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5.1
Maintenance of laser pickup (MD)
1. Confirm the life of a laser diode
When the life of the laser diode has expired, the following
symptoms will appear.
(1) Recording will become impossible.
(2) The RF output (EFM output, amplitude of eye pattern)
will become lower.
(3) The drive current required for light emitting of laser diode
will be increased.
2. Confirm the service life according to the following flow
chart.
Is the
recording power
(5.8mV) output with the
laser power under
test mode?
YES
Is the drive current
of laser diode
120mA or less?
YES
OK.
3. Method of measuring the drive current of laser diode
When the voltage measured at R337(both end) on the MD
servo control board (ENX-0223) have become 120mV or over,
the service life of the laser diode is judged to have been
exhausted.
SECTION 5
TROUBLESHOOTING
NO
Change the pickup
NO
Change the pickup
5.2
Replacement of laser pickup (MD)
Change the pickup by referring to "Removing
the pickup" in the Disassembly method.
Set the pickup to "TEST MODE" according
to the procedures described in the Adjustment
method.
Adjust the laser power.
Perform a disc adjustment.
Completion of changing the pickup.
Note:
Since this system is designed to perform magnetic recording,
the laser power ten times or over of the conventional MD play-
er will be output. Therefore, be sure to perform not only adjust-
ment and operation of this system so carefully as not to directly
look at the laser beam or touch on the body.
(No.MB351)1-41
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