)
Replacement of Laser Pickup —
Turn off the power switch of RX-MXG7BK and,
disconnect the power cord fram the AC outlet',
then disconnect the system connector
Replace the pickup with a normal one. (Refer to
"Laser pickup Removal" on the previous page.)
Plug in the system connector and the AC cord
of RX-MXG7BK , then turn the power switch on.
At this time, check that the laser emits for
about 3 seconds and the objective lens moves
up and down,
|
Play a disc, and when it starts rotating, short"
circuit between TPS (TEST) and TP7 (GND).
Adjust tracking gain. ©
Adjust tracking offset:
~
Disconnect TPS {TEST} from TP7 (GND).
Check the éye-pattern at the TP8 (RF)..
:
Finishes
Note : Since one adjustment may affect other
settings, repeat, these adjustments a few
times.
:
Before installing the pickup
Unsolder the part @, which is used. for
countermeasure for static electricity.
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